Overheating M50

[threlevenguy]

Hey all,

I did a coolant flush on my E30 (M50 head, M52 bottom end), and I'm running into problems with my car running hot. I flushed it all out clean, mixed the coolant correctly, and added the correct amount. However, it starts to run hot and then coolant starts to drain out of the expansion tank hose (the one that gets rid of excess coolant). Is there a bleeder valve or anything like the M20s have? Am I doing it wrong? Pleeease help I need this car to take back to school.

Thanks in advance :),
Matt

[Danny]

Nope, no bleeder valve.

Turn the heater on high, open the expansion tank, start the car and hold at about 2.5k rpms, squeeze the top coolant hose to help move the bubbles, do this until the bottom hose gets warm as well. Then put the cap back on the expansion tank, go for a drive and come back and do it again.

[LannieDuncan3]

I second that. You most likely have some air pockets stuck in the system. If that doesnt work for some odd reason, its possible your thermostat is stuck closed.

[threlevenguy]

So when I do this should the coolant level be full?

[dude8383]

So when I do this should the coolant level be full?

I believe you should be topping it off every so often.

[Adrian_Visser]

I drilled a small hole in my thermostat on the s52, never had any issues bleeding it. If you really have trouble you could try this. The little dot or arrow on the thermostat that goes up is the spot to drill out. Let me re-iterate a very small hole, like 1/16"

[Vtec?lol]

Very small hole and drill/tap with a shallow bolt/screw.