In 2003 Ford began phasing out one of the greatest truck engines of all time. The 7.3-liter Power Stroke served as a reliable workhorse for years, but now it was time for truck buyers to get more power and cleaner emissions. The 6.0-liter Power Stroke launched that year and punched out more power, but also started to punch out wallets with expensive problems. What could have been a beloved follow-up is still hated by many today, and used truck prices reflect it. But was the 6.0-liter Power Stroke really that bad? Let’s take a look.
Diesel truck fans have a list of engines often considered to be the greatest of all time. We aren’t talking about just one brand, either. Fans of Ford, Chevrolet, and Dodge all have their faves, and that’s not even getting into the mills from outside of America.
Proponents of Dodge still love the 5.9-liter Cummins 12-valve straight-six turbodiesel and the fact that these engines will probably continue to work after the heat death of the universe. The folks in love with the General dig the 6.6-liter Duramax LBZ turbodiesel V8 for its ability to produce truckloads of power without the complications brought on by modern emissions systems. People are still paying near-new prices for these trucks even though it’s been nearly two decades since they were in production.
If you’re loyal to the Blue Oval, the Navistar/Ford 7.3-liter Power Stroke is a legendary engine. It’s been over two decades since the last 7.3 was built, yet enthusiasts continue to pay tens of thousands to own an example of one of greatest diesel engines of all time. Sure, a stock 7.3-liter doesn’t make a ton of power compared to today’s trucks, but these are engines that can last longer than the metal bodies in which they’re packaged.
Such status has escaped its successor, the 6.0-liter Power Stroke.
In theory, the 6.0 had the right ingredients to rise to stardom. The new engine had to comply with stricter emissions, but it still made more power out of the factory than its predecessor. Unfortunately, the 6.0 Power Stroke would encounter a long list of issues and give tuners even larger headaches. The 6.0 carries such a reputation today that it’s sometimes called the “6.Blow” and you can sometimes find newer trucks with the 6.0 selling for cheaper than an older truck with a 7.3.
But how did things get this way?
A Great Start
To get an understanding of why enthusiasts were so disappointed in the 6.0, let’s look at what came before.
The Ford 7.3-liter Power Stroke started life with a different company and with a different name. Our readers with experience in heavier trucking are familiar with the Power Stroke as the Navistar T444E. These engines served as the backbones of fleets for decades. If you were a driver in the 1990s or, heck, even today, there’s a chance your streets were plowed by a truck with one of these engines. If you were a kid like I was, you started each day with the familiar clackety sound of a DT466E or a T444E in the yellow school bus that picked you up. T444Es found homes in everything from box trucks to garbage vehicles.
Navistar used to be known as International Harvester, and the company’s history is filled to the brim with machines built for work. International Harvester’s roots were in the 1800s with reapers, but the company helped change farming in only 1905 with its first tractor. The famous Farmall tractor would come later in 1924. International Harvester’s colorful history includes feats such as the Cub Cadet lawn tractor, as well as light duty on-road vehicles like the Travelall, the Travelette, and the Scout.
International Harvester’s impact on diesel started in 1932 with the impressive McCormick-Deering TD-40 TracTracTor crawler tractor. The 461 cubic inch four-cylinder engine in this beast got around the problem of cold diesel hard-starting by first slurping up gasoline before switching to diesel.
International Harvester was even one of the first American companies to put a diesel engine in a light-duty pickup truck. 1963 through 1968 model year C-1100 to C-1300 IH trucks could be had with diesel power, making them what some call America’s first factory-built diesel-powered light-duty trucks.
In the early 1980s, right around when the International Harvester name departed from light-duty on-road vehicles, Ford embarked on a journey for a new kind of diesel truck. The diesels of the era were not like the powerful trucks of today, but engines that got better fuel economy than their gasoline counterparts. In at least one case, going diesel even meant giving up on power. Ford felt there had to be a better way. The Blue Oval believed it was possible for diesel engines to evolve from thrifty powerplants to ones that delivered a kind of capability, durability, and power never seen before.
At the same time, International Harvester was looking to build a diesel engine for an automaker with a lineup of pickup trucks. General Motors was already married to Detroit Diesel, but Ford turned out to be a great marriage partner. Ford wanted power and International Harvester wanted to deliver.
First came the indirect injection diesel engine, but trucks in the 1994.5 model year and beyond got something special: the mighty 7.3, which brought direct injection, computer control, and more. From my retrospective:
One key component to the 7.3-liter Power Stroke and the Navistar T444E is the HEUI system, which stands for Hydraulically Activated, Electronically Controlled Unit Injector. It’s a complicated computerized system that uses pressurized oil to fire the engine’s injectors. HEUI technology made its debut in 1993 by Caterpillar and Navistar teamed up with the former to provide the technology to the T444E, Power Stroke, and another famous engine, the Navistar DT466E straight-six turbodiesel.
A lot is going on in the HEUI system, so I’ll try to simplify it. A low-pressure lift pump sends 40 to 70 psi of fuel to the injectors in early Power Strokes. Later 7.3s send 60 to 65 psi of fuel. The powertrain control module commands an injection event and the injector driver module triggers the injector solenoids. When this happens, the solenoid pulls an internal poppet valve off of its seat, allowing high-pressure oil into the injector. That oil comes courtesy of a high-pressure oil circuit charged by the high-pressure oil pump. The HPOP sends high-pressure oil into the injectors, which forces a piston in the injector down, lifting a nozzle. This pressurizes the fuel in the injector. The nozzle then opens and 3,000 psi of fuel pressure multiplies to 21,000 psi of fuel pressure in the cylinder.
All of this happens with computer and electronic control, allowing for the control of injection events independent of what the crankshaft is doing. HEUI is able to provide peak pressures under a variety of conditions, helping to keep power up, fuel consumption down, and emissions down as well. Some quirks come with HEUI, such as the fact that you technically cannot run it out of oil. The system requires a minimum amount of oil. A 7.3-liter Power Stroke holds some 15 quarts of oil. Once you run it below 7 quarts or so, the HEUI system just won’t have enough oil to permit an engine start.
HEUI joins forces with six head bolts per cylinder, a Garrett turbocharger, forged connecting rods, and a fluid-to-fluid oil cooler to provide high performance and a lifespan that could outlive you. Later examples of the 7.3 got a wastegate for the turbo and an air-to-air intercooler. There was also a brief moment between 2001 and 2003 when powdered metal con-rods were used.
As I said earlier, the 7.3-liter Power Stroke is known for relative bulletproof reliability in stock form. Tuners have also found the engine to be receptive to taking on more power, too.
A New Engine
Unfortunately, the 7.3 was built for a different era.
By the early 2000s, diesel engines were ramping up in power, leaving the old reliable Navistar engine in the dust. GM truck buyers got to enjoy 300 HP and 520 lb-ft of torque from a 6.6-liter Duramax LB7 V8. Meanwhile, Ram buyers got a 5.9-liter Cummins straight-six with 305 HP and 555 lb-ft of torque. Ford buyers? Well, the best they got from a stock 7.3 was 275 HP and 525 lb-ft of torque, assuming a manual transmission. Power fell to 250 HP with an automatic.
Times were also changing. As Motor Trend notes, regulations for 2003 would have required Ford to equip the aging mill with exhaust gas recirculation, which would have put the 7.3 even further behind the competition. Navistar and Ford decided that the best way forward was to build an all-new engine with the power to compete and the emissions to keep the feds happy.
The International Truck and Engine Corp. decided to take a high-tech approach with this new engine. As Fleet Owner reported in 2002, several improvements were implemented:
The key to the VT 365’s increased performance, despite tighter emission controls, rests on several components. First is the Electronic Variable Response Turbocharger (EVRT), which provides improved throttle response and peak torque capability at lower rpm levels. Second, it is equipped with Electro-Hydraulic Generation Two (G2) fuel injection technology, which is based on a low-pressure common rail fuel system. Finally, Intuitive Shift controllers allow for smoother driving to compensate for the use of cooled Exhaust Gas Recirculation (EGR) technology, which cuts oxides of nitrogen (NOx) emissions.
“The VT 365 has four valves per engine cylinder, compared to two valves per cylinder in the T-444E. That gives the VT 365 better air-flow capability, which translates into better acceleration for drivers especially in stop-and-go environments,” says Mark Wildman, International’s field service manager.
The G2 fuel system uses high-pressure injectors developed jointly by International, Sturman Industries and Siemens Diesel Systems Technology to more efficiently manage fuel consumption. Higher injection pressure combined with four valves per cylinder increases performance and fuel economy while lowering emissions.
But that wasn’t all, as the 6.0 iron block V8 was physically a different engine. The 6.0 featured an oil cooler and high-pressure oil pump integrated into the block, helping the engine earn a more compact size than the outgoing 7.3-liter engine. Navistar’s continued changes by relocating the gear train to the rear of the engine and reinforcing for the bottom end. The crankshaft main and rod bearing surfaces were treated to an induction-hardening process and the crankshaft itself was held in place with a plate.
Powdered-metal connecting rods also made a return in the 6.0. These rods were panned during their short life in the 7.3, but they found a good home in the 6.0 engine. As DrivingLine explains, the 7.3’s engine revved low and submitted a lot of torque to the rods. The 6.0 revs more and the rods live an easier life. Reportedly, the rods in the 6.0 are known for durability.
International called this engine the VT365, and it was sold with horsepower ratings as low as 175 HP to as high as 230 HP. Torque peaked at 620 lb.-ft. Ford’s application of this engine (which could be found in lots of other machines) was called the 6.0 Power Stroke, and it went even further, hitting 325 HP and 560 lb-ft of torque in 2004 model year Super Duty trucks.
On paper, this engine was great. It put Ford back into the diesel truck power wars, and its EGR system satisfied emissions regulations. The variable geometry turbo was also great, allowing for hard power early on and throughout the powerband. Unfortunately, problems started getting reported in 2003 while these engines were still new.
What Went Wrong
There are a number of issues that plagued the 6.0 engine during parts of its life. Thankfully, time heals a lot of wounds, and there are now solutions to the engine’s infamous issues.
Perhaps the biggest problem with the 6.0 and the VT 365 comes from the engine’s torque-to-yield head bolts. The bolts are a sizable 14mm, but there are only four bolts per cylinder, compared to the six bolts per cylinder found in the 7.3. Unfortunately, the cylinder pressure under the head is a lot, and has been found to stretch the stock bolts, leading to an eventual blown head gasket. Reportedly, this happens most often with modified engines, but has happened with stock engines as well.
As I said before, there is a fix for this, and it’s tossing the factory head bolts in the trash and replacing them with stronger studs (above), hopefully putting blown gaskets in your rearview mirror.
While blown gaskets are an infamous problem with the 6.0, it’s not the only source of headaches. The oil cooler is another problem child. It’s located at the front of the lifter valley and integrated into the block itself. This cooler is a critical component because it cools the oil that runs the high-pressure oil pump, the oil that runs the injectors, the oil that cools the turbocharger, the oil lubricating the engine, and the oil cooling the EGR cooler. That’s a lot of important parts that depend on the oil cooler.
Sadly, the 6.0’s oil cooler is known for plugging up, which has a cascading effect of allowing the oil in all impacted components to reach dangerous levels. The resulting temps can kill expensive components and cause a catastrophic failure. DrivingLine notes that around 90 percent of 6.0 EGR cooler failures start with a plugged oil cooler. The remedy to this problem is installing a coolant circuit filtration system, which should catch nasty particles before they plug the oil cooler.
Still, if you’re unlucky, you may find yourself replacing the high-pressure oil pump. Or more. This is a big deal because you need high-pressure oil to activate the fuel injectors (per Ford: “The 6.0L Power Stroke Diesel Engine utilizes a hydraulic injection system where high pressure engine oil is used to compress diesel fuel. The fuel injector is used to precisely control the delivery of the fuel into the combustion chamber”). Unfortunately, the HPOP is located at the back of the engine under a cover and the turbo. The cab covers much of the engine, but an HPOP replacement can happen without removing the cab. It’s just a task that can take a backyard wrencher several hours.
Since we’re talking about oil, let’s look at the injectors. Oil pressurized as high as 3,600 PSI enters the injector through an electronically-actuated spool valve. The oil-actuated injector fires fuel into the cylinder at 26,000 PSI, 5,000 PSI better than the outgoing 7.3 engine. There are a lot of parts that can fail related to the injectors. You need low-pressure diesel fuel, a 48-volt, 20-amp coil to operate the spool valve, and high-pressure oil that hopefully isn’t blazing hot. Screw one or more of these up, and the injector can fail.
Somehow, we’re still not done with issues yet. Next, we have the fuel injection control module (FICM), the computer responsible for opening and closing the spool valves and thus, getting fuel to the cylinders. This module is the one sending 48-volt pulses to the coils and while its lower than the 100 to 120 volts utilized by the 7.3, any low-voltage problems with the truck could cause running issues. Additionally, the FICM itself is known for eventually failing.
All of this sounds scary, but for some people it’s worth it. In 2020, I owned a Ford E-350 van with a 6.0-liter Power Stroke.
It had 287,000 miles on its odometer and came with a stack of service paperwork. Big ticket items included four injectors replaced before I bought the van and a turbo perhaps 50,000 miles before that. Oh yeah, that’s another problem I didn’t note. The Garrett GT3782VA turbo in these engines sometimes got gunked up with corrosion and carbon, leading to sticking. Some mechanics remove the cab from above the 6.0 engine to make replacing the turbo and heads easier. Lack of easy access is another downside to these trucks.
Yet, my van, which was stock, still drove on its original head gaskets and even still had its emissions equipment intact. It got 18 mpg with me behind the wheel — good compared to my friend with a stock 7.3 Power Stroke that got 13 mpg on a good day. Sadly, the van was detuned compared to Super Duty trucks and made 235 HP and 440 lb-ft of torque. But it still made that glorious diesel soundtrack so I didn’t care one bit.
I then drove the van thousands of miles without issue before a team of drug enthusiasts took it upon themselves to turn my van into a “science lab.”
Does The 6.0 Engine Still Suck?
I mentioned some “bulletproofing” tactics above, but there are others. Some owners replace the variable geometry turbo with a fixed geometry turbo, conduct more frequent flushing of the oil cooling system, and clean the EGR system.
Some believe that a 6.0 can be a reasonably reliable engine if it’s left stock and you’re anal with your maintenance. This is a departure from the 7.3, which can seemingly take all kinds of abuse all day every day. But, if you’re the kind of person who drives a stock truck, you may not get burned by a 6.0. It sounds like bulletproofing is a must if you want to send power to the heavens. Either way, it doesn’t hurt to spend some extra cash to zap known issues.
So, is the 6.0 a bad engine? It seemed like it was when it was new. Today? I suppose that depends on who you ask. Some still despise the engine. I was one of the people who wasn’t burned by this engine, but then again I didn’t own it for long and it was detuned in a van. Other people may not be so happy with their experience. It may not be the engine for you if you want to beat the daylights out of the truck or want to put down 700 HP at the wheels without some extensive work. Some searching of the web shows you can get newer 6.0-equipped trucks for a similar price to older 7.3s with more miles.
There is good evidence in favor of the 6.0 being a bad engine. In addition to the failures, and I didn’t even list all of them, Ford was sued over the engine’s problems. As USA Today reported, Ford knew something was wrong:
Ford initially denied a problem existed, then claimed there was insufficient evidence to prove the claim and finally maintained the company wasn’t aware of the extent of the diesel engine problem. Internal emails written by upper level management shattered the Ford defense.
One email presented during trial was dated five months before Margeson purchased his truck. John Koszewnik, Ford’s North American diesel division director, wrote on Feb. 5, 2006, that warranty repairs on the 6.0L engine were running “as high as $5 million a month” and added Ford would not invest in an engine upgrade. Two hours later, according to court records, Koszewnik warned people not to forward his email.
Mike Frommann, the Ford warranty manager, emailed his colleagues warning that the diesel engine could lead to a class action lawsuit if its cylinder pressure specifications went public. He wrote in an email to colleagues dated July 13, 2006, “I recommend we delete all these emails.”
But it got even worse, from USA Today:
By February 2007, warranty repair costs on the engine exceeded $400 million, including more than $227 million to fix fuel injectors and more than $182 million on turbochargers, which was the largest repair rate ever seen for any Ford engine. This information was taken from an affidavit by one of Ford’s own officials in a lawsuit it filed against Navistar. Despite this testimony, Ford later denied engine problems when it was being sued over the Navistar engine.
The appeals court affirmed there was “adequate evidence of intentional concealment of these problems by Ford to the detriment of consumers.”
The article goes on to note that Ford was not only sued in a class action, but six individual owners sued as well. Charles Brian Margeson was awarded $214,537.34 plus legal fees while five others collectively won $10 million against Ford.
In terms of sales, I could not find data that breaks the Power Stroke off on its own, but Ford continued to sell nearly a million F-Series trucks a year through the Power Stroke’s run of 2003 to 2007 in trucks and through 2010 in vans. While the engines were problematic, it seemed people just kept buying them, anyway.
I suspect that the 6.0 Power Stroke will continue to be passed on by enthusiasts as the years go by. The 7.3 Power Stroke can still be found in plentiful numbers while Ford’s newer Power Strokes are known for better reliability. I mean, I got to haul 40,000 pounds with a 6.7 Power Stroke last year, something a stock 6.0 could only dream about. If you’ve owned a 6.0-liter Power Stroke, I want to hear more. Did it treat you well? Or did you want to sue Ford over its issues?
Images: Manufacturers, unless otherwise noted.
Top graphic fireball: Jag_cz/stock.adobe.com
Bought an 06 Cummins new. Still runs great. Replaced the cooling fan assembly under warranty. No major out of pocket repairs. Few friends have owned the Ford 6.0l PS. Everyone of them needed expensive repairs.
It was designed, if I have it right, just before Fiat blew the world apart with common rail diesels, which were an immediate improvement in fuel consumption, power and emissions — common rail diesel exhausts do not even smell of diesel.
And they uses piezo injectors, so they could work as fast as electricity — you still get motors with seven separate injections per stroke, which I think is amazing.
Fiat started with common rail in small cars but now they are everywhere — even in marine engines.
Not all common rail diesels use piezo style fuel injectors. Some use solenoid (coil) type injectors which are capable of multiple pulses per combustion cycle, even though the solenoid type do not react as quickly as piezo type do.
I’ve got an ’06 F-350 with the 6 liter and absolutely love it. Crew cab, lariat, 8′ bed with a canopy. I bought it in 2008 with about 40k miles. My 16 year anniversary with the big bitch is next week actually. It has a bit over 150k miles now. I’ve had to do some work on it (the usual suspects and expected/planned for) but it’s never left me stranded. I put a coolant filter on it fairly soon after buying it. My cat and EGR system fell off in boating accident a few years later. It got a tuner at that time too. Several years later my head gaskets said uncle. It’s studded now, got a new oil cooler at that time. It is a secondary rig. Mostly camping/hunting/boat duty. Pulled ~12k lbs a handful of times. Mostly 4-6k though. Seen as high as 18mpg on flat highway. Averages ~14 cruising around town and about 13mpg pulling a 6k pound boat over the coast range (1800′ pass). Great power, decent economy (for what it is), and still my favorite generation of ford truck appearance wise. For all the love the 7.3 gets it is louder/harsher than the 6.0, that generation of truck was way more crude to drive, and the 4 speed auto you are primarily stuck with blows for towing. My dad has had a couple 7.3’s with both the 6 speed and 4R100. I’ve driven them extensively and I’d take my truck 10 times out of 10 over either.
Every time I read about an engine with fundamental design flaws, it’s always 4 bolt heads and/or an open deck (Olds 350 diesel, Vega, etc). You’d think they would have learned from this long ago.
My truck has a Detroit 6.5 diesel, which is another engine you could write a whole article about. But it’s been pretty reliable for me.
“We can save money with less bolts. It’ll work this time..”
They really are junk. I am one of those that said “With good maintenance, working it hard, it can’t be possibly that bad”. Well, it is.
Purchased a 2005 F-350 King Ranch with 150k miles and a GLORIOUS two tone paint job. I loved that truck, the aniline seats, the look. It came with a stack of papers, including a recent turbo, injector, EGR, oil cooler, etc. replacement. Not tuned or bulletproofed, which I wanted.
Ran it hard for the next 2-3 years towing heavy….5k synthetic oil changes, 10k fuel filter changes….and blew…everything listed in this article. 4-6 Injectors, Turbo vanes stuck, blown CAC tubes, clogged the oil cooler with 187k, blew the EGR and lifted the heads towing into Asheville. It spent almost as much time as Ford dealers for various ailments as it did towing. I limped it into a Ford dealer guzzling coolant and smoking, and traded it for basically nothing for a 2017 6.7L.
I paid $12k in maintenance for 30k miles, and the previous owner at put $12k into it before I bought it. $.48/mile in maintenance. Insanity.
The 6.0 was perfectly fine in the lower power medium duty truck specs it was originally designed for. The problems came when Ford cranked the power up too much for the pickup trucks because big numbers is what sells big trucks. I’m still in the camp that if you bulletproof a 6.0, put a reasonable tune on it (not some big power lope and smoke garbage), and actually keep up on maintenance, it’s a very solid engine
It’s the 6.4 that people can’t give away. That motor (while I do know some that have been reliable) really can’t be fixed. At this point – especially given the age of these trucks – if you know these motors then the 6.0 can be a decent choice. There is a fix for all of its issues so it is plenty reliable on a good chassis, but because of its reputation values have stayed lower so upfront cost is lower.
The budget buyer doesn’t want it because it costs real money to either pre-emptively or post fix. The fanboy doesn’t want it because it isn’t a 7.3 or ‘Cummings’ (yes, that’s how they usually spell it). And like you said, the 6.7 is now old enough to make more sense for many. But the 6.0 is a fine buy if you know.
I think the 6.4 escapes a lot of the memes and big criticism because they only made it for 3 years so there’s far fewer of them out there. I’ve always said, you can fix a 6.0 and have a pretty solid engine as long as you’re reasonable and actually do your maintenance but there’s nothing you can do to fix a 6.4
Your “Cummings” reference reminds me of all the “audio enthusiasts” and also car owners spelling and typing their BMW has a “Harmon Kardon” sound system
my dad had a 99 powerstroke f350 4×4 and my moms got it now and i made her promise she would never sell it because itll survive the apocalypse. unfortunately she listened and she wont sell it to me either. shes getting near 70 and has some health problems and driving it scares her so it just sits in her driveway rotting. she has to replace both batteries every year and the tires dry rot. ive taken it out a few times when shes traveling and i can get it started. it still gets 16-17mpg even with big stupid k02s she let the tire store talk her into because they look cooler.
that gen super duty had a little green overhead driver information center and somehow ford screwed up the design so bad it gets so hot the solder on the resistors on the mainboard heats up and the resistors drop off the board. you have to take it apart and reattach them to get the DIC working again.
that’s interesting. I remember those were everywhere in Ford’s F-Series, Expeditions, Excursions and Explorers of the era.
what kinda shitty solder was being used??? I do electronic board assembly and we have to heat our irons to ~720 degrees farenheit to melt solder???
Could be mechanical stress from thermal cycling plus vibration rather than heat actually melting the solder.
I bought a F-250 with the 6.0 from a plumbing company a few years ago with ridiculously low miles for super cheap. I actually really liked the truck, and since it hadn’t been modified, it didn’t need a lot of work. New thermostat, new glow plugs, a preventative oil cooler swap to the newer, better version, and a couple of injectors that had crudded up due to sitting, and it was pretty golden. I think I spent about $1500 getting it back to 100% reliable, on top of the $1900 I bought the truck for didn’t seem like a bad investment. I ended up selling it for $8k during the pandemic, when I switched to a supercharged 5.4 F-150 for my truck needs.
The 6.0 was a perfectly driveable engine, plenty of power in stock trim, and hauled dirt, rocks, gravel and trailers like they weren’t even there, and got decent mileage doing it. It was a little cramped to work on, but really not that bad.
I purchased a 6.0 a few years ago that had 170k on it. The guy had all the paperwork for the “bullet-proofing” so I figured I was good to go. within three months I had to replace both from hub assemblies, which I guess is reasonable since it had 170k on it. Right after that it started leaking oil and the trouble never stopped coming. It was heavily tuned and even had a built transmission so I thought it could’ve had some issues with it making 600 or so HP but good grief it emptied my wallet. I sold it for a good loss a couple years ago after owning it for about 1.5 years. I easily spent 4-5k on it in that short tenure on maintenance and such. I even had a friend offer me a 7.3 with lower miles towards the end that I declined because I value my friendship with him, haha.
Haha yup never take/buy a vehicle from a friend or sell/give one to a friend if you value your friendship. Though I did sell a 78? Nova to my buddy because I pulled the engine from it to put in my Firebird but he was the one that helped me haul it to my dad’s garage and offered to buy it once we got the engines swapped so it was a planned ordeal so no broken friendship haha.
“ It was heavily tuned”
That was likely the root cause of a lot of issues. I wonder how it would have been if you gave it one of the heavy duty truck tunes that made way less power, but are designed for durability.
Honestly, 170K miles with a very aggressive tune like that is a recipe for high maintenance with just about any engine.
I have a good friend who inherited an F250 with the 6.0L. The family member had purchased it new and was excessive about maintenance and care of the truck. The truck was bone stock and made it to about 200,000 miles before the head bolts gave up. At that point it had been through a couple of rounds of injector replacements and three turbos, at least some of which was during the warranty period, and at least one warranty replacement of the oil cooler. There was a full book of all the service records of when my friend inherited the truck, and we did some quick math of how much it cost to get it to 200,000 miles and it was over $10k in just 6.0L-specific engine repairs. When the head bolts gave up, the family member had head studs, refreshed turbos, an oil cooler filter with external cooler, and yet another round of new injectors installed for another $8k (it was like $6200 in parts and $2k in labor). My friend has owned it a couple of years and is close to 300,000 miles on it, though getting it to that point has been another $5k in parts and labor for another set of new injectors and EGR replacement.
As a counterpoint, my old tuned LLY Duramax made it to 100,000 miles with routine oil changes and nothing more, and was still going strong with nothing beyond routine maintenance when I sold it. That’s not to say the Duramax didn’t have its own issues, but they were far less widespread than the 6.0L.
This is why I have preferred my 12v over so many other diesels everything is mechanical on it. I have yet to worry about injectors or fuel pumps failing it has 250k miles on it and all stock parts on the engine side. Sure somethings like injector gaskets and valve cover gaskets have been replaced but really nothing else. Still on the stock turbo surprisingly. Cannot say the same for the other parts though had to replace the rear end last year as the stock dana 70 just decided it didn’t want its passenger side axle attached anymore haha
I have a farmer friend who feels the same way about his Ford IDI motors. He has a couple trucks with close to 500,000 miles of hard farm use with the IDI motors in them and while they aren’t exactly powerful, they are robust. Much like you, the rest of the trucks are showing those hard miles pretty badly.
Those are also motors I have never heard anyone complain about besides the low power (which is to be expected out of a non turbo diesel from the 80s) but they are stupid simple engines unlike the stuff today with all kinds of different electronics, sensors and emissions controls. Though I have heard good things about the 6.7’s today I have also heard horror stories with the DEF systems.
So, I worked for International for 3 years as a tech. These engines really do get a bad rap and I wouldn’t hesitate to buy one. They have issues, but they’re all known quantities and if you do the labour yourself, not overly expensive in the diesel realm.
Now, the Maxxforce 7, aka the 6.4 Powerstroke, is a hot pile of garbage. Most trucks we had come in, the engine was toast by around 100,000 miles. We’re talking school buses and box trucks. This is pitiful. Let me make a short list of crap we had to fix:
-Compound turbos coking up with EGR gases and failing
-wastegate actuator failures, causing overboost and limp mode
-High pressure fuel pump failures (in the valley, under the turbos)
-Rocker arm failures (pushrods wear through the rockers, brass-tipped pushrods and all new rockers was the fix, didn’t stay long enough to see if this cured things)
-Fuel dilution was huge. It wasn’t uncommon to drain 24L out of a pan that was supposed to have 19L in it.
-Fuel rail pressure sensor internal failure, causing diesel to wick up through the harness, toasting the entire under valve cover harness, and often the next section as well.
-Constant aftertreatment issues
-Straight-up piston failure. We changed more short blocks on the Maxxforce7 than ANY OTHER engine in our lineup.
These things lived fast and died young. They had boatloads of power, until they exploded. Which was often.
The fuel dilution was likely cause by the insanely large piston to wall clearance when cold. If you had a fresh short block in front of you, you could grab the piston and clack it back & forth in the bore.
My co-worker called them “flopappotamus” pistons.
TL;DR,
6.0 flawed, but “I can fix her”.
6.4 will make you swear off diesels forever.
Yeah I have never heard good things about the 6.4’s reason why they were only around for 3 model years. Besides hearing you could build them to a lot of power yeah nothing good. Also being the first Ford truck to require DPF does not help. Funny thing is International is still having issues with DEF to this day.
The entire Maxxforce line was built on the premise of “we can meet emissions without DEF”.
So what did they do? They used massive amounts of EGR. Upwards of 80% duty cycle in some applications.
Every engine in that lineup ate EGR coolers for breakfast.
Hah worked out so well for them and I would assume any 6.4 you still see on the road most likely has had the DPF deleted at this point. If not that maybe owned by a grandpa that only drives it 1k miles a year.
I worked with a guy who bought a brand new F350 with the 6.4L and it was a nightmare from the get-go. He eventually got Ford to buy it back after what I swear was nearly a year of dealer-provided rental cars (apparently he needed a new short block and they were hard to get back then).
They were hard to get BECAUSE THEY KEPT EXPLODING. I saw one once with over 200,000km on it and I was genuinely shocked. They ALL failed somewhere between 120-160k kilometers.
The really heavy fuel dilution in 6.4s is likely from a leak somewhere in the HP fuel system. The 6.4 was at it’s core a 6.0 that was kind of quick and dirty adapted to common rail. But since basically the whole HP system is under the valve covers or in the valley, almost any fuel leak drains down into the crankcase. I’ve seen 6.4s overfill their crankcase bad enough to where it gets sucked back into the intake through the crankcase vent and then they melt down pistons because of the cool new unmetered fuel source it has.
There’s basically no similarities between the engines from what I can remember working on them (admittedly, 10 years ago now). If they even shared a single part number I’d be shocked.
There wasn’t anything directly cross compatible like that but the core block and head designs were modified from the 6.0. They aren’t directly identical but they were modified as little as possible to convert to common rail, the injector return passage in the head on 6.4s was the same passage that was used for the fuel supply to the injectors in the 6.0. It’s been a while since I’ve been around diesels too but I believe the 6.4 head will physically bolt onto a 6.0 block, but obviously it wouldn’t actually work.
I wasn’t around first hand but this is what I was told from Ford employees and technician trainers who were doing diesel related work at the time the 6.4 was coming out. Also apparently it was no secret that the 6.4 was just a stop gap engine until the 6.7 was ready. A friend of mine was a diesel tech at a Ford dealer at the time and he remembers one of the technician trainers straight up telling them that during a training class.
I’ve only heard this nth-hand, but apparently the 6.0 is somewhat redeemable with some of those modifications but the 6.4 that came after it was so bad that it ended the Navistar-Ford collab forever, and almost no amount of bulletproofing can save it.
Very interesting!
Thrilled to read this, and it fits with the hearsay I’ve gathered, boiling down to “it can be an acceptable engine when it’s bulletproofed, but that’s also a very expensive prospect if you’re paying someone else to do it.”
The thing I’m curious about was that it was only recently someone told me the 6.4l PowerStroke that followed it is even worse, reliability-wise. Haven’t heard much about it (or really much about the 6.7l, to be fair) so I’m certainly curious.
….but of course, I live in Pennsylvania, so any personal anecdotes should be taken with a grain of salt. Freakin’ “emissions deletes” are quite common. I imagine those significantly impact engines’ reliability, so…yeah.
Looking forward to the day trucks with emissions equipment intentionally removed receive more attention/punishment.
Impacts in a good way. Modern on-highway diesel emissions is a dog for maintenance and downtime, which is why pre-emissions trucks are selling for almost original MSRP if not more. The modern SCR-DPF systems directly cause about 4-6% more fuel consumption. One wonders if the amount of extra CO2 that produces across an entire first world economy’s worth of transportation is even justifiable by the reduced NOx.
My peeeeeeeeeeersonal opinion is that a lot of the enviromental science behind “This substance causes 2.2 million excess deaths per year!” that emissions regulations are pitched under across the political spectrum are skewed and the claims are embellished. But that’s just like, my opinion, man.
I mean, the EPA says “the impact of 1 pound of N2O on warming the atmosphere is 265 times that of 1 pound of carbon dioxide”, and the ICCT presents a summarized case here that’s it not (or at least not as much of) an either-or situation as you present.
I went down the 7.3 rabbit hole. I recall reading somewhere that Navi was shut out/ignored during the development.
I had a 7.3 with 200k miles on it, replaced the injectors at 165k with single shots and a tune, was amazing until it was stolen a few years back. The thing I miss the most is the sound. Speaking of sound, here’s a 6.0 in a GTR going for the diesel record at Pike’s Peak
https://youtu.be/Ll7nprM1Z8Y?t=1978
I had a stock F-350 with a 6.0 and I had a bad time. Honestly, though, I am unlikely to get another diesel at this point. Modern gas engines are plenty powerful for my moderate towing needs. Maybe if I was doing 20,000 pounds or something, but for 8-10k? Gas has been fine.
As always, the great research and clear presentation never fails to pull me in – I’m not a truck or diesel guy in the least, but really enjoyed it and learned a lot!
The headbolt issue reminds me, on the gasoline side, of Ford’s travails with the 4.6 modular’s spark plug ejection problem. I was lucky and it never happened to me, but had a few friends who weren’t so lucky.
I think the 5.4 was more prone to launching plugs. My 2002 F150 launched one just after I bought it in 2020 and I discovered it had been “repaired” with Dorman’s crappy thread chaser kit instead of solid inserts , and there were 3 more so I have reman heads and no further problems. The 2 valve Tritons can be fixed easily and relatively cheaply. Fix any bad spark plug threads with solid inserts (a Cal-Van kit is about $500, use quality plugs torqued to 20 ft-lbs, Motorcraft coils and cast iron timing chain tensioners instead of the plastic ones.
I had an expedition with the 4.6, the ejected plug was really the only engine issue I had before selling it with over 300k miles. Relatively cheap and easy fix like you said
The injectors had another issue that led to a lot of the warranty claims – Ford tried to match the quietness of the Duramax with its common rail injection system by firing multiple injector events. The HEUI system couldn’t really handle that requirement, and it led to the high warranty costs as the injectors failed.
Ford’s solution was to reflash the FICM to eliminate the multiple events, which made the engines much noisier. A lot of early buyers were upset that their trucks were suddenly as noisy as a 7.3. I remember the forums at the time were full of complaints.
That headline has me going 6. (point)”Ahnaw! Hell naw! Y’all done up and done it”
That video should also be sent to anyone complaining about getting work done on their car and complaining about “labor” costs. Ma’am, adult Legos are not as much fun as you may think they are (but they are seriously fun sometimes).
My 7.3 03 E-350 just crossed 450K miles while hauling and towing 10K pounds of car and parts. If I can ever kill it, I will skip the 6.0 generation
Skip right to the 6.7L (don’t even look at 6.4L)
The 6.4 and 6.7 have never been offered in the van chassis because there’s no physical space left to put anything (mostly emissions related gear)
I had a 7.3 before loved that school bus engine but not the truck around it as it was not taken care of by previous owners and was rusting away though I would like one again at some point preferably a first gen to go along with my first gen cummins. I have a buddy that is a die hard 6.blows fan he always swears by them but always has some sort of issues with his trucks.
I vaguely remember that my brother in law talked to a Ford tech who showed him a massive backlog of Super Dutys with their cabs off waiting for one of many engine repairs or even replacements.
Great read. I’ve driven both, both owned by an old farmer that I helped during harvest for a couple years. The 7.3 was a tank. Noisy, didn’t like cold starts, but unbothered by pretty much any load. It didn’t flinch one time we hauled a 30000lb telehandler 40 minutes on the highway to didmantle a barn. When he passed away the 7.3 had crossed the 300k mile mark and was still used daily.
He also had 2 6.0 F-350s, which honestly were quieter and more comfortable to drive, but also had all the problems associated with 6.0s. The worst was the time I had to replace FICM in zero degree weather. Talk about an unpleasant repair. Both, in fairness, did have over 200k miles, but we were regularly getting stranded in them.
He also had an old F-350 with a non-turbo 6.9 was was absolutely GUTLESS, but somehow it just kept going. It was over 400k miles.
I then drove the van thousands of miles without issue before a team of drug enthusiasts took it upon themselves to turn my van into a “science lab.”
Did they at least offer you free candy?
No, but they did offer me two stolen stereos, my own batteries, and a stolen class IV trailer hitch. lol
Maybe next time you can offer them some free candy. Drug enthusiasts like gummi bears, may I suggest a few pounds of these?:
https://www.amazon.com/review/R2JGNJ5ZPJT4YC
Simply wait an hour or so, then while your new friends are otherwise occupied stroll over and recover your van.
You are evil. And not just go to hell evil, but supervillan level evil. I like that.