Gas CAP isues

[Heldju]

Hi.
I keep getting the “tighten gas cap” alarm on my 04 Tahoe 5.3 gas. So I figured I would by a new cap as that was supposed to be the easy fix. But the problem is when I try to put the new one on, it only spins like one round before it start clicking. When I look under the cap, it is still like 1/4” from sealing against the gasket. I also noticed when trying to old one it has the same issue.
Do I have the wrong cap? Any one else have this issue?

 

[Doubeleive]

assuming you bought a oem gas cap and it didn't resolve the "tighten gas cap" issue then you may have a evap leak or a bad evap solenoid, there is 2 of them one under hood on the intake and the other is under rear of the truck near the spare tire. Usually the tighten gas cap warning is indicative of a small evap leak which could be the easier cheaper front solenoid they run about $30-35.00 but it could possibly be the rear solenoid and/or canister also, with the rear solenoid running about $50 or so and the canister about a $100.
without paying for a diagnosis (evap leak test/smoke test) it's really hard to say.
one way to tell if you have more of an issue is if it is hard to fill the gas tank. i.e. the nozzle shuts off or clicks off a lot when fueling up or if you have to hold the nozzle with a little air gap to make it fill.
it's kind of a gamble on how to proceed, a lot of people just shotgun it and replace both solenoids and the canister and be done with it. or you could take it and have it tested and end up paying more or the same price as just shotgunning it yourself, or you could try just the front solenoid and cross your fingers, etc, etc.

I would say though to start with being sure you have the correct gas cap, if it is not a OEM get one they are not that much.

 

[Heldju]

Were is the best place to buy a OEM gas cap? There is no Chevy dealers around were I live. There are a few aftermarket dealer, but they buy from Rockauto, summit at shops like that.
If you look at the picture it shows how far in I can get the cap.
The two caps I bought was from Rock and the brand was ACDelco.

 

[Doubeleive]

Were is the best place to buy a OEM gas cap? There is no Chevy dealers around were I live. There are a few aftermarket dealer, but they buy from Rockauto, summit at shops like that.
If you look at the picture it shows how far in I can get the cap.
The two caps I bought was from Rock and the brand was ACDelco.

View attachment 221178

@915_Tahoe can get the last eight of your vin and tell you the correct oem part number to order, or you can call any gm dealers parts department and provide them the vin number

that gas cap looks like it is not the right one at all.
once you have it you can search that oem number on gm parts direct or amazon/ebay, I would be sure to use oem.

 

[89Suburban]

I don't understand it.

 

[Doubeleive]

I don't understand it.

they need the correct part number which is found by looking it up with the last 8 of the vin at the dealer

 

[89Suburban]

I just went through some gas cap drama with my mom's Cavalier last week. Pep Boys gave her some Stant gas cap ************* that was worthless. So I looked up the ACDelco part number on RockAuto then ordered it from Amazon LOL $$$ and it works fine.

 

[915_Tahoe]

Were is the best place to buy a OEM gas cap? There is no Chevy dealers around were I live. There are a few aftermarket dealer, but they buy from Rockauto, summit at shops like that.
If you look at the picture it shows how far in I can get the cap.
The two caps I bought was from Rock and the brand was ACDelco.

View attachment 221178

whats the last 8 of the vin# i can get you the correct part#

 

[Heldju]

Here you go

4J311821

 

[Joe Collins]

I got an OEM one from Advanced auto parts and still have the same warning. I just replaced the evap canister a year ago seems odd it's bad again already but I'm getting the same warning and CEL saying to check evap