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1999 caddy deville overheating

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1999 Cadillac Devilleis overheating sometimes so I figured the thermostat is sticking there is coolantthere is no  oil leaking don’t think it’s a gasket I think it’s gonna be my thermostat my question is how do I remove the thermostat I know it’s under the breather do I need a special tool I am a little mechanically gifted for a girl

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Things to that when I say overheating it doesn’t necessarily go above 205 to 210 but I know that’s hot for my car my car is usually running around 190 could it be that I don’t have the coolant mixed right I didn’t know you had to mix coolant and water distilled water so I need to drain half of it out and mix it 50-50 right

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Around 210 is normal operation temp.

Was the coolant you bought  premixed or 50/50?

It will be posted on the label............

If so no need to drain any out.

Even if it WASNT pre-mixed it will be fine also because it will be diluted by the

existing antifreeze/coolant in the car.

Your car should be Dex-cool anyway.

Dex-cool should be pre-diluted anyhoo................

93 DeVille-13 Chevy Impala

72 GTO - 77 Triumph Bonneville

84 Z-28

Syracuse NY

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I am sure this will be debated, but here is what I can help with.

What is the average outside temp when it is showing around 210? This plays a factor.

If age of coolant is unknown it needs to be changed asap. 

My 2 run 196 all day long. Unless I am sitting hot in traffic, (rarely)

A few important things to check. 

Water pump tensioner. This is a big one. Driver side of the engine just below the black bracket next to the cam cover. Inspect the small belt. Move the tensioner with a 1/4 ratchet. If it does not move easily I would replace it and the belt. Poor belt tension makes the pump slip under load.

If you want to replace the thermostat it is cake. It is located on the water pump housing. 2 bolts hold the steel housing onto the water pump housing. Just follow the hose on the driver side.

It bears mentioning to have a smell of the coolant surge tank. If it smells anything like exhaust you may have bigger issues, but from what you are saying I am not even going to entertain that yet.

As for the coolant, there again if unknown age, condition, mix, etc... Just drain it out and put a proper mix of premixed antifreeze, (easy), or antifreeze mixed 50:50 with distilled water.

The coolant is supposed to be Dexcool. They are sold straight or diluted. I run Global in my Deville. I change mine every 2 years regardless of what coolant I run. I have done it for years and have been trouble free



Nice, clean, luxury= fine automobile

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