I just bought a 99 seville couple weeks ago and this is my first cadillac, and its been nothing but a pain. rear window actuator and motor are missing (easy fix), trunk fills with water when it rains, needs motor mounts, overheats (replaced t-stat, waterpump, presure tested no leaks, so now im probaly looking at a headgasket) ..... SO now the problem of the day im getting a service engine soon light, and the display says check gas cap. could this really be as simple as replacing the gas cap? has anyone had this problem? Thanks for any help.. also any ideas on how long i can keep drivin this thing with the headgasket screwed up I cant afford to fix it now. THANKS!

 

Check gas cap message displays when there is an EVAP system leak. It really wont hurt drivibility. Check condition of filler neck and seal on cap. Driving with blown head gaskets is not recommended. Have repair shop run CO test on cooling system to verify it head gasket is blown.

 

Thanks for the fast reply bro, im gonna check that in the morning. Im sure that it needs a headgasket cuz i got steam wish i would have seen that when i bought it it was cold that day so i didnt even pay attention to it. Ive done head gaskets before on older vehicles, but im scared of this motor i hear i have to mill the heads or it will leak again and i saw a post about head bolts stripping. and thats gotta cost a fortune...

 

A bad slug of gas could have gone through. Wait until your tank is empty, refill it, drive for a while, and see if the check engine light goes off. If that doesn't work, disconnect the battery to reset it, and see if it comes on again.

The head gasket could cost thousands of $ to replace, so you should try a sealer first. Bar's Leaks Head Gasket Fix is an easy one to use, and costs about $35.

 

Problem cleared up with the gas cap light just unhooked/reconnected the battery . Still got steam from the exhaust though, ran bars leaks head gasket fix through it didnt do anything... I didnt think it would but figured what the hell got nothing to loose. I really dont want to pull this motor, and the thought of having to drill out the block 4 threadserts really freaks me out.

 

Aric..
Are you loosing coolant, do you have to top it up ?
If not then its possible your head gasket may be ok. Its still quite cold out so the steam you see may be just condensation.
Does it also smell ?

If your lucky the over heating could be caused by a plugged hose somewhere. You said you had a pressure test; but I dont know if that would detect a clogged coolant line.
Who knows ....maybe you will get lucky...so to speak.....

 

Naa I smell coolant, needs topped off every few days, and if you put your hand to the exhaust you can feel the steam in any weather.