Bleeding cooling system

[johnnyroper]

What an absolute nightmare to bleed cooling system on 1.9tdi engines,changed stat other day ran up engine have drove it and had up to 90 degrees but heater still refuses to bleed.
Had cap off several times to allow air out but still no joy,anyone got any suggestions how to bleed the system?
I don't remember it being this hard after head gasket work,unless the thermostat being dodgy aided air removal by opening early?

[insanitybeard]

I've had to bleed the coolant system a few times after water pump removal, removal of booster heater etc and to be honest, apart from the time taken to warm the engine up (unless you're driving) I've had no issues getting the system including the heaters to bleed, I've tended to leave the front and rear heaters switched full on whilst carrying it out to assist.

If you can't bleed them properly then you could have another issue, is the secondary water pump running properly? Have you checked the return pipe restrictor in the small bore coolant pipes near the expansion tank to make sure it's allowing air bubbles to return to the expansion tank? If the head gasket previously failed there's a chance crud and scale normally deposited (and not causing problems with coolant flow) against the pipes and passageways of the cooling system has been dislodged and is blocking up the heater matrixes for example.

[Chrispb]

Facing uphill or jacked up is better and is the small return hose to the bottle allowing through a small amount of coolant, you can normally see this with the cap removed and engine running?

[johnnyroper]

Sorry I should have said on first post. The cooling system was flushed out,fully drained including boost heater and refilled with fresh. The heater matrix was renewed and the restrictor cleaned out,up until stat change was flowing fine and providing heat just not getting fully up to temp,I also re brushed the run on pump so that works fine.

Will try facing it uphill see if that releases the air lock as I can hear run on pump pushing air around it just won't come out.

[johnnyroper]

Tried jacking up but still air lock persisted boost heater kept over heating due to air locking also. Finally managed to shift it by driving about 10 miles with expansion bottle cap off.
All now good temp sits at steady 90 and warms up quite quick for a pd lump even when boost heater switched off.

[insanitybeard]

The past couple times I've had to drain the coolant on the Galaxy I've refilled it and let it run at idle/ static for 10-15 minutes, then I've gone out for a run armed with a couple of litres of coolant and stopped every couple of miles carefully removing the header tank cap each time until the thermostat opens and the coolant level drops markedly. Most of the air tends to purge in one hit when the thermostat opens with any further air pockets/ bubbles purging overnight once the engine cools down after being taken out for a run.