airlock trouble 325i

[trigger]

as above , cant seem to get the air out of the cooling system, top hose is still not staying full of water!

ive bled it from the thermostat housing and tried bleeding with the front end jacked right up and ive even tried the 2ltr coke bottle trick, and even pulled off the return for the heater matrix.
the heater top vents were blowing hot for 30mins or so but not now, so i would imagine it's air locked again!

I NEED A GOOD TRICK please anyone , has anyone modded the coolling system ?

[jcjdavis1]

Hi. Have you tried this one.-

Engine running
Heater controls set to hot
Header cap off
Keep squeezing all water pipes watching for air bubbles
Top up coolant as required
When satisfied no air put header cap back on
Release bleed valve on thermostat housing and check that no air and only coolant is coming out .

[DORAS]

heater matrix could be clogged up. I had one like that it was bled o.k but now heater. try taking the pipes off any shuve a hose pipe in one and see if it comes out the other. if not poor some descaling acid in, let it soak and wash it out.

[trigger]

Hi. Have you tried this one.-

Engine running
Heater controls set to hot
Header cap off
Keep squeezing all water pipes watching for air bubbles
Top up coolant as required
When satisfied no air put header cap back on
Release bleed valve on thermostat housing and check that no air and only coolant is coming out .

yes, for over two hours !

[trigger]

heater matrix could be clogged up. I had one like that it was bled o.k but now heater. try taking the pipes off any shuve a hose pipe in one and see if it comes out the other. if not poor some descaling acid in, let it soak and wash it out.

i will try flushing it first, but if it doesnt work how do you get the descaler to stay in the matrix or do you just add it to the system?

[DORAS]

no take both pipes off, block one, poor it in and wait. it wont fill completly but there will be enough in it to clear a pathway that will allow the water to circulate. dont leave it in too long 15mins max. try the hose pipe first though.

[Brianmoooore]

Don't understand what you mean, "top hose is not staying full of water". If it has air in it, then you haven't bled all the air out. Once it's bled, it's bled. It doesn't unbleed itself! If you have bled it all out, and air still gets in there, then the head gasket has blown or the head cracked.
If you flush the heater matrix with a hose, it's essential that you connect the hose to the bottom stub pipe on the bulkhead, or you will damage the heater valve.

[trigger]

just replaced the head gasket and all other associated parts due to finding mayo under oil filler cap and oily mayo mush in the expansion tank also that the water level kept going down but since doing the head gasket none has reocured, it didnt show any signs of overheating either!
water level is still remaining the same but still pushes up slightly when been running for a few minutes with cap off, like theres still air in the system and top hose still feels spongy like its full of air.

also the flowpipe from back of head to heater matrix feels very hard but the return pipe (top one) doesnt.

[Brianmoooore]

Was the head refaced? How much corrosion was there on the waterways that come close to the gasket fire rings?
If the air is out, it's out! The only thing that can replace the coolant then is gas under pressure from the cylinders leaking into the coolant.
Only other possibility is that the system isn't pressurising, and is blowing out the coolant due to local boiling in the head.