Infamous profile gasket

[idickers]

I need help determining if I need to replace my profile gasket. I have a '91 318is that I rescued form serious neglect by the previous owner. I just took off the timing cover to replace the timing chain and guides, and noticed a gasket bulging out from the junction between the head and the block (yellow arrow).


Is this the infamous profile gasket that caused so much trouble? I have no way of verifying if this has been replaced; is there any way to tell?
Thanks for any suggestions!

[series88]

Since your already almost there, I say, just do it. They always fail.

[idickers]

Do I need to remove the head to replace?

[series88]

I honestly don't know. I unfrotunately had a shop do mine because landlord does not allow car work at my place.

[bmwman91]

Although 95% of M42's out there already had the bad original one replaced with the updated one, it is definitely worthwhile to replace it anyway if it is of unknown age and condition. Bulging out like that is somewhat normal, but you can usually feel it bulging on the inside too. If it is actually starting to blow out the front, then you definitely need to replace it.

You do not need to remove the head to replace it. However, after replacing three of these with the head on the car (you have to remove the timing case instead), it is most likely easier with the head off of the car. Getting the timing case off requires you to remove the upper oil pan, which is a royal pain (re-sealing the new pan gasket sucks too). Putting the timing case back in with the head there is also a huge pain since you need to use a jack to push the timing case up to compress the new gasket, get the oil pump gear aligned with the crank and rotated into position, and the upper profile gasket won't want to go in as it catches on the head's leading edge. I found that buying a big piece of 0.005" brass shim stock and lubing it with silicone grease was the only way to do it...you put the shim on top of the new gasket and then slide everything under the head and pull it out once it is in place.

So yeah, I am getting long-winded. Pulling the head is easier, and you'll get the new gasket in better position that way. The ONE reason to pull the upper oil pan anyway is to check and replace the oil pressure bypass valve that is clipped into the timing case. The original metal one had a tendency to seize, which causes oil pressure loss.

See parts 5-8

http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=11_0504&hg=11&fg=30

Honestly, you might as well pull the head and move the upper oil pan (I think you can get at the bypass valve by unbolting the pan and sliding it out of the way).

[idickers]

Although 95% of M42's out there already had the bad original one replaced with the updated one, it is definitely worthwhile to replace it anyway if it is of unknown age and condition. Bulging out like that is somewhat normal, but you can usually feel it bulging on the inside too. If it is actually starting to blow out the front, then you definitely need to replace it.

I checked, and the gasket is bulging on the inside as well as the outside, so perhaps it is just normal appearance for a squashed rubber gasket. The rubber does seem to look to new to be 30 years old. Perhaps I dodged the bullet on this one:D