Coolant Bleeding Procedure

[angusbn]

New BMW blue coolant, hoses, water pump and tstat.

Engine still runs very hot and the check engine light comes on after 10-15 mins driving.

I've tried to bleed the system a few times with no luck.

What's the fool-proof method to bleed the system?

Note that I have by-passed the heater core but I doubt that's the problem. No visable leaks anywhere.

Thanks.

[philbyil]

Is this an M50 motor???

If it is, it's simply bleed, bleed and bleed again :(
Make sure you have coolant up to the Kalt level in your reservoir.
Raise your car up on ramps to get the rad bleed screw as the high point.
Set your heater on hot and run the fan, start car and get warmed up properly.
Then open bleed screw a touch and allow coolant to bubble out. When bubbling stops, tighten bleed screw and check coolant level in overflow...top up if necessary.

Take car out for a run around the block with heater full on, then allow engine to cool, then do it all again. Checking for bubbles from bleed screw.





New BMW blue coolant, hoses, water pump and tstat.

Engine still runs very hot and the check engine light comes on after 10-15 mins driving.

I've tried to bleed the system a few times with no luck.

What's the fool-proof method to bleed the system?

Note that I have by-passed the heater core but I doubt that's the problem. No visable leaks anywhere.

Thanks.

[angusbn]

M30 engine.

[uscharalph]

Is this an M50 motor???

If it is, it's simply bleed, bleed and bleed again :(
Make sure you have coolant up to the Kalt level in your reservoir.
Raise your car up on ramps to get the rad bleed screw as the high point.
Set your heater on hot and run the fan, start car and get warmed up properly.
Then open bleed screw a touch and allow coolant to bubble out. When bubbling stops, tighten bleed screw and check coolant level in overflow...top up if necessary.

Take car out for a run around the block with heater full on, then allow engine to cool, then do it all again. Checking for bubbles from bleed screw.

Heater won't help as his heater core is bypassed.

[Rus]

The way I've always bled my M30 is as follows:
1) Top off coolant on cold engine while squeezing the top radiator hose to force air bubbles out.
2) Start the car with reservoir cap on and use the bleed screw on the thermostat housing to remove air. If equipped, use the heater core feed hose air bleed as well.
3) Verify that the radiator hose become warm.
4) Drive the car and repeat the bleeding to remove all the air.

From your description it sounds as if the radiator is blocked or not receiving the hot coolant. Be sure you verify this using the hoses.