How to bleed coolant on Mini Cooper (non-S)

[flatland69]

Hi guys, there seems to be an airlock in my coolant system after having a new radiator fitted, and simply unscrewing the bleeder screw doesn't want to get rid of it. I was wondering what would be the correct procedure for bleeding? I phoned 3 BMW dealers, and each one gave a different way of doing it...

[SteveM3]

Wait until coolant comes out of the bleed valve/vent screw and tighten it. Set your heater
controls to maximum temperature with fan on low and start the engine. Top up coolant
as car idles. If that doesn't work have a word with the people who fitted the radiator as
they should have done all this for you.

[zoooooom]

There are two bleed screws, the one at the front is easy to see and there is another to the left of the battery (almost under the battery).

Also be sure to fill it from the filer cap and not the expansion tank.

[richg40]

there is actually 3 bleed screws.

[flatland69]

We found one next to the inlet manifold, and one at the back running towards the heater. Where is the third?

[richg40]

One above the alternator, one behind the battery box one the pipe to the heatre matrix. the third is an 8mm bolt down by the throttle body towards the head which can be difficult to see.

[oldmots]

Quote: Originally Posted by flatland69 (original)

Hi guys, there seems to be an airlock in my coolant system after having a new radiator fitted, and simply unscrewing the bleeder screw doesn't want to get rid of it. I was wondering what would be the correct procedure for bleeding? I phoned 3 BMW dealers, and each one gave a different way of doing it...

There are three bleeds as has been said. Open each bleed and add coolant until bubble free coolant emerges. Durign this process, turn the ignition on and turn the heater to full heat and full blower and leave it on. Close each bleed, remove the system pressure cap and start the engine, lettign it run until bubblres stop coming up in the filler neck. this will take untl the thermostat opens and the upper radiator hose gets and stays hot. then close the cap and you are done. Be sure to do this carefully, an airlock can give you a blown headgasket in a heartbeat.

[Randall Raines]

Quote: Originally Posted by richg40 (original)

One above the alternator, one behind the battery box one the pipe to the heatre matrix. the third is an 8mm bolt down by the throttle body towards the head which can be difficult to see.

Watch out for dropping the little 8mm one (I learnt my lesson a long time ago ), plus if it does come out totally it can be hard to get back in (sometimes ) .

Most readers after reading this just completely ignore it! Every body seems to agree that there's 3 bleed screws, Is there actually a 4 th on some models?, I'm only saying this, and I don't want to start any confusion , because I removed a cylinder-head off a damaged engine and then I noticed a bleed screw (allen screw, which could only be a bleed screw , on the cylinder-head) on it which I have never noticed before on other engines that I have worked on before, I don't know what the engine was out of, only that it was a 1st Gen petrol engine, after I noticed the screw I compared it with other engines & cylinder-heads that I had at the time and that I have had since and I have never found one since (I haven't done many of the last of the 1st Gen though), I couldn't even tell you where abouts the screw would be as the head was scrapped and I can't actual remember where abouts it was , just that it was there somewhere (I just assumed that it was a modification to aid bleeding because of the usual water noise that people hear in the heater matrix ).

It's not important, I'm just curious! .