OM603 Vacuum & EDS Diagram

[Jeremy5848]

There have been requests for the OM603.96 vacuum diagram in the 1987 300D Turbo and the 300SDL. Here is a vacuum diagram from the 1990 publication of the Mercedes (paper, not CD-ROM) FSM for engines 602 and 603. Following the vacuum diagram is an electrical diagram for the Electronic Diesel System. Some versions may not have the air recirculation valve (ARV) and its associated vacuum transducer.

I uploaded the diagrams to my Photobucket account in the largest available size – they somewhat overfill the page here in this forum but that guarantees good resolution. If you download them, save them as JPEG files, and then print them out, they should fill one page each and be easy to read.

Jeremy

[Brian Carlton]

Thanks Jeremy.

Vacuum diagram added to sticky.

[Bio300TDTdriver]

The vacuum reservoir and the line going to it are missing in that diagram. If someone is trouble shooting and finds an extra line, it goes to the vacuum reservoir that is located behind the passenger wheel well. At least that is the location on a 124. I'm not sure about the 126.

[sixto]

That's right. There should be a split before the VAC port of device 123.

Sixto
87 300D

[Jeremy5848]

You're right, I didn't even notice it was missing. See this thread for pictures of the vacuum reservoir in the W124 chassis.

[monette999]

Nice schematic Thank you

[mikeyfev1]

Is the routing the same for the 1986 300SDL? The diagram says Model 126 California from Model Year 1987. I would guess that there are differences from the diagram and my car.

[Jeremy5848]

Originally Posted by mikeyfev1

Is the routing the same for the 1986 300SDL? The diagram says Model 126 California from Model Year 1987. I would guess that there are differences from the diagram and my car.

That's a good question. I agree that there are almost certainly differences between 1986 and 1987 in the W126 -- there certainly are in the W124.

Jeremy

[CarpeDiem51392]

Jeremy
Thanks so much for the vacuum diagram, it's been VERY helpful.
I'm currently chasing down a plethora of vacuum issues in my 87' 300d. Most of the vacuum connectors I've seen are in rough shape (the outside rubber is crumbling) it seemed wise to change some or all of these hoses. I haven't found any with obvious signs of leakage but I'm sure me playing with them won't help.

[CarpeDiem51392]

Wow tried to tab in and posted by accident, brilliant.

Anyways will replacing the vacuum lines with (5/32") hose from autozone adversly affect any vacuum components? I think I remeber reading some components may be affect by velocity? Which case getting the wrong hose diameter would not be good. Although if it's just a matter of "pressurizing" (negatively) the system then maybe it shouldn't matter? I could buy the correct metric hose from ebay but I don't want to wait for shipping.
Thanks!

[Jeremy5848]

Originally Posted by CarpeDiem51392

Wow tried to tab in and posted by accident, brilliant.

Anyways will replacing the vacuum lines with (5/32") hose from autozone adversly affect any vacuum components? I think I remeber reading some components may be affect by velocity? Which case getting the wrong hose diameter would not be good. Although if it's just a matter of "pressurizing" (negatively) the system then maybe it shouldn't matter? I could buy the correct metric hose from ebay but I don't want to wait for shipping.
Thanks!

It's unlikely that hose inside diameter will make a lot of difference unless the hose is so tiny that it acts as a "throttle" and slows down the air that passes through it. In that case, the things that work by vacuum would work more slowly -- transmission, etc. There are various pieces of the vacuum system, designed in by the factory, that set the rate at which air passes through the various hoses and actuators. To be safe, a general principle is "larger is better than smaller." Get whatever you can buy easily and try for "close" as to the size and you should be OK.

Jeremy

[sixto]

Make sure you keep those green and yellow fittings where they are in the plumbing. If possible, duplicate the original orientation for good measure.

Sixto
87 300D