Gas Cap Woes
#1
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Thread Starter
Join Date: Mar 2001
Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Posts: 14,242
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Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Gas Cap Woes
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
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
#6
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Thread Starter
Join Date: Mar 2001
Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Posts: 14,242
Received 171 Likes
on
125 Posts
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Gas Cap Woes
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.
#9
Supreme Member
Re: Gas Cap Woes
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 wish all not-quite-right parts could be corrected so easily.
#10
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Thread Starter
Join Date: Mar 2001
Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Posts: 14,242
Received 171 Likes
on
125 Posts
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Gas Cap Woes
I bought GM OEM parts by part number and they were all screwed up... I threw on the cap that worked.
#11
Supreme Member
iTrader: (58)
Re: Gas Cap Woes
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.
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.
#12
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Thread Starter
Join Date: Mar 2001
Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Posts: 14,242
Received 171 Likes
on
125 Posts
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Gas Cap Woes
Yep, that is the POS I have... Tried to keep my car GM as much as possible, and ended up being crap.
#13
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Thread Starter
Join Date: Mar 2001
Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Posts: 14,242
Received 171 Likes
on
125 Posts
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Gas Cap Woes
I have the top one of the 2 pics. 3 of them.
#16
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Thread Starter
Join Date: Mar 2001
Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Posts: 14,242
Received 171 Likes
on
125 Posts
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Gas Cap Woes
Notice the thread on that metal cap, it is finer than the replacement caps.
#18
Member
Re: Gas Cap Woes
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.
#19
Re: Gas Cap Woes
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.
Rant over.
#22
Supreme Member
Re: Gas Cap Woes
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.
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.
Last edited by KMK454; 07-27-2018 at 11:08 AM.
#23
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Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Gas Cap Woes
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
http://www.ebay.com/itm/82-92-Pontia...sid=m570.l1313
#24
Moderator
Thread Starter
Join Date: Mar 2001
Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Posts: 14,242
Received 171 Likes
on
125 Posts
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Gas Cap Woes
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
John
#25
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Join Date: Nov 2017
Location: Lexington SC
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Car: 1989 Z28 Camaro
Engine: removed 406 building 383
Transmission: 700R4 swapping to T56
Axle/Gears: Ford 9" 3.70 going to 4.10 or 4.30
Re: Gas Cap Woes
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
#26
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Car: 91 Trans Am Convertible
Engine: LB9 5.0 TPI
Transmission: 5 SPD
Axle/Gears: Posi Rear
Re: Gas Cap Woes
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.
#27
Senior Member
iTrader: (1)
Re: Gas Cap Woes
I have the same issue with a Stant locking cap. Worked ok at first, but after a few months, it got impossible to screw down all the way. I bought a replacement, and it’s now doing the same thing. I hadn’t thought of filing down the threads on the cap...might give that a try.
#29
Moderator
Thread Starter
Join Date: Mar 2001
Location: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Posts: 14,242
Received 171 Likes
on
125 Posts
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Gas Cap Woes
Since this is a third Gen Firebird and Camaro board, I do not know. The threads might be different, larger, smaller,
#30
Senior Member
iTrader: (1)
Re: Gas Cap Woes
I should have been more clear..I removed the cap from my ‘93 Corvette, and put it on my ‘88 IROC.
For some unknown reason, it appears to have resolved the issue. Interestingly, I tried putting the IROC cap on the Corvette, and it wouldn’t fit, so I threw the cap away. Both were Stant locking caps, but I didn’t see a part number for comparison.
For some unknown reason, it appears to have resolved the issue. Interestingly, I tried putting the IROC cap on the Corvette, and it wouldn’t fit, so I threw the cap away. Both were Stant locking caps, but I didn’t see a part number for comparison.
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