My 1997 cadillac deville concours is holding to much pressure in the coolant system and causing my idle to run high, it has a new radiator and theremostat once I releive the pressure every time I drive it the idle will go down but I have to do this everyday
Cooling system pressure is not connect to the idle speed. If the pressure is too high the radiator cap may be defective. If the car is running hot you probably need to have the cooling system serviced.
If you have a Northstar engine the head gaskets may be leaking.
These older Caddies would raise the idle speed up if the sensors detected an overheat trying to move coolant faster through the radiator, and F_O_R is absolutely correct about the cap, it should vent any pressure over it's rating listed on the cap. Replacing the cap would be the quickest way to see if that elemanates the problem, but if it don't then a head gasket test is the next step.
Thanks for the best answer points, hop it was just the cap.
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