OM 603 Fuel Heater Pipe Elbow - PeachParts Mercedes-Benz Forum

gskurka · #1 05-05-2009, 10:22 PM

Gentlemen:

I'm in the process of installing the cylinder head on my '91 350SD. The Mercedes cylinder head R&R procedure (01-415) indicates that a new O-ring should be used when installing the (fuel heater) pipe elbow into the cylinder head. How is the "pipe elbow" disassembled to change the O-ring? Does this thing just pull apart? I'm assuming that the O-ring that was included in the cylinder head gasket kit is the one I should be using.

Thanks in advance.

Greg

mplafleur · #2 05-05-2009, 10:31 PM

There is a large C-type clip that needs to be pulled out that holds the pipe in place against the head.

gskurka · #3 05-05-2009, 10:44 PM

Thanks for your reply. The pipe has been removed, along with the retainer. The procedure indicates changing the O-ring inside the pipe elbow. I need to know how to disassemble the pipe elbow to access the O-ring.

Greg

CANDIDE · #4 05-06-2009, 01:09 AM

Quote:

Originally Posted by gskurka

Thanks for your reply. The pipe has been removed, along with the retainer. The procedure indicates changing the O-ring inside the pipe elbow. I need to know how to disassemble the pipe elbow to access the O-ring.

Greg

The O ring is not inside the pipe, its resides in a groove on the cylinder head end of the pipe, assuming it hasn't decomposed and its remains left in the head.

Removal:
Pull up on the clip located at the head with a hook. The water pipe will be free of the head and the O ring will be visible. Remove and discard the old O ring.
Installation:
Coat the new O ring with proper coolant, push into pipe groove. Push water pipe, with new O ring into head then push retainer clip down, such that it connects the pipe flange to the head.

gskurka · #5 05-06-2009, 10:00 AM

Thanks Candide. I removed the clip and unscrewed the threaded portion from the head. Evidently, I should have left the threaded portion in the head and simply pulled the water pipe out. I'll take a closer look later today.

Greg

Bob Albrecht · #6 05-07-2009, 11:43 PM

Why do you have the head off? What happened with the turbo?

gskurka · #7 05-08-2009, 09:37 PM

I had to remove the head because the exhaust manifold stud nearest the firewall was broken off about 2mm below the head surface. I tried drilling the stud and using a screw extractor, but the drill went off to the side and part of the hole was drilled into the aluminum head.
In retrospect, I should have tried tig or mig welding a nut to the stud remnant. Another method would be to use a bushing to keep the drill concentric. If you need to remove the head, new bolts and a head gasket kit will set you back about $400.
Everything is back together and "Old Smokey" is back on the road. I must be getting old because I still like the way this car drives, especially on the interstate. I was driving my BMW 535i with a five speed while the 350 SD was in dry dock.

CANDIDE · #8 05-09-2009, 01:35 AM

Quote:

Originally Posted by gskurka

Thanks Candide. I removed the clip and unscrewed the threaded portion from the head. Evidently, I should have left the threaded portion in the head and simply pulled the water pipe out. I'll take a closer look later today.

Greg

Yeah, you didn't need to remove the threaded fitting from the head, easy to reinstall though. I just did mine and the memory is fresh. Major PITA is reinstalling the fuel lines that attach to the oil filter housing. I used a tension wire to pull the mounting bracket holes concetric with the threads in the oil housing. If you can avoid removing the two bolts that connect the rigid fuel hose to the oil housing, you will save time.
Also, a 3x8" air wrench accelerates many repair tasks, especially the fuel line warnmer bolts that tough to get to. I've used it many tines where a ratchet wrench would only allow 1/4/ turn per action.

I think I paid $3 per stub x 26= 78 + 90 (standard victor rienz gasket kit).
I measured my existing studs and the measured ok, but for the labor and cost involved, I went with new studs, to be safer.

gskurka · #9 05-09-2009, 03:27 PM

For tough to reach bolts, I've been using a set of Craftsman Gear Wrenches or a wobble extension with the appropriate socket. Using masking tape to hold a bolt or nut to the wrench also helps. When it doesn't, I've got the telescoping magnet and a flashlight. It's not so effective with the stainless steel nuts used around the turbocharger though. Ask me how I know............

Thanks again for the O-ring instructions. I might have been stumped for a week on this one. I found that lubrication with coolant was the trick to pulling the assembly apart.

Next repair job on the horizon will be ball joints. The front end is starting to creak on small bumps and the rubber boots are kaput.