I have a 2000 chevy 1500 with a 4.3 liter, it has a trouble code of P0442. I can smell gas outside the vehicle about half way back on both sides of the truck, but it seems to do it more when the tank is half full or better. I pulled the box off to check things out instead of dropping the tank. I don't see any leaks, no sign of moisture or stains at all. I'm thinking the trouble code and the smell of gas are related, I am wondering if the vapor canister check valve could be bad and that is letting vapors escape when there is less headroom in the tank. I have looked at all the hoses and lines from the tank and all look ok, but I don't have a smoke machine to check them. Any suggestions?
Country: United StatesMake: ChevroletModel: Silverado 1500Year: 2000Engine: 4.3
Visual inspection, pulled box off to access top of tank.
Hello, and thank you for letting us help you with your automotive question. This code is for a small evap leak. This can be coming from a number of different areas. Typically it is from the gas cap or the filler neck where the gas cap screws onto. If there is any uneven areas then the cap will leak. If this is fine then you need a smoke test if there is not any signs of moisture around any of the tank parts. It may be a check valve or a vent valve but that is not likely.
wouldn't that be considered a big leak and produce a different trouble code?
Not typically if the cap has any small cracks in the gasket or if the neck has small imperfections. The valves will typically cause a larger leak.
so, would you suggest replacing the cap and the neck to completely eliminate this as the problem
No, unless you know for sure that this is the issue. Otherwise you are just throwing money at it. If there is any doubt that the seal on the cap is not perfect and is not cracked or flattened then replace it first and clear the code. If the problem comes back then have a smoke test done before wasting any money on unnecessary parts.
ok, I will replace the cap and try it. I will get back to you with the results. Thanks. Jeff
Thanks for the reply Jeff. Please keep me posted and we can continue if necessary.
Have a good evening.
It looks like it was the gas cap, the gasket was looking worn and the filler neck had some surface rust on it. I replaced the cap and cleaned the rust off the neck. I have been driving it and so far no problems. Thanks BOBBYSS!
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