96 cadillac deville overheating

Bad news 01 deville ,head gasket failure .Agin,and agin

Check the waterpump and thermostat. When the waterpump doesn't turn, engine heat is not transported to the radiator. When the thermostat doesn't open once warm the same happens - no engine cooling.

The radiator should be hot op top and cooler at the bottom. If it's cold allover then there's no cooling fluid transport

check the rad and cooling fan on motor also check fan relays
make sure rad colling fins are clean if all this check out o.k.
cylinder heads may be plugged up try reverse flush if it dont help
head gaskets or heads

I'd start with replacing thermostat (that's the most common fault) Other possibilities; waterpump,leaky hose, radiator cap (not holding pressure), fan belt broken. I'd inspect for belt & leaks - if good replace thermostat.

Overheating can be numerous things: Fans not working, water pump, thermostat, overflow cap, and the list keeps going. When the engine is running and heats ups, feel the heat of the top hose, if the hose isn't hot, the thermostat is most likely stuck open and needs replaced. If it is hot we know you have circulation. The cap on the expansion tank may be defective, if it can't hold the pressure of the water, it will release at the overflow cap if the cap is bad. Also check the coolant level.

Your radiator might have a clog and needs to be flushed...also check your water pump to see if its working right.

it is the head gaskets but they have failed because the head bolts have pulled out of the block ever so slowly

remove air filter housing,remove secondary air check valve bracket,if equipped,remove lower radiator hose from the thermostat housing,remove waterpump bypass hose, remove waterpump cover,use special tool to remove waterpump,install a new o-ring inwaterpump housing

Sounds like an overheating problem, best to get it checked, maybe thermostat stuck closed, pluged radiator, head gasget, cracked head.

99 cadillac deville overheating put in new radiator,thermostat,waterpump. it stays cool at idle for a hour running.drivin about 15-30 minutes it overheats. is not using hardly any coolant to speak of.