Bleeding the E34 Cooling system

[vping]

How are the cooling systems to bleed? I heard that it is a pain in the ass.

[genphreak]

Not at all. If the system pressurises, you'll be ok. If it doesn't you have no hope.

Depends on the model- M20 and M30 you have to bleed manually. All the later engines autobleed, so long as you follow the correct procedure. Most importantly you have to use the factory coolant, or Prestone, or a very few special others. Using any other 'compatible' coolant will end Burn Your Wallet later....

[shogun]

m30 bleeding page_2

[ScottyWM]

Vince, I must have bleed my M50TU a dozen times over the years given all the water pumps and radiators I've replaced (yes I used BMW coolant). Never had a lick of trouble bleeding. Park it with the nose pointing uphill, follow the procedure, no muss no fuss...

[vping]

Thanks guys.

My daughter blew a heater hose and had to get it taken to a local shop. $300 for the hose. Wanted to then charge me another $400 for the other hoses and the thermostat. I'll fess up and say I should have replaced all the hoses when I got it but I assumed the prior owner did because he kept such great care. Live and learn. I'll take care of the other hoses and thermo myself when she comes home.

Something good came out of it though. I might have found another. A1997 528i. I'll hear more about it in a few hours and will let ya know.

Cheers,
Vince

[John in CT]

300 bucks, now that's a New York price alright,

Sheeesh,

John

[vping]

Hey Scotty,

When you have a moment, contact me via email.

vping at optonline dot net

[Victor]

Scotty,

I wonder if you'd mind clarifying a points regarding bleeding air from the M50TU please. What do you mean by "if the system pressurizes?" Also, the "procedure" involves filling the expansion tank until coolant overflows from the bleeder. But after that drops, there may still be trapped air, so I'm bleeding again and again after drives without the full expansion tank and getting bubbles. What's going on here ...

Thanks,
Vic

[Rustam]

I bleed it simply (m30 engine) :

1- let the engine work, it will heat beyond the middle notch. I let the needle touch the red.
2 - stop the engine and turn the bleed screw. Some coolant will come out and steam.
3 - let the engine cool
4 - check level and refill
5 - repeat the cycle till overheating stops.

By third cycle the system is usually blead. Simple and effective.

[Victor]

Wow. I'd be reluctant to see my (M50TU) engine get that hot. I've never seen it past the halfway point. And especially if there are air pockets, I'd fear warping the head.

Bentley's procedure is characteristically scant, leaving much to the imagination...