i just joined today i have a 1996 cadillac deville that i have been having cooling issues with for a while and i am running out of ideas haha but i have replaced everything but the radiator and the water pump....i replaced the cap and the thermostat three times and the coolant tubes on the back of the cylinder head. It ran good for a a few months i was able to take it on a 100 mile trip without any problems running 70 to 75 mph and running only 194 to 196 degrees coolant temp the whole way on the expressway and then just recently we had a 50 degree day and it overheated again enough to go into limp mode...i have no leaks and i checked the water pump and it looks like brand new with no leaks all belts are fine and i pressure tested the cooling sytem and it holds fine. no coolant in the oil and it doesent burn it and the day it overheated i went to check the coolant level b4 i even drove it when it was stone cold and it was still pressurized i couldnt take the cap off the reservoir without coolant pushing out ! the bottom radiator hose by the thermostat never gets hot and the radiator doesent get hot on that side just warm. sorry about the run on haha but i like this car and i would really like to fix it any help is appreciated

 

o and heres a picture of the big white devil i mean deville haha

 

take a look at the coolant thread in our FAQ ...
several possibilities exist ..

1. defective pump ..
2. pump with backwards impeller - as dumb as it sounds, there are lots of such pumps out there
3. defective or installed backwards thermostat - pull it and test it in a pot of hot water, make sure is in correctly, coil to the engine block side
4. failed headgaskets .. this would allow introduction of superheated gas into the coolant
5. blocked radiator .. pull it and flush it
6. see the coolant thread for more ideas






.

 

thanks im thinkin the radiator is the culprit