My sensor is leaking.

The FSM does not give a specific procedure for replacing the sensor, only how to R&R the oil filter tower while the engine is on a stand.

Anybody been there before, and have any tips for how to get to it?

John vstech and I looked it over last weekend and we are stumped.

From above looks near impossible
From below looks like you have to pull the starter

Anyone? Bueller? gsxr?

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I can't remember whether I pulled the sender or just looked at it, back in the days when I was designing an oil pressure alarm for my '87 300D Turbo (since sold). I don't recall any difficulty removing the sender and definitely did not require removing the starter.

The sender on the OM606, a similar block, is awkward to R&R from below and cannot be accessed from above unless the intake manifold is removed, but there's no real problem unless you allow your wrench to short the starter electrical terminal to ground (disconnect the battery first). I don't remember what sort of wrench is required, only that it's awkward. You'll lose a little oil, be prepared to catch/mop, but it doesn't require draining the oil first.

The photos show (from below, belly pan removed) the OM606 block in the W210 chassis (1996 E300). This model has no oil pressure gauge so the block is plugged. This is not what your engine looks like but it is similar and these are the only photos I have.

Jeremy

Attached Thumbnails

   

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I had to use a crow foot with a u joint.

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

This thread has a few hints:
Oil pressure anomolies... hope I didn't just destroy my car

but the main place you want to go is post 10 of this thread:
603 Oil Pressure Sending unit

I tried from below and failed. The method in post 10 seems like you have to remove a lot to gain access from above, but it was easy (and I am a beginner). I didn't follow his first step though, and everything went fine.

__________________
1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).

Thanks guys

I got it out yesterday after pulling the IM and the fuel preheater. I just detached it from the port in the head, I did not undo the fuel lines, only the incoming heater hose. Had to drain about a 1/2 gallon of coolant to keep it from pouring out then stuffed a clean rubber glove into the opening to keep it from dripping.

The old one was definitely shot, it was oozing oil from the joints.

New one working much better, actually shows the pressure changes at operating temperature idle now. The old one was pinning the gauge at 3 all the time. Now I wonder if it was shorted and it was never giving any actual oil pressure

Just to be sure this is right: after engine warms to operating temperature (just north of 80C) the pressure drops to a hair below 2 sitting at a stop light. As soon as you accelerate away from the light it instantly jumps up to 3 and stays there.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

yup, that's the way the pressure is on a decent OM engine. actually it's allowed for the oil to drop to .5 at hot idle. as long as it jumps back to 3 above idle.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!