E30 Zone

hi everyone

a friend of mine has a 318i m40 and is having problems with overheating. He is acumilating pressure and is having to daily release pressure from his bleed valve on his radiator. It appears that the lower pipe that goes from the rad to the block is stone cold and soft, whereas the top pipe from the rad to block is warm and hard.

He has fitted a new radiator and thermostat and the system was bled properly during instalation.

His usual mechanic said he has a faulty guage, though his incompetence is really annoying me as that would not explain the pressure build up!

Also where are you m40 boys having your temp guage sit once warm, bout halfway or just under?

Any recomendations guys would be much appreciated.

Strange one. I can only suggest checking the thermostat off the car - in a pot of boiling water to see if it opens fully. If that's OK I can only think that maybe a failing head gasket is creating a hot spot which is boiling the coolant and making an airlock. Maybe the block needs backflushing. Can't think of anything else.
Edit: Just had another thought. You don't sound as if you have much confidence in your 'mechanic' I assume he had the heater on full blast whilst refilling the system?

blockage ,heater core ,is it altered by heater temp control?