HenrikL

My 1991 S2 has some problems with the cooling system. I was driving and saw that the temperature gauge rising, but I got home just when it reached the red zone. Stupid as I am, I opened the radiator cap and lost a lot of coolant.

I have filled and bled the cooling system now following the instructions on Clarks garage, but the car is still overheating. The fans are working at both speeds, but the temp gauge keeps climbing to the red zone.

Before I start looking into head gasket or water pump, I want to make sure that there is no air left in the system. No matter how hot the engine gets, I still have no heat inside the car. Doesn't this mean that there is air in the system? Any ideas on how I can get rid of the air?

xsboost90

jack up the ps of the car as high as you can get it- turn the car on- allow to reach temp- turn the heater on full blast. Make sure the coolant is topped off beforehand, then bleed at the bleeder until no steam is coming out just fluid- dont crank it open just slightly. When done the coolant should be between the full and low marks on the tank. If your heat is not working properly, there is still air in the system. If the gauge when motor is cool is instantly in the red - there is air in the system.

Jfrahm

When I had this problem my water pump impeller had started spinning on the shaft. New water pump, etc. and all was well.

-Joel.

Jfrahm

Also my trick for bleeding the cooling system:

Engine not running, heat on, engine cool or cool enough not to scald you.
Take off the radiator cap and loosen the bleeder screw. Put your palm over the radiator neck and the overflow tube in your mouth (perhaps clean it and dunk it in some clean water beforehand.)
Put a wrench on the bleeder scre, hold in your left hand. Blow into the overflow tube and then close the bleeder screw. Blow again, open/close the bleeder screw. Repeat as needed. Eventually coolant will squirt out the bleeder. You should be able to get nearly all the air out of the system, go for a drive and give it a quick bleed when it's good and hot.

Rinse out your mouth, perhaps with beer, afterwards. Do not swallow coolant, or beer contaminated with coolant.

-Joel.

HenrikL

Thanks! I made a search and found lots of tips on how to bleed. I'll try that tomorrow.

One thing that I don't understand is how I can have coolant at the bleed screw, but not at the heater pipe six inches lower. Must the thermostat open before coolant is let into the heater pipe?

Z-man

Same thing happened to my H2O pump a couple of years ago.

-Z

N_Halbert

You had the over heating problem before you lost the fluid. You need to address that problem first. You can bleed to your hearts content but it may very well continue to over heat and you may faultily believe it to be air in the system. It may be the water pump, as a number have pointed out, or the thermostat.

HenrikL

I totally agree, but my thought was to remove the air first. That way I would not have to worry that the air got in the way when I was looking for the real problem.

I used some of the tricks learned here on the forum to bleed the system again. Today the car seemed to hold the temperature, at least for a short drive, but still no heat inside the car. Strange....

Todd157k

Not strange. That's what happens when there's air in the system.