The car is overheating, the radiator and termostat have been replaced, and stil over heats. the car is 1999 cadillac seville 4.6 nothstar engine

engine have back pressure that cause overheating or engine runs hot. could be, ( yes, cylinder) the piston rings. but the cooling system is the other system you have to look into. check the engine thermostat, if found faulty, replace it.

You should have the computer checked for trouble codes next.

Wrong thermostat ? You need a 195 Did you replace the coolant sensor ? This runs the fans Run the engine, wait until the engine heats up, if the fans do not turn on when the temp reaches 195, you have a blown coolant sensor, defective relay, or bad thermostat

Check for a bad seal in the radiator cap on the reservoir. Or the cap can be loose as well causing this delimma

how many miles are on it? if you have over 70k the head bolts may have let loose and allowed the head gaskets to leak they all do it

You may need to change out your 94 wiring harness to a 99 to handle electronics not found on you 94 but yes is should work if your computer can (TALK) to your 99 engine

Might try a fix with gorilla plastic mend or jb weld before buying a new radiator

maybe the water pump wasnt the problem to begin with. if the engine temperature only goes up when you stop the car then most likely it is the FANS that are not engaging to cool the radiator which is a problem with the fan sensor, computer that controls the fans, relay/fuse. I had the same problem on my 1999 cady STS coming back from my vacation. the engine temperature would be normal only when I drove the car above 70km/hr because the air passing through the front of the car would cool the radiator. when I slowed down the fans wouldnt start and no air was passing through to cool the rad, hence the engine temperature would start to go to HOT. good luck.

hello i have a 1998 cadillac deville course. an i been having the same over heating problems with mine i been taking it to mechanics an no one seems to know even the caddy dealship its overheating i checked the termostat water pump radiator all hoses was wondring could you tell me what you did or what you are doing to fix your problems my email is [email protected] thank you very much

My retired uncle has a 97 cadillac deville sts that runs well but after a short distance or time idling begins to overheat. He has replaced the water pump, thermostat and had the radiator and head gasket checked. Unfortunately he lives in a rural area and there is no local cadillac dealership for diagnostic repairs.