Can a wrong gas cap be used?


Will just any gas cap do? The gas cap for my 1990 Toyato Sienna is missing. How critical is it that I buy the recommended (which will take extra work and a drive) to get, or can I just use any gas cap, that I bought at Walmart? Thanks.


You might be okay with the generic one from Wal-Mart, but then again, you might screw up the emissions control/venting system for the gas tank. If you screw up that system, it could be expensive to remedy.

Personally, I would not take a chance, especially since somebody posted a problem a few weeks ago that stemmed from the gas cap that he bought at…are you ready?..

If you don’t want to drive all the way to a Toyota dealer, at least go to a reputable parts purveyor like NAPA.


I agree. I don’t think you need to pay Toyota for a new cap, but I’d go to an auto parts store and get one specifically for your vehicle, rather than a generic cap.


There’s nothing high-tech about a gas cap. Either it fits or it doesn’t. The venting and emission controls for 1990 were not fussy as they are today. Try a generic cap, one that is expected to fit. I would not expect there to be a problem.


I respectfully disagree Steve.

If the cap seal does not seal tightly the CEL will come on.


1990 cars don’t do this. They didn’t yet have the vacuum sensors of recent cars. Note that this guy has been driving without any gas cap and has not mentioned the CEL.


Wal-Mart should sell one that is the right type for your car.


I am interested in hearing more on this.

I bought a locking gas cap for my '97 caravan after someone put sugar in the tank. The dealer recently told me that this was causing the CEL to be on.

However, Chrysler doesn’t make a locking cap. My van does not have power locks. There is no lock on the gas cover at all. We bought our caps at Advanced Auto. ( the little rat b------ also hit my husband’s tank–a 95 Isuzu)


I have purchased all my gas caps at Adv Auto and have had no troubles. I would take back the locking cap, relate the dealer’s statements and request a new one. If that one also sets the check engine light, there may be an issue with the cap itself.

It is possible to purchase locking gas doors that may fit your vehicle. See what Adv Auto has when you are there. You see a lot of trucks around with these doors.