Question about 1999 Cadillac Seville STS

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1999 Cadillac STS Overheating

I Have a 1999 Cadillac STS and it is overheating if i take her out on the highway i have to get off because she heats up to the point where it says to shut down. also if i drive downhill she gets hot but she drives perfectly going up hill i could pull a trailer up hill and she wont heat up!?? shes not using a lot of coolant and no white smoke or coolant smell. the coolant will back up and begin to bubble out of the tank when overheating. Possible thermostat??? I took Her to a mechanic and they told me thermostat, but it puzzles me i also have a 2000 Caddy DTS with the Original Northstar never had a headgasket issue that is almost at 276000 and she still runs strong!!??

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  • Jamal Mohamed
    Jamal Mohamed Mar 25, 2014

    @also Cooling fans come on intermittantly and all the relays and fuses have been checked and are good



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I would have to say ck. the easast things first,when was the last cooling system flush making sure all cooling system parts are clean and new coolant added(old coolant looses its abilaty to work properly when old)then have the thermostat ck to make sure it opens and closes at the proper temp.

Posted on Mar 25, 2014

Testimonial: "Thank you and im not sure about the last cooling system flush the previous owner was not using the dex-cool orange coolant that Cadillac Specifies to use they were using the regular cheap green coolant so i assume that contributed to the issue and i am planning to do a cooling system flush and use a blue devil headgasket seelant to be sure but i just wanted to know before i waste money replacing my thermostat ."


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1999 Cadillac STS OverHeating !!!

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