Weird cooling system problem

[sc2095]

I helped my friend replace his waterpump on his 93 SC2 yesterday, cause it finally died. We filled the system back up with water and coolant, and then let it run to check for leaks. It was working perfectly. We went for a drive, and noticed that the car started to heat up, and wouldn't cool back down. We took it home, and everything seemed ok, but when the car was cold, he took off the coolant resevior cap, and coolant came running out of it. He filled it back up to the lower level, and then went for a drive again. The same thing happened, only it took longer for the engine to heat up. Any idea why this is happening? The thermostat is opening up because both radiator hoses heat up and he has lots of heat in the car.

[SLeepr]

A few questions. How hot is the car getting when you guys are driving it around? The system is pressurized so it will spew coolant if you take the cap off too fast.

Did you check the all the hoses for a collapsed hose? Does the fan turn on when your temp needle reaches the 3/4 mark? When's the last time you changed the ECTS?

[94sc295sl2]

start the car and let it run with the radiator cap off until it gets hot. sound slike you have a ari bubble in the system

[amazinghl]

And DO NOT put the cap back on until the engine is COLD!

Did you also change out the thermostat?

[wolfman]

Saturn cooling systems are self purging...it's NOT an "air bubble" Either the water pump taint pumping, (it's new so unless the belt is slipping horribly..unlikely) the radiator is internally clogged or externally blocked airflow wise (put a piece of carboard or? to protect it while you were working around it?) or the thermostat IS sticking shut. My money is on the thermostat. NOTE: The heater WILL get hot water (produce heat) LONG before the thermostat opens...it's designed that way. It IS possible for the upper and lower radiator hoses to be warm and the thermostat to still be stuck fully or partially closed.

[sc2095]

I think it's on the original thermostat, and the temp will increase all the way to the red mark, until the fan comes on, then it just stabilizes really high and doesn't come back down until you shut the car off. The temp goes up quicker with faster car speed.

[amazinghl]

Change it.

[wrg813]

Originally posted by sc2095
I think it's on the original thermostat, and the temp will increase all the way to the red mark, until the fan comes on, then it just stabilizes really high and doesn't come back down until you shut the car off. The temp goes up quicker with faster car speed.

Fan coming on with temp gauge in red, sounds like the fix all ECT sensor is not reading correctly. Just a thought.

[Bill Murray]

IIRC you can get an OEM stat & ECTS for about 20 bucks total.

[TedL]

Originally posted by Bill Murray
IIRC you can get an OEM stat & ECTS for about 20 bucks total.

Better make that $30; $18 for the t-stat, $12 for the ECTS>

[Qlara]

I'd also check the correctness of coolant-water mix-ratio.....

Maybe too much water in the coolant? Typical mix should be 50/50 (water/green) and some extreme weather may require 30/70 or 20/80.....depends.

[lpkortuem]

Wolfman is right! Saturns purge air very quickly through the Small lines at the top of the reservoir. You might consider that your friend got the thing hot at the time he discovered the leaking pump and it now has head or headgasket troubles. I'm assuming that before he got into the water pump trouble thing that it was acting normally.