Author Topic: M42 Head Gasket Leak or Damaged Head (Read 3530 times)

waldo · « **on:** February 12, 2010, 06:04:41 PM »

I have been loosing coolant for awhile. After replacing the heater core the coolant hoses under the intake, I was still losing coolant. I found out that I am losing coolant on the exhaust side of the motor where the head meets the block. If I let the car cool with the front on ramps, it will leak. Otherwise no leak on cool down.

I sent some oil to Blackstone, and they report no coolant in the oil. Am I looking at a bad head gasket or is there still a chance something is wrong with the head?

KenC · « **Reply #1 on:** February 12, 2010, 06:59:42 PM »

Could be a bad headgasket. Pretty easy fix. Gasket and bolts are kinda spendy though.

Michael_B · « **Reply #2 on:** February 28, 2010, 07:46:59 PM »

I had pretty much the same issue with losing coolant with no leaks or oil contamination. In my case it turned out to be a small crack in the seat on one of my exhaust valves. I found a great shop near me that specializes in cylinder heads that was able to install a new seat and weld the crack.

Phreon · « **Reply #3 on:** March 01, 2010, 06:25:11 PM »

Hey Waldo,

If it's leaking towards the front passenger side of the engine it is probably a bad timing case profile gasket. Very common problem on the M42. Mine just blew last week and I spent 14 hours taking off the head and replacing the gasket. Local shop wanted $2,000 to do the work and extra if they had to replace other parts.

Parts are about $200, mostly gaskets, from Pelican. If you do it yourself you will need ...
head gasket set
set of torx head bolts
new exhaust manifold studs and copper nuts
some fuel line hose (1 foot)
some vacuum hose (2 feet)
some RTV sealant

Do a search and you will find the relevant links like ...

http://timthurber.com/tcpg.htm

http://www.pelicanparts.com/bmw/techarticles/101-Projects-17-Head-Gasket/101-Projects-17-Head-Gasket.htm

and of course the Bentley manual.

Takes about 8 to 10 hours to take it apart and clean and prep the parts.
Takes about 4 to 6 hours to put it back together.
It comes apart pretty easily except for the exhaust manifold, that is a B*&#H, both getting out the studs and then getting it back together. Probably took over an hour to get it off and 1 1/2 getting it back on.

Mark all of your hoses and wiring connectors with masking tape with where they go. Use a digital camera to document what you took off.

I just finished mine today and I just started it up. Runs terrible, hope its just the computer trying to relearn the settings.

Good luck Dude!