leaking coolant?

[///M42 sport]

Cant tell where this is leaking from? its pooling under the oil filter canister. Seems like coolant not sure if there is oil mixed in there as well : /

[Quadrajet]

That's kinda close to where the coolant tube resides. The one that's part of the mess under the hood family.

[///M42 sport]

I guess it could be from that plastic tube that attaches to the block

[bmwman91]

Yeah, the black water pipe is a known issue with these engines. It has a tendency to get old and crack. If you aren't sure how old it is, then you should consider replacing it before it does what is often does...break open suddenly. Spend the extra fre $ on the Genuine BMW one, do NOT get the less expensive off-brand one. The cheaper ones don't fit well and are prone to early failure.

I assume that you got a rag in there and made sure that it is coolant. If not, it could also be oil. Sometimes you get a slow leak around the oil pressure sender and maybe that is dripping?

[TobyB]

Well, yeah, change the plastic pipe nonetheless.

But water also goes through the chain case near there, and I seem to remember that even
the water pump can leak out through a designed- in channel (when it fails)
If it's leaking on the other side too, that's a classic water pump.

t

[///M42 sport]

I changed that pipe about 7years ago with a oem part. Might be the seal. Just a PITA to service right now when its 5degrees out.

[bmwman91]

Well, yeah, change the plastic pipe nonetheless.

But water also goes through the chain case near there, and I seem to remember that even
the water pump can leak out through a designed- in channel (when it fails)
If it's leaking on the other side too, that's a classic water pump.

t

Got any other info on this water pump "bypass"? I have heard mention of it in the past, and now that I am slowly and mysteriously losing coolant I wonder if that is related.

[kwill22]

Interested in that also. The only thing I've ever seen there is oil if it's leaking from the sensor

[TobyB]

When you pull the front cover, there are a couple of channels cast into it so that if water
starts leaking, it'll vent to the outside of the car, rather than try to leak into the inside
(oily) part of the motor.

It's been long enough since I had mine off, though, that I can't remember WHERE they went.
I do remember looking at them and thinking "What the waffles?" and then looking at how
the water pump fits in there... it's just a groove in the aluminum part, doesn't look like
much.

t

[///M42 sport]

interesting

I wonder why bmw didnt make that pipe out of metal?

[TobyB]

Boy howdy. Saving a dollar 42 there is just such bad economy.

But then, it also ensured your M42 would expire eventually.

t