Mechanics

WHY DOES MY OVERHEATS WHEN IT IS IDLE?

2000 Cadillac Deville • 110,000 miles

When I'm on the highway, the temp. Gauge reads normal and the heat works fine. When I slow down to a stop, the temp. Gauge goes up and and I start getting hot engine display on the dash and the heat blows out cool air. I get out to check the engine when it overheats and the top radiator hose is hot and the fans are running. What could be the issue I am having, and what should I do to repair this problem?
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Budders71
March 3, 2012.



Make sure the cooling fans are working. When you are moving, there is air circulating through the radiator. When stopped, the air stops.

I`m no expert, but that reply was powerful weak

Tiny
Thebuzzer
Apr 6, 2012.
My car did the same thing, but dont worry even if ur cadi overheats it will be fine as cadillac northstars will run 50 miles even after overheating by running 4 cylinders instead of 8 to protect the head gasket. Ok heres wat was wrong with my 2000 deville. The radiator cap wasnt holding pressure and over time this allowed air to get trapped in the heater core. So if u hear gurgling under the dash this is the issue. Simply put the car on ramps or park on incline then take off rad cap when cooled, let it sit overnight then in the morning start the car let it run for 10 min or so with heater on high and repeat as needed. I overfilled the radiator slightly before I put on ramps to help force these bubbles out as this cooling system is self purging so overfilling shouldnt hurt the engine. Inspect the overflow housing for cracks also, but def get the radiator cap tested first and go from there

Tiny
Thebuzzer
Apr 28, 2012.
P.S. Let it run with rad cap off for 10 min then turn engine off, allow it to settle for a moment then recheck coolant level and add as needed. Dex-cool only! Also check the purge hose by the cap and make sure it isnt clogged

Tiny
Thebuzzer
Apr 28, 2012.
Hey may 2000 dts doing something like that I just changed the thermostat and and still says over heating and when I cut the car off the waters boiling inside of the over flow tank. I keep hear ppl talk in bout purge lines by any chance dose someone have a pic of em on this type of car thanks

Tiny
Redman-fla
Jul 25, 2012.
U need to test your coolant for hydocarbons. Get the kit and check it

Cadieman
Jul 25, 2012.
Budders71 if u still have the cadi its definitly a small leak in the head gasket or head and it blows into the engine on the exhaust side so any type of pour in sealant wont work. I learned the hard way. Mine was immaculate other than the overheating and had to sell for a fraction of wat its worth to end the nightmares. Live and learn

Tiny
Thebuzzer
Aug 2, 2012.