1987 w124 om603 cylinder head bolt torque

[JustJim]

Can anyone tell me the cylinder head bolt torque for the 1987 om603 in the w124 (300D sedan)? I have found a wide range of answers searching the internet, anything from 18 ft. lbs. to 70 ft. lbs. Any help would be appreciated.

[capflya]

Here's the shop manual procedure for cylinder head R&R.
http://www.startekinfo.com/StarTek/outside/12264/Program/Engine/602_603/01-5800hx.pdf

The torque levels are relatively "low". It's the 90 degree turns that'll make you sweat. I just did this job and followed the steps in this document for the head bolt tighening/torque procedure.

1st stage 15Nm
2nd stage 25Nm
3rd stage - 90 degrees
Let bolts rest minimum 10 minutes after first 90
4th stage - 90 degrees


Make sure you chase the block threads so the head bolts will torque properly. Otherwise you may not get a good seal on the gasket.

[JustJim]

Let me make sure I understand this: tighten the bolts to 25Nm, tighten another 90 degrees, wait ten minutes, then tighten another 90 degrees. No specific final torque? Is this correct?

Thanks. Never done a Mercedes Diesel before...

[ah-kay]

MBZ does not specify the final torque value, only 90 then 90 degrees. That is enough to make you sweat. The bolt sequence is important, found it here in post 2.

Any reputable head gasket manufacturer would come with the information printout. Have fun.

[capflya]

Originally Posted by JustJim

Let me make sure I understand this: tighten the bolts to 25Nm, tighten another 90 degrees, wait ten minutes, then tighten another 90 degrees. No specific final torque? Is this correct?

Thanks. Never done a Mercedes Diesel before...

Re-read my post, and the link ah-kay and myself posted also has the info. You torque to 15Nm then 25Nm - you do not torque to 25Nm first shot. It might be fine if you did but I'm just quoting the MBZ documented info.

Originally Posted by ah-kay

MBZ does not specify the final torque value, only 90 then 90 degrees. That is enough to make you sweat. The bolt sequence is important, found it here in post 2.

Any reputable head gasket manufacturer would come with the information printout. Have fun.

FWIW I got my head gasket kit from the stealer and it didn't have the printout with the info.

[zooklm]

I am in the process of torquing the head on my OM603. I agree with capflya on the dealership head gasket set not coming with the torque sequence. Also, the copy of the manual I have gives 15Nm, then 35Nm followed by the 2 90 deg rotations.

I have competed all the torque values and the first 90 degree rotation. I had one bolt grab while doing the 90 degree. I was able to make the whole rotation, however, I am now concerned about it grabbing when I try to do the second 90 degree. I am thinking about loosening everything and starting over again. I did coat the threads (new head bolts) with oil prior to installing, however, I did not put any oil on the head where the bolts sits on the head.

Any one have any experience like this with head bolt tightening?
Thanks,
Lee

[ah-kay]

You can undo the bolts. I have removed cyl head after all bolts have been torqued down to spec. Reuse the HG after it has been installed. No damage done. Make sure all the holes are clear of any oil to prevent hydro lock when bolts are torqued down. I normally spray the bolts with WD40 before I put them on. I don't think you need to oil the cylinder head, oiling the bolts is the same.

[Jeremy5848]

A very light coat of oil on the bolt threads is appropriate—but not so much that the oil is dripping off! Chasing and cleaning the tapped holes in the block is probably the most important part of the operation. I used one of the new bolts and worked it in and out until it would go in by turning with just my fingers. I then blew out each hole with compressed air. Enough oil will adhere to the threads that you don't need to add any more.