Little help bleeding the cooling system

[Jay 535i]

Bruno installed a new rad for me and despite his efforts there is still some air in the system. I had to bleed the system twice on the way from Ottawa to Toronto yesterday as air bubbles twice stopped the coolant from flowing and sent the temp needle towards the right.

I'm going to follow the Bentley manual instructions for bleeding the system, which I've done before successfully. I just wonder if anybody has any additional tips for getting all the air out with a minumum of fuss. I know the M30 is known for being a PITA in this respect.

Thanks!

[nuclearfusion]

You can uncap the reservoir and see that there is a flow of coolant from the overflow hoses into the reservoir. If not they may be plugged, require clearing, etc.

Alternately, with engine cold you can open the bleed screw and reservoir top and blow with mouth air into the reservoir top. Thus slightly pressurizing the system and blowing any bubbles out the bleeder.

As well you might want to try removing the brass plug between the two temperature sensors on the thermostat housing and putting some coolant in there when the whole works is cold. The plug in question is #3 in this diagram:

http://www.realoem.com/bmw/showparts...18&hg=11&fg=35

Also a small hole drilled in the top of the thermostat flange before installation makes bleeding the system significantly easier since it can be done when the thermostat is closed (ie: engine cold).

You can also use a "burping" technique by squeezing the coolant hoses in combination with the above.

Those are all the M30 bleeding tricks I know. Hope that helps...

Enjoy!

Fusion