Over the past few years I have noticed something, it appears that gas caps are becoming difficult to find one that fits. Both my 87s, and my 89 have the original gas tank. A few years back I bought 3 GM gas caps, BUT every replacement cap I have (even the GM ones) do not have the correct thread. It is like they are too large, and the thread is wrong.., they kind of fit if you fiddle and monkey with it, They do not screw all the way down either, so they do not seal correctly, and in some cases leak if you just filled up!!!

The ONLY car that I have a gas cap on right now that fits correctly is my 87 Formula, I can easily spin it on, and then it clicks.

Anyone have any luck with any gas caps? I should take some pictures this evening to show what works and does not work.

John

 

I had the same issue but got one from Auto Zone and it fit perfect. Don't have the part# for it, but I went up to the counter, told them what year my car was. Paid for it, and tried it on for size in the parking lot.

 

I've had TWO gas caps like that. ....my CURRENT gas cap fits great. But yes....I know what you mean, and I agree that they don't all fit properly.

 

Clean the inside of the filler neck, and the threads on your gas caps. IDK, maybe it's because I never drive my cars, or because I have a lifetime supply of caps from working at the gas station. LOL

 

Like Drew said, clean the threads on the neck and the cap, worked for me on an off topic car.

 

The threads are clean as a whistle on the neck and It is a new cap, so I need to either file down the threads on the cap or get another cap.

 

My new one has the same problem....

 

My issue was definitely NOT a dirty thread issue. Not saying that could NEVER be an issue of course, but not with the two I had.

 

It’s OK to fit an aftermarket gas cap with a file.

I wish all not-quite-right parts could be corrected so easily.

 

I bought GM OEM parts by part number and they were all screwed up... I threw on the cap that worked.

 

Most of the "GM" caps have the Stant S logo molded right in on the cap.






Looking on Ebay at NOS caps, plastic caps in the blue/white GM boxes have the Stant S mark too. Getting really whacky, some of the old metal gas caps have the S stamped in them.

Stop at your friendly corner gas station and ask the clerk if they have a gas cap lost and found. I'm just going to spitball here, and say that if you ask 2 or 3 different stores, one or another will probably send you home with as many as you could ever want.

 

Yep, that is the POS I have... Tried to keep my car GM as much as possible, and ended up being crap.

 

I have the top one of the 2 pics. 3 of them.

 

It sucks that everything is pretty much a hit and miss with parts.

 

Keep An Eye Out At Swap Meets For The Early Metal One's.

 

Notice the thread on that metal cap, it is finer than the replacement caps.

 

There was just one on Ebay.. crazy price.

 

I thought I was the only one with this problem,the threads on mine look too thick.I am on my second one from autozone.

 

It's all made in China now. Not surprised they can't make a simple gas cap. No pride in workmanship and no quality control. Anymore, I try to buy used original parts and recondition them as often as possible and you should too. My 89 needs a new gas tank due to loose filler neck and all I read are horrible reviews on the aftermarket tanks and I have no interest in that gamble. My factory tank will come out, go to the local specialty shop and be reconditioned with the filler neck fixed and put back in the car and WILL fit perfectly as it should, I don't care if it costs me a grand. Finding new parts that look, function or even remotely resemble what you take off your older car is an absolute chore. I would rather pay 3 times for something used then new. I'm sick to my stomach of China parts.

Rant over.

 

I have like 3 of the original metal caps incase someones interested ??


Dave

 

Why you guys losing your gas caps?

 

My OEM cap would leak every time I took a hard right turn. Over time, the plastic started warping with age, which made it worse.

Fed up with this, I randomly walked in to an AutoZone in lower Alabama one day and asked for a replacement. The parts guy did the typical type an essay drill and asked me how many doors my Camaro had.

After he finished his auto parts dissertation on his greasy computer, he turned around and disappeared into the labyrinth of parts behind him. Minutes later, he reemerged with a gas gap.

It fit perfectly, and hasn't leaked since.

 

All my cars but the 92s have this gray cap. Not sure when they changed but I've noticed that the black caps from 92s don't fit well in my 89s that have the gray caps.


http://www.ebay.com/itm/82-92-Pontia...sid=m570.l1313

 

I ended up fixing it... Kinda... Took Tony's advise and filed down the threads... At least it screws on now and does not bind on the 2nd thread not sealing... Took about 3-5 min to do. The thing is I do not think it really fits quite right still, but it seems to at least seal. The Gray Cap I have just spins on and then I seal it with a click. I still need to twist and monkey with the new black one...

John

 

I just purchased a new tank from Eckler's with a sump. My original cap would only screw down about 1 turn and start clicking. It was not all the way down where it would seal. I called Eckler's and they could not come up with a solution but they did offer to pay return shipping if I could not resolve the issue. I also took the members advice and got a flat file and started lowering the thread peaks and then used a small round file to clean up the shavings. Not alot of filing maybe 5 minutes including cleaning up the threads with the round file and it screwed all the way down and sealed. gas cap screwed all the way in

 

I have had this problem throughout my car's 28 year life. I replaced about 1 cap every 2-3 years early on and then decided to win the battle. I used the file technique and lowered the peaks in the cap threads. Prior to installing, I added some lubricant to the threads and it went on perfectly. All I do now is add a little "zipper grease" to the cap threads every 6 months or so and I have not bought a new cap in the last 8 years. All of my replacements came from a GM dealer.

 

 

This is probably going to sound kinda stupid...

In my frustration, I took the Stant locking cap from my '93 Corvette, and it isn't tight like the cap I specifically bought for the Camaro.

Is it possible the aftermarket cap for the 'Vette is different?

 

Since this is a third Gen Firebird and Camaro board, I do not know. The threads might be different, larger, smaller,

 

 

I just took my 87 gas cap back and got a 2010 camaro cap and it fit perfectly and sealed great .they looked basically the same when I tried to compare threads but I tried anyways and bam screwed right on.

 

I might give that a shot

 

I had bought a (ACDelco GM Original Equipment GT195 Fuel Tank Filler Cap , Black) on Jan 28th, 2022 for my 1992 GMC truck which my near 80 year old step father on Jan 1st, 2023 crashed into the back another truck in front of the Frosty Freeze. It was light front end damage that I could have easily repaired but I used the wreck as an excuse to get him retired and off the roads. Got him a State ID now instead of a driver license and he is happy as a clam now retired and has never mentioned not one single time anything about not driving anymore.

Anyways I took the gas cap off the truck and put it on my 1992 Firebird and it fit perfect.

 

I hunted down an orig, mine has the part number on it. I had a cheap plastic stent one on that was wrong.its metal, cad plated too. The start one caused issues in the purge/ char canister , that’s how I found out I had the wrong one on.

 

I'm bumping this thread instead of starting a new one. Mine is a 1989 Firebird 2.8 automatic with 70k miles.

My filler neck and gas cap allow fuel to dribble down the side of my car. I replaced my rotten fuel tank last year, and the original cap didn't mate with the new tank. Finding a gas cap to fit my new tank has been a struggle.

I'm still looking, but I will update when I have news.

 

The guys at AZ helped me find a cap that fits my aftermarket gas tank. It was for a 1989 Bonneville and fits great.

Good Luck!

 

I used to just swap the big o-ring when i ran into this issue. Which was usually when the smog guy would tell me my cap was leaking.

 

Here's one I bought maybe 20 years ago that's still in the box. I dug it out when I saw this thread to compare it to my factory cap. Same box as shown above in this thread. Same part number. But completely different cap, nothing at all like my factory cap. But the threads match, and it fits perfectly, although the triangular handle is awkward to turn. It says Motorad on the cap. Here it is compared to my factory cap, which doesn't leak and is still on the car.




The smog techs in CA love to pull that scam. They never replaced mine when I lived there, but they always fiddled around with it. Twist it, turn it, take it off and examine it. Look at me but never say anything. Fiddle with it some more. Look over at me again. They'd eventually put it back on and pass it, but it always seemed like he was thinking about saying something to me, and if I hadn't been watching his every move, he might've tried. But that's a good idea. The O-ring on my factory cap is cracking, but it's still solid and holds pressure.

 

If you look close the Cap on the right the thread is flatter, the threads on the right are more aggressive.