M20 oil breather tube

[JimmyMc]

Hi all,
Been sorting out a leak on another thread.
Wanted to clear up whether people have used a washer at the top of the tube, as well as the bottom. Realoem lists 2, but there wasn’t one there when I took it off.
Thanks.

[JimmyMc]

I’ve seen 2 versions of the story.
1. O-ring at the top, then spring, washer, o-ring on the bottom.
2. O-ring at the top, then washer, spring, washer, o-ring.
What has everyone done that worked?

[reggid]

i wouldnt do washer at the top (even though i thinks how BMW did it) it seems to not allow the o-ring to seat fully

[JimmyMc]

i wouldnt do washer at the top (even though i thinks how BMW did it) it seems to not allow the o-ring to seat fully

I think that’s what I’ll go with. Thanks.

[reggid]

i wouldnt do washer at the top (even though i thinks how BMW did it) it seems to not allow the o-ring to seat fully

I think that’s what I’ll go with. Thanks.

just do a mockup the tube and o-ring into the manifold to see. these days im running a different manifold so recollection regarding the stock one is shady

make sure you lube the o-ring with oil or suitable grease otherwise it may tear

[JimmyMc]

Seems to be another problem. When inserting the tube with the IM attached, the bottom of the tube doesn’t engage with the block when the top is fully engaged.
Does anyone happen to have any tube dimensions? I think it’s been, cut but not sure. I assume this was part of the original bodge.

[reggid]

yeah should be like 48mm. someones lopped off 10mm

[twright]

I'll bet someone cut 10 mm off of it to try and make it so that you could take that tube off without taking off the intake manifold.

Did shortening it work?

[paultv]

How important is it that this tube is airtight to the manifold and sump area? Surely it has to be leak free to avoid idle running issues in the same way as the dipstick and oil filler cap/ breather hose.

Correct ?

Paul

[reggid]

How important is it that this tube is airtight to the manifold and sump area? Surely it has to be leak free to avoid idle running issues in the same way as the dipstick and oil filler cap/ breather hose.

Correct ?

Paul

it is a "vacuum leak / unmetered air" if you have the valve cover venting back to throttle body like the factory.

If you plug throttle nipple and vent valve cover to atmosphere it doesnt matter as it is nolonger a vacuum leak/unmetered air

[JimmyMc]

I'll bet someone cut 10 mm off of it to try and make it so that you could take that tube off without taking off the intake manifold.

Did shortening it work?

Yes, I was ultimately able to get it in and out with the IM on, which was an alarm bell. They’d filled the gap with sealant held in by a ball joint boot! I’ve ordered a new one, as I’m sure this is where my air leak was.

[JimmyMc]

yeah should be like 48mm. someones lopped off 10mm

Thanks for confirming. Useful to the info recorded.
I’ve ordered a new one.

[BristolE30]

I’ve never seen this before on my oil breather tube? Isn’t it just hose clamped on??

[Cloggy Saint]

Can't use a hose clamp on this as both ends are 'male'.

[JimmyMc]

yeah should be like 48mm. someones lopped off 10mm

I can confirm 48mm from the bottom of the lower lip is correct. New part has arrived.

[HJ1981]

As i pulled mine out, i only found one washer, and it was sitting above the O-ring.

Basically spring, washer then O-ring. I did order two of those o-rings and it looked strange and never got the o-ring to seat in properly, so i just used one.

[BristolE30]

Can't use a hose clamp on this as both ends are 'male'.

Mine is just hose clamped on unless we are talking about different parts. Tube that goes from the valve cover to the intake manifold?

[JimmyMc]

Can't use a hose clamp on this as both ends are 'male'.

Mine is just hose clamped on unless we are talking about different parts. Tube that goes from the valve cover to the intake manifold?

Different part I think. The tube runs from the underside of the intake manifold to the engine block. It’s made of metal with an o-ring either end.