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Fuel Additives in Newer Cars

My 79 year old father put fuel additive in his 2010 Chevy Impala. Don’t ask me how much, or for how long… The Check Engine light came on. I never got a clear answer from him on what his mechanic said about it. Five to Ten fill ups later the Check Engine light went out on its own. Engine seems fine. Could this have caused damage to the engine or emissions controls? Would a computer diagnostic from a mechanic pinpoint any problems? Would you recommend a computer diagnostic be perfomed?

Commercial additives, like, say, Techron, won’t hurt anything. It’s more likely the gas cap was loose.

I would want to know why any CEL (Check Engine Light) came on. Was the CEL flashing? If no then it is likely not important, but if flashing, then worry.

If the light is off and remains off I’d just let it ride. You can have the “codes” read for free at an AutoZone or other parts stores (many do this for free now). The codes won’t tell you much and since the problem is not causing the CEL to come on it likely was self limiting. A loose gas cap is commonly a cause of CEL to come on.

As for the additive, without knowing what it was, or how much was used it isn’t possible to give you an answer on that. If the additive was a fuel additive (not for transmission or radiator or something else) I don’t see a problem. The fuel additives I’ve seen say that you can use more than the required amount and do no harm.

@Badger63 - What the additive was is the key question, folks in years past have added all kinds of odd stuff to their gas, some of which will cause problems - any way for you to find out?

Even though the CEL has gone off, the code that tripped the light is held in memory…I bet the code had nothing to do with the additive…As Turbo suggested, you can have the computer scanned for free…

I’d have the stored codes read (if there’re any) just to be on the safe side. Post them here and we’ll fight over them.