Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 03-26-2001, 08:45 PM
Registered User
Join Date: Jan 2001
Location: Tucson, Arizona
Posts: 758
Greetings All, Reference made to a '80 300TD Station wag.

Anyone out there with injection pump troubleshooting experience please respond. I am trying to solve my oil losses one at a time, and conquered the biggest one so far, the vacuum pump diaphragm which was sucking oil and sending it to the air filter housing, but there is a second one that maybe coming from the injection pump to the key switch. I find oil on the underneath of the ignition switch generally after about 80 mile of driving. Just a drop or two, but would rather fix the problem now. The engine seems to shut down rather quickly after turning key off, but after pulling vac line off shut down diaphragm, I see traces of oil. Is it sucking oil from injection pump through a leaky diaphragm? Any info would be appreciated.


To coin a phrase I also like the smell of diesel in the morning.

[Edited by can-do on 03-26-2001 at 08:50 PM]
Reply With Quote
Old 03-26-2001, 11:47 PM
Registered User
Join Date: Feb 2001
Location: Midwest, USA
Posts: 171
Charles, I would suggest checking all of the vacuum lines especially the ones going to the vacuum control valve on top of the IP. I had a leaky transmission vacuum assembly which was sucking trans fluid into the vacuum control valve. It would have eventually filled all of my vacuum devices if not caught in time. Follow the vacuum line down to the transmission. On the passenger side, find the vacuum valve, pull off the vaccum hose and see if you can feel any fluid leaking. Just one notion.

Cheers my friend, Patsy
Reply With Quote
Old 03-27-2001, 12:03 AM
Registered User
Join Date: Mar 2001
Posts: 326
The shut off diaphragm is probably leaking therefore sucking oil into the vacuum swith on the back of your ign switch. Remove the vac at the shut dia to see if oil is present. If so the shut off valve will need replacment. Make sure you clean out the vacuum lines.
Scott Diener
89 300E
93 300E
92 Volvo 740 Wagon aka "Mutt mover"
Reply With Quote
Old 03-27-2001, 01:16 AM
MikeTangas's Avatar
Senior Member
Join Date: Apr 2000
Location: So. Cal
Posts: 4,430
Someone also recently posted the part numbers for in line vacuum filter designed to keep oil (from leaky diaphragms) from conatminating the system. Also a good indicator of which engine vacuum device is failing.
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon least its a diesel

Non illegitemae carborundum.
Reply With Quote
Old 03-27-2001, 08:17 PM
Registered User
Join Date: Jan 2001
Location: Tucson, Arizona
Posts: 758
How Many Different shutdown valves are there?

Greetings All,

I like your idea Mike of having filters on vacuum lines, clear ones at that, would isolate many problems vacuum wise much quicker. Patsy I don't have an elaborate vacuum system on my car as others might. For the ignition vacuum circuit it takes vacuum off a three way "Y" off from the tee from the power brake booster line, goes to the ignition vacuum switch them out to the shut off solenoid on the pump. I don't have any vacuum lines going down to the tranny, all linkage driven. No vacuum valve at all located on the valve cover. I would say the constant vacuum on the injection pump shut-off diaphragm after shut down sucks just enough oil through a crack or pin hole in the rubber to pull oil to the switch, causing droplets to form on a daily basis. The stopping action of the engine is almost immediate once I turn off the key, maybe a second will go by. There is no other source of oil in the system except through the vacuum pump itself, and that was fixed last week with a huge difference in oil consumption and WA LA no oil in the air filter housing, at all.
My main question is how do you know if a new valve will fit your pump? Looking through the manual for the engine, is shows several MW style pumps, and would assume that the shut down valve is different on each of them, is this correct? How can I isolate which vacuum valve I need using the numbers located on the pump. Also, which numbers do I use? There are numbers on a plate at the side front of the pump as well as the rear side of the pump. Which plate is the tell all?


Reply With Quote
Old 04-23-2001, 08:33 PM
Registered User
Join Date: Jan 2001
Location: Tucson, Arizona
Posts: 758
Replaced Shut-off vacuum valve

Greetings All,

Just a short note to end this thread that oil in the ignition switch vacuum portion of the switch is caused exculsively by the shut-off valve. Once this little guy is changed, and by the way almost all of them seem to be the same type, there is no more oil dripping from the switch housing.

Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Wagon rear suspension valve rebuild lrg Diesel Discussion 11 10-04-2006 06:02 AM
'83 240D - Heater Control Valve Is leaking arkie Diesel Discussion 2 02-04-2004 01:00 PM
OM603 Shut Off Valve Replacement - Tips? Lance Allison Diesel Discussion 3 08-04-2003 08:32 PM
83 300 SD shut off valve replacement richclay Diesel Discussion 11 07-18-2003 08:06 PM
Valve Cover leaking Capt Kirk Diesel Discussion 7 04-28-2003 05:32 PM

All times are GMT -4. The time now is 07:09 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page