Help me find where this coolant leak has started.

[alB5]

So after driving around a little i get a small drip coming from the rear of my motor almost off my transmission. When inspecting the motor i found two small pockets of coolant in the spaces highlighted below



Yellow highlighted area:


Red highlighted area:
#1

#2



I recently put in new coolant, but it wasn't purged before. So I added more recently and correctly purged all bubbles from the system. It also idles correctly, and temperature stays in the middle for the most part.


Thanks in advanced.

[Jaxx_]

head gasket.


but seriously, throttle body coolant lines? how do they look?

edit: also heater core hoses are sort of near there, but not really.

[Nairb]

Have you replaced the "mess under the intake?" One of the best preventive maintenance mods you can do on these engines.

If not, GOOD chances that you are having coolant leaks stemming from either your throttle body heater hose AND/OR your "plastic coolant pipe from block." They have a tendency to basically dissolve over time. When I removed mine, it had no "thread" left on it, it basically made a seal with the o-ring and dissolved plastic.. not good.

See this thread: http://www.m42club.com/forums/showthread.php?t=2742 for more information than you will ever need about this and similar problems.

(The plastic pipe with the green coolant in it.)

[alB5]

Thanks for the responses fellas, I had some fun and tore into the intake(s) and took some pics. Tell me what you see.








And one more of the little puddle accumulating under my intake

[vpilarrt]

Can't really see well enough yet because there are still vacuum hoses covering the plastic water pipe shown in Nairb's post but I would supsect its that and/or the 3 water hoses that connect to it or the o-ring where it connects to the engine..

[rjcaptsean]

Dollars to donuts it's the plastic pipe there on the side of the block. They usually crack at the lip where it goes into the block.

It is part number 1 in this diagram.
http://www.realoem.com/bmw/showparts...60&hg=11&fg=10

[twistednut]

Dollars to donuts it's the plastic pipe there on the side of the block. They usually crack at the lip where it goes into the block.

It is part number 1 in this diagram.
http://www.realoem.com/bmw/showparts...60&hg=11&fg=10

I concur. Don't waste your money on a cheaper brand. Buy one from the dealer or Blunt.

[alB5]

Yup, I ordered all the extra hoses from pelican parts. They are all oem (their prices really show that) $45 for three hoses that are cracked under there

Parts are coming by the end of this week, can't wait to get her back on the road! :up:

[alB5]

Here's a few more photos, when removing the coolant hose from that pipe, there was a ridiculous amount of coolant that spilled all over. i had to plug it with a napkin (see pic lol) and I felt around the plastic pipe and felt no cracks or liquid under whatsoever. I might've messed up when reassembling the throttle body coolant system a while ago (haven't driven it much lately) but under further inspection the hoses that connect to the various hoses (coolant and air hoses from valve cover and ICV) have various cracks around the openings so this disassembly wasn't totally useless. Thanks









Thanks to everyone, if there is something I missed, please correct me.

[immajackuup]

most likely your pipe is crack,buy only oem parts because aftermarket doesn't fit well and crack easy.

while you're there do bypass throttle body. use 5/8 heater hose only.

[Reap3r]

You can get rid of majority of those hoses under the intake. My car doesn't have a heater connected & the plastic pipe broke mid fitting my engine so changed to a custom made aluminum one off my mates race car. You can bring it down to one hose going from the side of the block & the 2 on the front (all 3 rad hoses).

Just be careful with the plastic piping. It is very brittle after getting hot so many times. Very easy to break a piece off it.