Nice and fast way to bleed coolant in M20

[intuitivejohn]

Comparing the 2 Bleed Methods Here...Standard Vs. "Forced" BMW actually
shows both.

I ran across the bleed instructions from BMW inside their deep dive, "We're the
gnomes in the secret mountain" for the Mechanics who work on these things..
and they show both ways.

They have a "Standard Bleed"

And they have a "Super Bleed" where they hook it up to a vacuum contraption
that eliminates any and all air...It doesn't look that complicated as far as a
piece of equipment. Just BMW Retail + expensive.

Hooray for the $6.00 PumP!!!

[ForcedFirebird]

Wow old thread!

I have no issues bleeding the m20 systems, and I do a LOT of them, pretty much on a daily basis. It's real simple physics, the coolant needs to be poured in higher than the uppermost hoses/passages (fluids always seek level). So, I use a $1.50 yellow radiator funnel from the local parts store - it fits perfectly in the expansion tank fill hole. Fill it up to the top of the funnel and just wait a minute and all the bubbles will come up through the 8mm hose off the top of the radiator. As the bubbles come up, keep the coolant to the top of the funnel and after a few minutes it will fill completely. Been doing it this way at the shop for the last 11yrs, have never had an air bubble issue - and in fact don't even open the bleeder screw half the time (if I do, it just makes the process only slightly faster).

When at the track and need to bleed the system without a funnel, I just simply detach the expansion tank and hold it up higher than the hood. Does the same job as the funnel.

Link to said funnel...

https://shop.advanceautoparts.com/p/...0703/9010042-p

If you want to spring a few extra bucks, there's one with a stopper in it so you don't spill any coolant once it's topped off...

https://www.amazon.com/WirthCo-32027.../dp/B007RXBSVS

[digger]

i did another one a couple weeks ago. front was on ramps had zero issues, no holes in t-stat

[Poorhouse]

Wow old thread!

I have no issues bleeding the m20 systems, and I do a LOT of them, pretty much on a daily basis. It's real simple physics, the coolant needs to be poured in higher than the uppermost hoses/passages (fluids always seek level). So, I use a $1.50 yellow radiator funnel from the local parts store - it fits perfectly in the expansion tank fill hole. Fill it up to the top of the funnel and just wait a minute and all the bubbles will come up through the 8mm hose off the top of the radiator. As the bubbles come up, keep the coolant to the top of the funnel and after a few minutes it will fill completely. Been doing it this way at the shop for the last 11yrs, have never had an air bubble issue - and in fact don't even open the bleeder screw half the time (if I do, it just makes the process only slightly faster).

This X2.

I had a lot of trouble getting mine bled with the ramp method. Doesn't seem like it would ever work as the bleeder isn't the high point, even on ramps.

Found mention of the funnel method. Made sense as you are elevating the bleed point. I bought a fancy Lisle funnel on Amazon for $12. Worked perfectly in just a few minutes.

[Xelo]

Do you guys do this with the engine running ? I asume yes, otherwise there will be air on behalf the thermostat not opening ?
And also, what do you do with the remaining coolant in the funnel as the system becomes full ? How do you take the funnel out without spilling ?

[ForcedFirebird]

Do you guys do this with the engine running ? I asume yes, otherwise there will be air on behalf the thermostat not opening ?
And also, what do you do with the remaining coolant in the funnel as the system becomes full ? How do you take the funnel out without spilling ?

Link in post 17 has a stopper in it. I don't use one like that, so coolant goes first, then water, spillage doesn't much matter. The funnel causes the level to be higher than anywhere other point, so both sides of the thermostat get filled. Sometimes you will get a bubble in the heater core that will show after running and heater turned on, but generally not enough to get to the bottom of the expansion tank - easily topped up.