M42 coolant leak - 91 318i

[Brewerkz]

I have a 318i with 125,000 miles. I have a small coolant leak coming from around the front right (drivers side) of the engine block - dripping on the A/C compressor.

Suspecting this might be the profile gasket, but read it should have failed a long time ago.

Is there a way to confirm or rule out this diagnosis?

[14''BBS]

Profile gasket leaks coolant internally. As in, it mixes with oil. That area would usually leak OIL from the Timing cover, however since you say coolant i would suspect headgasket.

[roguetoaster]

Please clarify your OP, if leaking from the DS it shouldn't hit the AC compressor.

Are you sure it's not coming from under the intake? The plastic pipe is a known failure point.

[Brewerkz]

Leak

Definitely leaking coolant at the front passenger side near the AC compressor. I did the mess under the intake last summer and replaced the plastic manifold.

is there a way to confirm the head gasket?


The head gasket and profile gasket are the same work scope so may proceed with both.

[14''BBS]

A few steps i follow if suspecting a bad hg is if my coolant levels are decreasing and my oil is increasing, then hg leak. Drain the oil, if it resembles chocolate milk, then hg leak, if under acceleration or idle and you have noticably white smoke coming from the exhaust then hg leak. Open your rad cap and start the engine, if coolant shoots out of it, then....

Just a few thoughts or google bad heasgasket symtoms?

[Brewerkz]

follow up

thanks for the insight....oil seems a little thick, no bubbles in coolant, no smoke during idle, but smoke when engine is rev'd.

I am proceeding with the head gasket replacement.

[grke36m3]

could it be the water pump gasket? i didnt think the headgasket could make a external leak.

[Ocell]

Water pump would be a much faster/cheaper fix to try before doing head gasket. I had a failing water pump and the front of my block was a mess. I think it was a slow leak for a long time before it failed hard enough to take my car off the road and make it obvious what the problem was.

[Merlin8]

Could be the coolant hose connector. Damn thing is plastic

[grke36m3]

How difficult is it to remove the pump? Any tricks if its ceased?

Sent from my SAMSUNG-SM-G925A using Tapatalk

[Ocell]

There are 4 bolts that actually hold the pump in. The pump has two other holes that are threaded in the pump and don't have bolts in them. You take the 4 bolts out, then put two back into the threaded holes and tighten them down. They thread through the water pump and press against the block, sliding the pump out as you alternate between threading the two bolts in. (You want to do it evenly.) It's a pretty clever setup.

For getting a new pump in, you'll want to use some silicone lube on the o-ring. I tried sliding mine in with just coolant as lube, but there was no way that was happening.

[Ocell]

Here's a write-up with great pictures.

http://www.m42club.com/forum/index.php?PHPSESSID=5rmspkfl3bkbdqo0h2i9pl4gt0&topic=9162.msg76563#msg76563

[romeomike]

Had the original head gasket fail in the OP's location at the 50K mile point in 2000. Was philosophical about it then, since the profile gasket was changed at the same time.

Second head gasket failure was tied to a 2014 intake valve job to go with replacing all eight exhaust valves. The VR head gasket was just a bit off around one of the coolant passages, enough to make it leak down the driver's side of the head. Since the repair was under warranty, the garage did a replacement at no additional cost to me. So keep that in mind if you're going to pull the head.

[TobyB]

...the water pump's designed to leak out of a small passage on the exhaust side of
the engine if the seal fails...

what I found,
t

[CharlaybitM3]

Bumping for clarification...

Yesterday my '91 318 started leaking coolant pretty heavily. It's coming from the front of the motor somewhere. At first I thought water pump so I pulled it out to inspect. No shaft play, impeller is fine yadda yadda. Had two loose bolts tho so figured the o ring might have failed. Got a new one and still have this horrible leak. Plus when I refilled and bled I got this lovely black oily foam coming out the bleeder screw in the rad. Thought I might have a HG issue but see no water in the oil, no white smoke from exhaust and car seems to run fine.

Can the experts chime in and confirm my fear that this is my profile gasket that has taken a dump?? Any useful tips/DIYs to replace? You really have to take the freakin head off?!???