M42 Profile/Head Gasket

Post Fri Jul 06, 2012 2:45 pm

So I've been seeing a nice trail of white smoke from my exhaust for a day or so now, so I finally built up the courage to if my wildest dreams have come true.

Mayo in the oil. Yay!

The automatic response to this is always usually to replace the head gasket, however with the addition of the profile gasket on the M42 it brings the question - which one is gone, or both? Anf if replacing one, should I just replace both? Also from what I can tell they are the same thing?! Is the profile gasket not normally part of the head gasket?

Post Sat Jul 07, 2012 5:00 am

Could be either! When the profile gasket went on mine the water just pissed straight out and down the side of the engine, no oil/water mixing.

You want to be replacing both if you taking the head off, i'm guessing the profile gasket probably doesn't come with a head gasket set.

Post Sat Jul 07, 2012 7:47 am

AFAIK all M42s still running will have had the profile gasket changed already

Post Sat Jul 07, 2012 9:41 am

DHFiS wrote:AFAIK all M42s still running will have had the profile gasket changed already

It doesn't mean they can't go again. Corrosion around the profile gasket mating surface is often an issue at this stage

Post Sat Jul 07, 2012 1:06 pm

Records state that the Head Gasket has been changed many times over the years, no mention of a profile gasket, but then again a lot of people call them both the head gasket. I guess while I'm stripping the head off I may as well do the two...

Post Sat Jul 07, 2012 1:37 pm

cee wrote:Records state that the Head Gasket has been changed many times over the years

In that case, there's probably an underlying problem that's not been addressed.

Post Sat Jul 07, 2012 1:39 pm

Brianmoooore wrote:
cee wrote:Records state that the Head Gasket has been changed many times over the years
In that case, there's probably an underlying problem that's not been addressed.

Hmm if I remember correctly it was only around 4 times, I didn't consider 4 in over 20 years that bad..?

Post Sat Jul 07, 2012 1:48 pm

I dare say either the head or timing case is badly corroded around the profile gasket area and the head gasket is being mis-diagnosed. That was the issue with mine.

Post Sat Jul 07, 2012 1:52 pm

Kedge wrote:I dare say either the head or timing case is badly corroded around the profile gasket area and the head gasket is being mis-diagnosed. That was the issue with mine.

Ugh it's never simple is it...

Post Sat Jul 07, 2012 3:17 pm

There are two different Head Gaskets and 3 profile gaskets listed on realOEM. What's what?

http://realoem.com/bmw/showparts.do?mod ... g=11&fg=15

http://realoem.com/bmw/showparts.do?mod ... g=11&fg=15

Post Sat Jul 07, 2012 3:57 pm

Normal one and one for excessively skimmed heads.
The profile gaskets in that link aren't the ones normally referred to as such. The 'profile gasket' is the one here: http://realoem.com/bmw/showparts.do?mod ... g=11&fg=10

Post Sat Jul 07, 2012 4:03 pm

Brianmoooore wrote:Normal one and one for excessively skimmed heads.
The profile gaskets in that link aren't the ones normally referred to as such. The 'profile gasket' is the one here: http://realoem.com/bmw/showparts.do?mod ... g=11&fg=10

Aah that answers my next question! I was confused as to why it wasn't the same as the one commonly talked about! Thanks.

Do you know which is the Head Gasket I need then (the standard one I'm assuming) is this the top one in the list?

Post Sat Jul 07, 2012 4:09 pm

If yours has had as many head gaskets as you say, and the head has been 'faced' every time as it should be, then you could well be into thicker one territory.
You need to measure the total thickness of the head to determine which is needed. I don't have the data to tell you which, though.

Post Sat Jul 07, 2012 4:13 pm

Okay fair enough. Yet even more complicated.... I hate cars!

Post Sun Jul 08, 2012 11:00 am

You may need another head. Four skims/gaskets means it is probably shagged. I have a few nice ones here.

Post Sun Jul 08, 2012 12:41 pm

Get the head down to someone who knows what he's doing, such as a FER member who skims heads, and if possible get him to look at the block as well. He will advise as to whether what you have is scrap or not, and do the necessaries if it's salvageable.

Post Sun Jul 08, 2012 3:11 pm

If you are getting a head skimmed, be sure to get the front cover skimmed with the head, you would be amazed how many people don't

Post Sun Jul 08, 2012 7:12 pm

Well I'm moving to stay with my mother for the rest of the summer (am a student) so once I get the car back there I won't need to use it for a few months as my work is within cycling distance. Luckilly her next door neighbour is the workshop manager for the local ford dealership, so I'll get him a crate of beer or something in return for giving me a hand.