I am removing the front cover on a M104, all the wire harnesses have been unplugged, and the bolts removed. There is a plug on the lower right side that was removed to expose a internal threaded bolt. Does this internal threaded bolt need to be removed in order to remove the front cover? Here is a picture of the upper front cover.

http://www.geocities.com/ctjohnny81/M104bolt.JPG

Welcome to this site.

I can't access the image. Is this a pin on the driver's side that holds the guide rail in place? I don't think it's necessary to remove it to remove the upper timing cover. Once you break the bonds of the mating surface, the timing cover should slide forward and off.

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95 E320 Cabriolet, 169K

Look at the pictures here: http://www.continentalimports.com/ser_ic100345.html

The pin shown in the front of the head has not been removed to get that far. It is necessary to remove it to remove the head (which is the only real way to fix your leak), but not to get the cover off. It does make the installation kind of a pain.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Thanks for the information.. I will let you know how it turns out.

The cover was removed easily without removing the pin, I do understand how it will be easier to install the cover without the pin. What sealants are recommended to seal the cover back to the front of the engine, as well as the sealants used on the u seal at the bottom of the front cover.

My son assisted me today in removing the upper timing cover from my 96' E320 but got frustrated when I decided to wait until I heard from the experts about the necessity of pulling the chain tensioner pin to remove the cover. So, I posted this question in this forum and told him I'd wait before proceeding.

'Unbeknownst' to me, he registered on the forum, took a pic, and posted the same question, (CTJohnny) A pic. must be worth a thousand words because he got immediate response and we removed the cover after a little more effort on pin side to free it.


Thanks to all that replied with this info.

Steve's link lists the sealants used for the job, though the MB numbers are different from the ones in my manual. Perhaps MB updated the required sealant formulation since 1995.

Steve lists PN 002 989 47 20 10 used for the metal-to-metal surfaces and PN 001 989 61 20 10 used for the dabs in the corner.

My notes from the manual and previous posts show PN 002 989 73 20 10 specified for the job, and that this is similar or equivalent to Loctite 5900 and 5999. I don't think the regular rtv sold over the counter at your local auto supply house can perform properly for this job.

DON'T use sealant on the U-shaped seal, except at the corners. I suspect this design requires the surfaces to move during operation with thermal cycling. I put a light coating of silicone to aid installation. I don't feel comfortable installing any seal dry.

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95 E320 Cabriolet, 169K

I was wondering if you still have a leak and will have to replace your head gasket.
(Sorry--I must have hit wrong button and made the other post.)

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TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

My M104 upper timing cover wasn't coming off very easily, so I started trying to remove the guide pin. (I see from Steve's post above that I should be able to remove the cover first; nevertheless, I'll need to remove the pin sooner or later.) I tried a 12-24 bolt and it screws in about 1/4 inch, which should be sufficient. I tried an M6-10 and it goes in about 1-2 turns. The hardware store only carries M5 in 0.8 pitch. I'll try it, but I'm guessing I need either M5 or 5.5 (is there such a thing?) in 10 pitch. tia.

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TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)