How GM Ruined Air Filters On The Chevy Vega

There are plenty of automotive wear items that are expensive to replace. As far as engine air filters are concerned, though, they’re usually pretty easy to change, and cheap to boot. But what if they were more expensive and annoying to deal with? If anyone could pull that off, it would have to be the Germans, right? Only, this time, it was GM!

This historical misstep comes to us from Rare Classic Cars and Automotive History, a YouTube channel that chronicles interesting car tales from long ago. The channel has recently been diving into some of the more questionable air cleaner designs out there.

As it turns out, one of the most egregious examples comes from a GM product that bathes in infamy. I speak, of course, of the accursed Chevy Vega.

If It Ain’t Broke, Definitely “Fix” It

The Vega was an important car for GM. The company needed a subcompact vehicle to grab sales in what was fast becoming a critical and competitive segment. Development began in earnest in the late 1960s,  with the car entering production in 1970 for the 1971 model year. Ahead of launch, GM Vice President John DeLorean talked a big game and promised a car with exceptional handling, exceptional acceleration, and exceptional quality.

As we’ve previously discussed, the Chevy Vega was pretty much none of those things. Rust issues, assembly issues, and all manner of other foibles quickly came to the fore when the model hit the open market. DeLorean would later admit that his boosterism was misguided in his book, On A Clear Day You Can See General Motors. “While I was convinced that we were doing our best with the car that was given to us, I was called upon by the corporation to tout the car far beyond my personal convictions about it.”

There’s one flaw to the Vega, though, that is seldom discussed— mostly because it was overshadowed by all the other problems. It’s the air cleaner. GM found a way to make a commodity part more expensive and annoying for the customer. How? By integrating the filter and its housing into one overly complicated assembly.

Back in the 1970s, the vast majority of cars used the same simple design. On top of the carburetor would sit a round two-piece air cleaner housing. You’d undo a wing nut, take the lid off the housing, and inside would sit a round paper air filter. You’d pull it out, put in a new one, reinstall the lid, and you were done. There were only a few sizes of these round filters, and just about every auto shop had filters to suit most every car on the road.

For some reason, GM didn’t want to go this route on the Vega. Instead, it decided to put the paper filter inside an unopenable metal housing. The housing was still made in two pieces, and was pretty similar to a regular air cleaner design, but the top and bottom were permanently crimped together to enclose the air filter element inside. This assembly then bolted onto the carburetor directly.

Thus, when you wanted to change your filter, you weren’t just throwing away and replacing a cheap paper filter. You had to buy the whole metal air cleaner assembly and change it out as a unit. This made sourcing a filter far more painful. Instead of grabbing any old round filter of the correct size off the shelf, you had to get the specific AC brand part for the Vega. AC would become AC-Delco in 1974, streamlined to ACDelco in 1995.

This was an unpopular decision and a confusing one from an engineering standpoint. Enterprising owners and mechanics did find a workaround, however. The popular move was to pry or cut open the sealed filter housing to turn it back into a two-piece unit. Then, it could be used like a regular air cleaner housing, with the paper filter inside changed like any other. However, there are some reports that the original paper element was glued inside the housing and removing it required scraping off some residue afterward.

The aftermarket also offered a nice alternative. Companies like Fram sold their own two-piece air cleaner housings that could be installed in place of the original. Once installed, further filter changes could be handled in the usual manner.

The service manual for the Vega stated the air cleaner should be changed every 50,000 miles, or every 24 months—whichever came first. More regular replacement was recommended for heavy-duty use or dusty conditions. It was a strangely long service interval for the era, which took some of the sting out of the price—it meant dealing with the problem was a regular but infrequent headache for owners. One YouTube commenter notes that sticker shock was common back then. In the 1970s, when a regular air filter might cost $5 at most, the Vega’s air cleaner assembly could cost three to four times as much. In an era that was economically quite turbulent, this was surely an unwelcome additional expense for some owners.

Why did GM do it? The most likely theory was that it had to do with the grand cost-cutting effort that defined the vehicle’s production. GM was chasing wild savings in the Vega program. It even famously figured out how to ship the cars vertically to fit more vehicles into a single train carriage to save on transport costs. In the case of the air cleaner, the all-in-one design would have simplified assembly, speeding the production line to some greater or lesser degree. Normally, the operation would take four stages—install the air cleaner base, then a filter, then the lid, and finally a wingnut. Having a single-part air cleaner with an integrated filter would reduce this to two operations—put the cleaner on, and tighten the nut.

In any case, the Vega’s design thankfully didn’t become a widespread trend in modern automobiles. Most cars on the market will let you change an engine air filter element directly and with a minimum of fuss. In this very specific way, pertinent to air filters only, we’re very lucky to be living in an era as blessed as this one.

Image credits: GM, eBay,