E30 coolant bleeding causing greif

[pureboiracer 0]

Hey guys, trying to bleed race car coolant. Car is a series car, no heater core, new thermo, wp etc when rebuilt, rebuilt motor, done no ks. Have done the normal bleeding process, on a slope, bleed scew, squeeze house etc. have left overnight full of water and it still wont bleed, it just boils over. Any tricks or points of advice? Have blead pleanty of times before on other cars but never been this anoying.

Cheers oli

[hotwire 352]

Pretty well covered options Olli.

I usually only two thirds fill the system & run until thermostat opens to allow air to escape before topping up.

How are the heater hoses bypassed - a chance for trapping air?

[pureboiracer 0]

It is bypassed by a single hose running from back of head to thermo housing. no joins so i dont think it can trap air.

The thermostat opens a few min before it boils over, perhaps it is not cooling enough, causing boiling. I dont think the viscouse fan is too flash so will wire up the electric tomorrow.

[hotwire 352]

Cant imagine it overheating that much in this present weather - particually if it is stationary when doing it?

Sounds like an airlock to me. They can be a bitch to bleed:-

[pureboiracer 0]

Yeah i know they are a bitch but this one is testing me... i have removed the top radiator hose, replaced it with 2 other hoses sticking way up in the air, filled them both with water and left it over night, might have another crack tomorrow.

[sp8s 1]

Read somewhere that a 2mm hole drilled into the top of the thermostat aids bleeding the system.

[BM WORLD 1265]

also have had faulty new thermostats before . or lazy ones , test it in a cup of boiling water.

yes and drilling a samll hole helps to let the air behind them out .

also could be sleigtly blown head gasget/cracked head ,pressureising the coolant system

[pureboiracer 0]

have tested and drilled the thermo. i hope its not the head gasket, any way to tell? no oil in water etc, no steam in exhaust,no sign of water in cylinders..

[Jono51 58]

have tested and drilled the thermo. i hope its not the head gasket, any way to tell? no oil in water etc, no steam in exhaust,no sign of water in cylinders..

Oli, have you run this engine before, hasn't it been rebuilt?

[BM WORLD 1265]

have tested and drilled the thermo. i hope its not the head gasket, any way to tell? no oil in water etc, no steam in exhaust,no sign of water in cylinders..

get a TK test done.

. also force water in main rad hose with rag around it with bleed nipple open untill only water comes out.

[pureboiracer 0]

Yes, its been rebuilt.

Today I did the following:

Topped up water, pressurised system with regulated composed air wile squeezing hoses etc.

Compression tested cylinders, all were 190psi after 10s if cranking.

Blead up cooling stem with motor running, drove up the st a few times, temp got to just above half.

Packed up went home.

[pureboiracer 0]

Just had another play, seem to have sorted it now.