Has anyone got a definitive guide to bleeding the cooling system for a M52 (E36 aircin rad) in a E30? I've searched all over and seem to find conflicting advice.
Please help!
Bleeding cooling system - please help!
Moderator: martauto
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e30-EVN
- Old Skooler
- Posts: 3382
- Joined: Sun Dec 13, 2009 11:00 pm
- Location: S.Wales
pressure bleed it with the bleed screw on the rad open....... this is the best way for me and i can bleed these now in like 15 mins and first time 
start by filling the matrix through one of the pipes, this makes it easier that end, once done reconnect the matrix stub then with the bleed open, pour a ltr of coolant in through the rad, then blow it through, pour another ltr in and repeat this procedure until pure coolant escapes the bleed opening. when this happens blow so that coolant escapes and keep blowing while you tighten the screw, you have to keep blowing while you tighten so that it doesnt suck any air in when you run out of puf!
and usually everytime for me, thats job done mate.
start the engine and let her get to operating temp then crack the bleed screw to make sure any little trapped air pockets escape
start by filling the matrix through one of the pipes, this makes it easier that end, once done reconnect the matrix stub then with the bleed open, pour a ltr of coolant in through the rad, then blow it through, pour another ltr in and repeat this procedure until pure coolant escapes the bleed opening. when this happens blow so that coolant escapes and keep blowing while you tighten the screw, you have to keep blowing while you tighten so that it doesnt suck any air in when you run out of puf!
and usually everytime for me, thats job done mate.
start the engine and let her get to operating temp then crack the bleed screw to make sure any little trapped air pockets escape
A 2 door e30 with 8 cylinders, what could be better 
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dani_d
- E30 Zone Newbie
- Posts: 14
- Joined: Wed Aug 31, 2011 11:00 pm
^^^
Thanks.
So, to confirm:
Engine off - fill with coolant as described above & blow into integrated expansion tank until water comes out of the bleed screw.
Which position should all the heater controls be?
Should the engine be started with the rad cap off or on? Presume from the description above that it should be on to allow the system to get up to pressure before opening the bleed screw to allow any final air to escape?
Thanks again, don't want to fry this engine!
Thanks.
So, to confirm:
Engine off - fill with coolant as described above & blow into integrated expansion tank until water comes out of the bleed screw.
Which position should all the heater controls be?
Should the engine be started with the rad cap off or on? Presume from the description above that it should be on to allow the system to get up to pressure before opening the bleed screw to allow any final air to escape?
Thanks again, don't want to fry this engine!
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e30-EVN
- Old Skooler
- Posts: 3382
- Joined: Sun Dec 13, 2009 11:00 pm
- Location: S.Wales
Yes, fill using my procedure with the engine off and heater set to hot position so that the heater valve is open.
Once pure coolant comes from the bleed close it while blowing!
Then replace the rad cap and start the car to let it build up to operating temp..... With the engine running I set the heaters to hot and full on!
I was worried at first but if your electric fan is working as it should it will cut in at 88 degrees and won't overheat.
This method is fool proof and last time I swapped my m50 for the 52 I bled mine in a matter of 15 mins. That was a good few months ago and she's still running great
Another thing I want to make clear is make sure your antifreeze to water mixture is around 60 percent antifreeze to 40 percent water!
If these are run on only water or a weak mix of antifreeze the water ports in the head gasket will rust up and cause issues later on
Once pure coolant comes from the bleed close it while blowing!
Then replace the rad cap and start the car to let it build up to operating temp..... With the engine running I set the heaters to hot and full on!
I was worried at first but if your electric fan is working as it should it will cut in at 88 degrees and won't overheat.
This method is fool proof and last time I swapped my m50 for the 52 I bled mine in a matter of 15 mins. That was a good few months ago and she's still running great
Another thing I want to make clear is make sure your antifreeze to water mixture is around 60 percent antifreeze to 40 percent water!
If these are run on only water or a weak mix of antifreeze the water ports in the head gasket will rust up and cause issues later on
A 2 door e30 with 8 cylinders, what could be better