M10 Coolant replacement

[nath 131]

Hi Guys

Now that I've been told there is nothing wrong with my steering and after getting all new tyres, I've moved to the next task.

Ive finally gotten around to replacing my radiator, and have a problem.

Upon refilling the coolant and taking reasonable steps to help the system bleed itself (running to temp with cap off etc) the heater has decided not to work anymore, and the radiator top tank (no expansion tank on these) started to bulge as the temp needle went past half way on a drive.

Symptoms that could mean something to someone:

• Coolant level is seen to drop as the car is revved, when looking with radiator cap removed.
• Hose coming from block to heater is warm, return hose is less warm, not cold though.
• All hoses when squeezed seem to be full of water.

-Could the fluid drop indicate lack of NPSH and thus major trapped air that is having a vacuum applied to it as the revs are increased?

-Is my heater just stuffed to add insult to injury? (the valve tests 12V on full closed cold, ~0V at heated temperatures)

-Air expands at a greater rate than water. This may explain my pressure probmlem, but not the fact that the radiator isnt releasing it.

Any help appreciated, I have flushed and changed countless cars' cooling systems before, never had this problem.

Edited June 19, 2012 by nath

[AN E30 Fan 1]

Interested to find out what happens, have to do this later today.

[Etwenty1 45]

so you got the radiator ok then?

The HG has just gone on mine..........

[nath 131]

Removed faulty heater valve, drilled out rivets, took valve apart, cleaned it all up etc etc(long process) back together refitted and heater now works fine. Didnt do much else special to bleed the coolant but seems fine now. Must have been an air lock or some such from the stuck heater.

Car is finally up to scratch.

Chris: Yep put that radiator in cheers. Unsure if it has enough flow actually, but all good.