: could this be anything else?

03-31-08, 09:35 AM
my 2000 deville is overheating after about 15 mins but im not losing any antifreeze from what it seems.....i changed the waterpump and the t-stat the bottom hose goin to the radiator seems to be staying kinda cold or atleast not as hot as the rest i changed the t-stat twice already. everyone is telling me its the head is most likely the casue and that its getting presurized but i have no other signs of head failure. is there anything else it could be??

03-31-08, 09:55 AM
Is the thermostat facing in the correct direction ? If you're not overheating and blowing coolant out the pressure cap then it wouldn't appear to be a head gasket. The only sure way to find out is to have a coolant sample test done by a dealer or radiator shop. You can also buy a test kit at some large auto parts houses. There's 5/8" a purge line going from near the thermostat housing to the upper side of the surge tank. With the car cold and the cap off, does the purge line spit coolant when you start/idle the car ? If not, it's plugged and the system is probably airbound somewhere. .......and, is the water pump belt and tensioner in good condition and functioning properly ?

03-31-08, 10:26 AM
i am overheating the belt is spinning and the tstat is the right way

03-31-08, 10:28 AM
if the head was bad wouldnt i be losing coolant from the overfill......is the surge tank the same as the overfill?

03-31-08, 10:47 AM
Re: submariner - Check purge line. If you're concerned about the head do a coolant check. It will confirm combustion gases in the coolant or not. K_C

03-31-08, 10:58 AM
the only cause for gases in the coolant is the head?

03-31-08, 12:00 PM
Yes. The coolant system is sealed. You should not see any loss and you're not. HG failure typically leaks combustion gases into the cooling gallery, also pushing coolant out of the system overflow. No other way the gases can get there, thus the value of testing. You can also check cylinder compression, but as a first step the coolant check seems like a quicker and easier option.

What symptoms of over heating are you having? As sub pointed out, could be air lock. Check that purge line while you tackling the coolant test. Both DIY tasks. K_C