M52 coolant bleeding issue

[Leon.stt]

Guys,

I have a problem trying to bleed my coolant system.
I flushed my cooling system today using compressed air and tried to get as much old coolant as possible out of the system. Everything went pretty well until I tried to bleed the system. My car is a 1990 E30 sedan with M52B28 swapped. The cooling system is using a remote expansion tank, located where the battery used to be (on the passenger side fire wall).

What I did to bleed the system is by filling the expansion tank to the brim and wait until the system sucks all the liquid. I left the cap off. However, after 5 min or so, I didn't see the coolant level drop and my temp gauge was hovering around 3/4. So i switched the engine off, then all the coolant was sucked in to the system.

Then i topped it back up and restart the engine and waited. Basically same procedure as before. But this time I notice that my coolant in the expansion tank was boiling like crazy and started to overflow. At this point my gauge was showing 3/4 again. So I swtched my engine off, again the coolant got sucked in. I didn't see any leaks anywhere. I let my car cool down.

Then, As I started the engine for the third time, the idle was pretty rough. Like its misfiring. But there was no smoke coming out of the exhaust. So I drove my car into the garage and immediately switched the engine off. At this stage, all my coolant in the tank was gone. All in the system. So I need to get more coolant and for the time being I'm not planning to start my car

I'm at lost right now. Anyone has the same experience as me? Mind sharing your thoughts as what cause my engine to misfire? Does air in the cooling system cause the engine to misfire?

[bmwdirtracer]

At the top of this forum you will find an instructional thread for items like this.

https://www.bimmerforums.com/forum/s...6#post23416186

Personally, I use a vacuum-fill system, and never have to deal with bleeding anymore. If you have a compressor, the rest is fairly inexpensive.