EGR Blocking Kit on 617 CA Engine DIY w/pix - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 07-05-2007, 03:43 AM

[Part 1 of 2 parts]

I had intended to install Brian's EGR test kit on my California version 1985 300D Turbo during removal of the Trap Catalyst for testing purposes. However, when I discovered that the flex pipe from the trap cat to the EGR valve was cracked and leaking, I decided to go ahead with the EGR kit and do the Trap Cat at a later date, when the test pipe was available.

Brian had expressed concern about installing his EGR kit on a 617 engine equipped with a trap cat -- he was not sure how the EGR port on the trap cat was configured. In fact, it worked with no problems. Here is how I did it.

The first photo shows the plumber's nightmare that greets all owners of the catalyst-equipped 617 engines. The EGR valve is partly pinned by the tubo and partly by a bracket that supports an air conditioning hose. The bracket must come off to get at the EGR screws. It would be a lot easier if the turbo was also off but I was trying to avoid that and managed to work around it.

The first step is to remove the air cleaner cannister and the rubber flex pipe that takes clean air from the filter to the turbo inlet. Cover the inlet to keep dirt and parts out of the turbo.

The second photo shows the trap cat, buried under the turbo. In the 603 engine, all that stuff is up where you can get at it. Not so with the 617-CA. Working room is seriously cramped by the pipes and hoses associated with the auxiliary water pump as well as the turbo oil drain pipe. You can see the patch I had hastily applied last week to keep the flex pipe together for a few more days.

The third photo shows the bracket that supports the A/C hose as it runs across the front of the engine. The photo is actually an "after" photo; the bracket was so dirty you would not have been able to see it, much less recognize it. The two bottom bolts hold the bracket to the block while the top bolt holds the A/C line. With the bolts and bracket out, the bottom-most hole dribbled coolant so I put the bolts back in loosely.

Even with the bracket gone, the EGR valve is still cramped by the turbo. The bottom EGR bolt (6mm Allen head cap screw) is fairly easy to get at with a long Allen key or, better yet, an Allen key on a 3/8" drive with a 6 inch extension and a short ratchet handle. The top bolt is a real bugger. You can hardly see it, much less touch it. The waste gate line and its fitting prevent you from inserting a standard Allen wrench. Fortunately, I had a ball-end metric Allen set bought many years ago because I thought they were neat. The set paid for itself today and made a miserable job easy (see the 4th picture).

Once the EGR valve was removed, I was able to compare it to the valve removed last week from my 1987 300D (603 engine). The two valves are identical.

This means that the copper disk supplied as part of Brian's kit will fit the port on the trap cat with no modification.

The clamps used in the 617 engine are stiffer than those in the later 603 engine and at first I thought that I would use the left-over clamp from the 603 EGR project. However, I discovered that the stiffness was not a real problem and as a side benefit the screw was easier to get back into the clamp without cross-threading -- Brian warns of this in the 603 kit.

[to be continued]