Some serious overheating issues

[pushpins]

My 520iA overheats after replacing both thermostat and waterpump. I took out the thermostat to see if i got circulation, and i do. All hoses and radiator is hot. The temp hits red if the car idles for a bit, but goes back to about 1 oclock when i drive it with high speed..

Cant see what else is wrong. No white smoke, no water in oil og oil in water. It doesnt use water or oil.

The only thing i can put a finger on is that the radiatorfan doesnt change speed when engine is hot. I goes around slowly.. But with high speed and no thermostat the engine should get cold either way, right?

Please help, i have read other posts, but cant get a solution.. Its a 90' 520iA with m50b20 engine..

Ingard - Norway

[Whackamac]

Does the 520's water pump have the plastic impeller? I would check that as I have heard they tend to "spin" freely when they fail, not allowing water through the system...

It may be on it's way out in your case which is why it will cool down when you drive.

[seech]

Your radiator fan clutch is probably not working well. Would suggest changing it and also checking if your aux fan is working at both high and low speed.

If travelling at high speed and temp still high might be water pump as suggested above or radiator clogged.

Good luck. Hope you can solve your problem soon.

[atl530i]

Flush the system also. If you have a clog or partial block somewhere, your system will run hot.

[attack eagle]

it has to be the fan clutch. as you indicated, it seems to be semifreewheeling when hot.

The problem varies in intensity depending on external airflow over the radiator. Dead givaway right there.

[pushpins]

Does the 520's water pump have the plastic impeller? I would check that as I have heard they tend to "spin" freely when they fail, not allowing water through the system...

It may be on it's way out in your case which is why it will cool down when you drive.

The old one had a plastic impellar. So I dont think its the waterpump. However, I am pretty sure the fan clutch is gone. I think I will start with that, and then flush the system, like one said.

The car is in the workshop getting the transmission fixed. It leaks oil. So I cant really get started on it again before the oil leak is taken care off. But I seriously hope it isn't the head gasket. I'll get back with the outcome.

A picture of the car. Havent done much to it yet. Have big plans with 18" paralells or some BBS wheels. 540 sideskirt and AC-schnitzer front bumper. :D

I dont have necessary permissions, so can someone post the picture?

(h)ttp://img295.imageshack.us/img295/7421/p1010169iw8.jpg

[eightynine535]

also check out the AUX fan. Mine only turned on at high speed, so I changed the resistor which was broken in two. also change the double temperature swith in the radiator.

[pushpins]

Can the temperature swith in the radiator cause the temp gauge (think its gauge) to suddenly pop back and forth? Before the engine overheated, the gauge has been extremely wierd. Jumped around all the time.

And, I think I only have one fan. I dont have AC.

[pushpins]

bumping this one.. still the same problems, havent used the car since..

[bmwpower]

bump for more updated info....thx