M20 Cooland Bleeding Issues........Possible Water Pump Issue

[Kedge]

Task for today was to get the M20 bled up and ran in but I'm having major issues bleeding the coolant.

All that keeps happening is that as soon as the engine warms up it starts putting pressure back the the radiator (running an E36 rad) and through the top, regardless as to whether the bleed nipples are open.

Initially I thought it was the thermostat even though I'd tested that in a pan, removed that and the same happens. Checking the pipe from the had to the heater matrix and that is pretty much dry which is now leading to me thinking I've got another duff water pump.

Also of note, I've blocked off the block and thermostat outlets that are for the throttle body, could this be causing an issue?

Cheers
Dave

[daimlerman]

Only three 'pinch points' in the system;
Pump
Radiator
Thermostat

Given that you have tested the 'stat and replaced it the correct way round ,
I would suspect the pump next.May be worth making sure that the radiator is flowing properly,first,though,as that's a free check!

[Kedge]

The stat is still out at the monent, the rad and pump are both brand new as well.

[daimlerman]

Then unless you have a faulty pump,unlikely as you would have made sure the impeller was properly fixed and the thing spun freely before installing,all I can suggest is old fashioned witchcraft!

Raise the front of the car as high as possible,stand on your left leg and insert your right index finger into your left ear.
I must point out that the silly stance has never worked for me,but other's swear by it.

You have the heater set to max,of course?

[Kedge]

Yup, heater on max temp and speed!

[Brianmoooore]

See my last post here: http://www.e30zone.net/modules.php?name ... c&t=252001

[Kedge]

Cheers Brian, will give that a go. I assume that relieves a potential airlock?

[Sanchez]

I want to check my thermostat as the needle never gets to the first white mark, it get close but not close enough.

Does the stat need to come out or can I check somehow?

[Brianmoooore]

The only way you can check a thermostat is to take it out, place it in a saucepan of water with a thermometer, and heat the water while observing what happens, unless, as is common with genuine BMW thermostats, the bridge piece is broken at one end, when you can toss it straight into the bin.

[Sanchez]

Cheers Brian.

[G-Bear]

My m20 gives me problems every time when bleeding it's waterways. Opening up the top hose at the bulkhead (as Brian mentions in that link) on the near side works every time for me. Undo the hose (which from reading above I think you may have done) if it's dry, then open the cap on the reservoir bottle this should release presure and draw the air lock out.

Might not resolve the problem as your symptoms differ to my usual ones but no harm in trying.

[Kedge]

I'm well and truly stumped on this.

Tried the top heater matrix hose off until water came out both ways but still it's pressuring the header tank as soon as it's warm (thermostat is back in). I'm not getting any heat out of the fans but I can now get water through the bleed nipple on the thermostat housing but not the one on the rad (e36 rad fitted).

Just popped off the hose on the back of the head and there's water there.