How I’d Fix That Toyota That Sat Underwater For 13 Years

Just over a week ago, a man went fishing in Hughes Landing, Texas, and via fish-finder discovered a truck on the bottom of the lake. Authorities in Texas then sent down divers and brought the two-door Toyota Tundra back from the deep. After apparently spending 13 years under water, the truck looked surprisingly good.  That got us (and many of you!) wondering—could this sunken treasure truck be brought back to running order? How would you even go about that? Here’s how I — an engineer, but not an engine builder — would fix it.

Now, obviously, this would be complete folly. A single dunk underwater is often enough to total a vehicle, to say nothing of leaving it underwater for over a decade. Any serious attempt to get such a vehicle operational again would just involve stripping it down and replacing just about every component on it. But that’s not what we’re about.

Instead, we’re taking the shadetree approach. Imagine it this way. Your cousin’s butler’s dog-walker has shown up to yours on a Saturday afternoon with a dripping-wet Tundra on a trailer, and a cooler full of soda and sandwiches. Will you help him try TO get the Tundra running again, just for a laugh? Sure you will!

Your mission, if you choose to accept it, is to restore this truck.

First Steps

Knowing the vehicle has been submerged for an extended period of time, your first job will be to get the water out of just about everywhere. You’ll be pulling drain plugs on the engine oil pan, the differential, and the transmission, and the fuel tank if there is one. Undo the radiator hoses and let everything out, too [Editor’s Note: There’s a slight chance that the cooling system is actually completely intact, with no water contamination whatsoever. It’s sealed, after all! Gearboxes, though, while sealed, have vents to allow for thermal expansion of gases, so they’re not completely sealed. Either way, after 13 years, it’s probably all been water contaminated, so you should drain it anyway. -DT]. Similarly, you’ll be hunting for rubber plugs on the chassis as well. Just about every cavity will be full of muddy brown liquid, and you need to get it all out. Remove the battery at this point, too. Then go ahead and power wash the whole engine bay. Do the whole truck while you’re at it.

Similarly, the interior has to go. There’s no point trying to work on a truck with stinking, rotting seats. They’ll just fill your garage and your lungs with mold spores and take you out before you can even think about getting the truck started. The carpets need to go too, and don’t forget to remove the glove box and dump out any fish swimming around inside. The caveat is that a truck like this Tundra has airbags all over the interior, including in the seats. You’ll need to learn how to remove them safely and otherwise handle them before diving into this.

Speaking of the engine specifically, it’s almost certainly full of water internally, too. You’ll want to undo the oil cap and the spark plugs, the oil filter, and probably the intake and exhaust manifolds, too. It’s important to get water out of the cylinder bores and just about everywhere else. A suction pump is useful in this case, allowing you to suck out any water that’s not supposed to be there. At this point, it’s worthwhile to take an inspection camera and look inside the cylinders. There’s every chance they’ve rusted to the point where the engine is unrecoverable. It doesn’t take much damage to the bores to ruin any chance at the pistons making compression, after all. Also take a look inside the valve covers—if they’re full of mud, you’ll need to remove them and wash all that out.

If, by some miracle, the engine isn’t completely trashed, you can continue. You don’t want to turn the engine at this point, even by hand. Instead, it’s worthwhile injecting something into the cylinders to clean them out a bit and help free up the pistons and rings. Some swear by automatic transmission fluid (ATF) for this job, others like to mix it 50/50 with acetone. Marvell Mystery Oil is also a popular choice for freeing up a stuck engine. Others swear by the acidic benefits of white vinegar, with the idea that it can remove a layer of corrosion and free parts up to move freely. Uncle Tony’s Garage tested a number of solutions on YouTube, which makes a good starting point for your own research.

Uncle Tony’s Garage trialed a number of common solutions for freeing up a stuck engine.

With a healthy dose in each cylinder, and probably some on the valve train, too, the solution needs to be left to sit to do its work. Ideally, it’s best to leave the engine for a few days and move on to tidying up other areas.

Oh, and speaking of the manifolds, you need to check them out. They could be full of mud or otherwise clogged with algae or other marine life. In particular, you’ll need to clean out both intake and exhaust and make sure they’re both free-flowing and not blocked or otherwise caked-over. Oh, and rinse the airbox and throw out your air filter, and get a fresh one for later.

Getting an engine running after it’s been underwater is no mean feat, let alone a whole car. 

More To Do

Okay, so you’ve dumped out all the interior and you’ve drained most of the fluids. Now it’s time to think about electronics. Start pulling apart connectors for inspection. If they’re all green and furry or the contacts are just falling apart, you’ll have a bad time. Corrosion’s a killer like that. Even one dodgy sensor signal can throw off the engine from running properly, so you’ll probably want to source an entire engine loom from a junkyard. While you’re there, try to grab the ECUs from a truck with the same engine/transmission combination. In fact, grab every module you can. While companies like Toyota do try to seal their engine control units and other electronic modules from water ingress, they’re not designed for over a decade of continual submersion. Every electronic module is probably full of water at this point. There’s a freak chance that hasn’t happened, and that much of the loom is fine, in which case, you’re free to leave those components as is. It’s just incredibly unlikely, is all.

The fuel system should be your next port of call. Removing the fuel tank is probably a good idea, so you can give it a good old clean. Ideally, you’d replace the fuel pump, but do the fuel filters at the very least. For a port-injected vehicle, if you’re tricky, you can sometimes try manually running some fresh fuel through the injectors to see how they’re firing. It just takes a little creativity to set up a rig to do so. However, for modern direct injection engines, it’s much harder. You’re probably best placed just sucking any water out of the fuel lines and crossing your fingers.

Now, let’s assume you’ve left the engine to soak with ATF or Marvell Mystery Oil in the cylinders for a day or two. It’s time to see if that sucker will turn. Generally a socket wrench or breaker bar on the crank pulley bolt is the way to go, so you can try and turn the engine by hand. It’s important to remember to turn the engine only in the direction it normally turns. If you’re lucky, the engine will have been freed up and will rotate. If so, you can turn it through a few revolutions to get things moving nicely, and move on.

Of course, it bears noting there’s every chance the engine is moving freely because the rings have completely rotted away and there’s no compression to speak of. If you’re hearing metallic tinks or clunks as you rotate the engine, it’s probably an anchor at this point, and you should snag a new motor from the junkyard. [Ed Note: I’d just grab a whole parts truck from the yard. -DT]

But let’s assume it’s rotating okay and it’s not giving any signs of complete and total destruction, by some miracle. To avoid hydrolocking, you’ll want to suck out any fluid remaining in the cylinders, and then reinstall a fresh set of spark plugs. The later-model Toyota stuff uses coil-on-plug ignition, so you might need to replace those too. Their connectors are probably corroded to heck after 13 years underwater.

[Editor’s Note: I personally would not bother with removing plugs or vacuuming fluids out; the first step would be to just yank the motor out. Then I’d tear it COMPLETELY DOWN and have it dunked in a tank of cleaning solvent; honestly, I’d have a machine shop do the cleaning, because a grain of sand left in the engine is too high of a risk. In the process, the heads would come off, I’d look at the bores. If they looked salvageable, I’d clean them out, line them in ATF, and try to extract the pistons somehow without screwing things up worse. After everything came back from the shop all cleaned up, I’d hone the bores, reinstall the pistons with new rings. I’d take the rotating assembly apart and replace the bearings and probably have the crank ground a bit; it might be so bad it has to be replaced. I’d mic the crank, and check every clearance — rings, bearings, etc. to make sure this thing was ready to fire. -DT]. 

Your next job is to start putting things back how they should be.  Now’s the time to do one more flush of the coolant and oil systems, before refilling them in preparation for your first starting attempt. Throw the airbox back on and put in a fresh air filter. You’ll probably also want to refill the transmission (changing the filter in the process if it’s an auto) so it’s not damaged from running dry. You can leave out refilling the diffs at this point, as you’re just trying to see if the engine will run. [Ed Note: I’d completely tear that transmission apart.It’s gonna have so much silt in it, there’s no chance it’ll work properly. -DT]. 

With all that done, and assuming you’ve safely dealt with the airbags, you can go ahead and hook up the loom and ECUs you grabbed from the junkyard. This is a big job, and on a modern truck, it can require some attention to detail. Most notably, the ECU is going to need a signal from a legitimate key before it even tries to fire the engine. In that case, you probably want to have grabbed the keys and ignition barrel or other relevant components from the same junkyard truck you snagged the engine computer from. And while you’re at it, probably the dash cluster, too.

First Start

Once you’ve worked over the engine, topped off all the fluids, and effectively given the whole truck a loom transplant, you’re ready to try to resurrect the thing. Fill up the tank with fresh gas, and hook up a battery. Turn the key to the “On” position—not Start!— and see what you get. Ideally, you’ll see some life on the dash, with the typical lights showing. You’ll also be listening out for the whirr of the (new) fuel pump as it primes the empty fuel system. You might want to switch the ignition off again and back to “On” to get it fully primed.

Now, it’s time to turn the key for your very first start attempt. It’s likely you’ll have to crank longer than expected to get fuel all the way up to the rail, so don’t be discouraged when it doesn’t catch instantly. Ideally, you’ll hear the characteristic chugga-chu-chugga-chug as the starter fights the compression of the engine to try and turn it over.

At 17:35: this is what you want to hear when you start the vehicle. The rhythmic, varying sound of the starter motor straining against the compression of the engine. If it just runs with a constant whir, you’ve got no compression at all.

Meanwhile, If the engine just turns over with a constant whirrrrrrr then you’re lacking compression. Most likely, the valvetrain is damaged or the rings are shot. Do a compression check and use a borescope to look for trouble, but if this happens, the engine is probably toast. It may even be beyond a rebuild after so long underwater. [Ed Note: You really should never get to this point. When you remove the engine, you should check the bore, check the bearing clearance. You should never install an engine that you aren’t sure will run. -DT]. 

Let’s imagine, though, by some miracle, the engine does appear to have compression. If it doesn’t catch after 10-20 seconds, try to figure out what the engine is missing. Is fuel getting to the rail? Do you have spark? Is there air? If you have these three, and in the right timing, the engine should ideally run. If you suspect a lack of fuel, try spraying some starting fluid into the intake. If it starts to catch, that tells you that you’ve got spark and air at the very least. Further investigation into a lack of fuel or spark would involve checking connectors and sensors and pulling codes from the ECU to see what it can tell you.

If the engine does, by some wonder, actually run, you’ve pulled off a crazy feat. It’s probably running pretty poorly by virtue of corrosion damage to the cylinder bores and the like, but the fact you got it running at all is wild. Before you take it for a drive, though, you’d want to do a little more work. Flushing the power steering system would be key, along with flushing and bleeding the brakes and checking their operation. With that done, you’d want to make sure transmission fluid is circulating properly through the auto and transmission cooler as well. Then, you might be able to take some tentative steps towards driving the thing—but get some fresh tires first!

Reality Check

A few of us had spitballed about getting the stricken Tundra running again, but I hadn’t thought in detail about the matter until it came time to write this piece. As you might realize, it’s a job of massive proportions that involves going through almost every aspect of the truck. Even if you do all this work, you could end up finding out the thing is beyond repair at any point along the way. Succeed, and you’re still left with a vehicle with a questionable engine and transmission and no interior to speak of.

That’s not to say I wouldn’t want to try, given the opportunity. Furthermore, I’d rate the chances of success as far higher for an older truck left sitting on a lake bed. If you go back to the carby era, or an old diesel, there’s far less wiring to worry about, no airbags, and no coded keys or other fancy computer gremlins to cause problems. You could pretty much just take apart the fuel system and ignition system, replace the parts that have corroded away, and reassemble them. You could even hotwire the thing, eliminating the need for an ignition barrel and a key. It would be a lot less work, and you’d be more likely to succeed.

In any case, it makes no sense to try and restore the sunken Toyota Tundra. It would simply take too much time and too much money. And yet there’s something so compelling about it. I’ll dream of wrenching tonight. Meanwhile, tell me how you’d tackle this job in the comments.

Image credits: Woodlands Fire Department, Montgomery County Sheriff’s Office, MR HO THANH CHE via YouTube Screenshot, Lewin Day, Autozone