I mirror the above comments.

i agree with semtex as well. I had 2 dealerships mess my cobalt up cuz of spark plugs, they put in the wrong type, fried the o-ring on the valve cover and oil went all over the place and engine wouldnt start. I guess all u can do is try flushing that crap out and then put in other oil. Only thing i can think of, why the CEL would come on is maybe it didnt lube up a part good enough and something went wrong or maybe its not cooling parts good enough. Or could be something simple as in they didnt tighten a bolt or maybe the dip stick came out. Cobalts had a bad case of dipsticks poping out and it causes CEL to come on.

I usually get the first, oil change at the dealership on a new vehicle. Just so that if I ever make a warranty claim they can't say **** about improper regularity with my changes. After that I do them all myself. I also save the receipts from my oil and oil filter purchases with the dates printed at the top and write down the milage on them at the time of the change. I've never had to have warranty work done on a engine but in the event I ever had to I wanted to have as much information I could about previous maintenance available to me.

I know this isn't the dealer, but it goes along with the same reason why I never trust anyone to work on my car. When I can't do the work myself, I usually go to great lengths for proof of work done:

busted!

Either do it yourself, or sit there and watch the mechanic. If I drop my car off, I do not leave my car's side the entire time they do something. It's worth the extra time and effort.

And all of this happened in California. I thought they were supposed to be all about peace and love out there :icon17:

John

I love zmax I have used it about 3 times in my civic with no problem works great.

Did it help your sound system with all the bass and treble, in some wacky liquid form?

Works great...what kind of testing have you done?

lol since when was california designated to be the state of peace and love?

i have a pretty good background in automotive tech. and its amazing seeing and hearing all these things that happen. i myself have fun with it.. i like to pretend i dont know a thing about cars, so that if a certain mechanic tells me i need some bs done i just get in my car n leave. i understand theirs times when u cant perform a certain service on the auto so u take it to a "professional" to get it done, but the best thing ppl need to do is get educated and stand up for themselves. ppl need to realize theres always gonna b that person trying to make that quick buck.

They say Mineral oil is good for intestinal regularity too......:ugh2:

Synthetic or Dino?

:icon18: Good one.

Take the car back to get the CEL diagnosed. If I had to guess it could be the following:

- sometimes they check the air filter during oil changes. If they didnt put it back in properly or close the box right it could trigger the CEL. Also, one of the hoses might have gotten knocked off in the process.

- The PCV valve is sucking up fumes from the ZMAX they put in and its triggering a weird reading in the O2

- Guy didn't fully put in the dipstick or tighten the oil cap causing a slight vacuum leak. On some European cars (VW) the car won't even idle if the dipstick isnt fully inserted allowing air to come in.

Also tell them not to put in the ZMAX next time. If you feel like pushing it, ask them to drain it out again but the problem is those oil additives stick to the metal and dont always drain out fully.