wrong bleeding procedure or blown head gasket?

[bavareze]

Hello,

I am having a problem with my 323i with 170k.

One week ago it overheated badly. Someone else was driving I noticed the expansion tank was punctured and coolant leaked.

So I got a new tank. After that I filled with coolant. I opened the bleeding screw while filling to make sure air goes out. Then when I start the car I see some issues:

- immediately a lot of pressure builds in the hoses.
- coolant does not circulate through the hoses

so I went to get a new thermostat, put it in, redid bleeding.

same issues: as soon as I start the car there will be a lot of pressure in the cooling system.

shall I go ahead and assume head gasket is gone?

Thanks!

[brettski]

If you leave the cap off the expansion tank does the system still build up pressure?
Try running the car without a thermostat installed at all, maybe there is an air lock stopping it from working.
Check that the hose that runs from the radiator to the bleeding screw and expansion tank isn't kinked, apparently that can stop air from being purged.

[bavareze]

Originally Posted by brettski

If you leave the cap off the expansion tank does the system still build up pressure?
Try running the car without a thermostat installed at all, maybe there is an air lock stopping it from working.
Check that the hose that runs from the radiator to the bleeding screw and expansion tank isn't kinked, apparently that can stop air from being purged.

even without thermostat (which, btw, comes with the housing so it's not possible to remove on E46) the car shouldn't build pressure in 10 seconds after starting. should only build pressure after water is boiling inside.

The hose from radiator to bleeding screw is 4 cm thick, not blocked at all.