Can anyone advise me best way to get to the oil pressure sensor on my 1995 E320 Coupe. It has M104 engine - and although I can see sensor at base of oil filter housing - it looks like it's almost impossible to get to it to remove it and replace it with a new one. Any special techniques or tools that might help??

I have the same M104 in my 93. Did the oil pressure sensor swap two summers ago.

Despite the tight confines, it took around 15 minutes to do it. You just need a crescent wrench (I forget what size, but since you have the part at hand, you can test fit).

There is just enough room to get one hand in that area where you can feel for the loosening point on the old sensor with your hand and dexteriously work the wrench over to the spot. Not much room to crank the wrench either, but it doesn't take many turns to get it loose enough to remove by hand at this point. A short wrench works best. A really long one won't work.

Got the part and waited a few weeks after to do the install because I feared what you did...too hard to do. But it's surprisingly easy!

Oh yeah, no worries about oil pouring out on top of you while you do this either!

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Is this the clue that access is from below?

Agree with G-benz,,,, not a big deal. Did this last year and after having the oil pump replaced, this turned out to be the problem with the guage reading low oil pressure.

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95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K

Oh yeah...that's important to mention I guess. Gotta crawl under the car to do this. So add "removal of plastic engine compartment pan" to the list of procedures...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Thanks for all the replies. Still don't know if I need to change sensor yet - but my oil pressure gauge started reading lower and lower over the past week or so (now reads about 1.8 bars@ 2200 rpm - so I'm suspecting the sender is going bad.

I made up an adapter tool (see attachment) from a spare oil filter housing cap so I can hook up a mechanical oil pressure gauge and see if it agrees with what my sender/gauge is showing. I'm hoping it's the sender - and not the oil pump. Engine seems to be getting oil ok - & looking into oil filler cap opening shows lots of oil flying around inside to lube the cams.

Once again - thanks for all the help - this tech forum is really a great source of help and support for all of us MB Do it yourselfer's

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The sender is a more frequent cause of oil-pressure reading anomalies for the W124 models...and a far cheaper fix!

Oil pump failures are rare on the W124...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

which oil pressure sender did you buy?
the more expensive VDO($70+) or the cheaper HamburgTech($ 30+)

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Tom 2010 C250 4-matic Sport (Canada)

I bought the OEM from Fastlane...paid close to $70, I believe.

If the difference was hundreds of $$$ on a non critical component, I sometimes hedge and get the generic counterpart. The $30 part might be just fine, though...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Went that route for the evaporator for the 400E. Fastlane was about $400 less than OEM. It took a little tweaking to get it to fit, but all seems good after 6 months.

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95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K

I noticed that on my '91 300SE the oil pressure wasn't reading right, no unusual engine noises but while I was under the car at the last oil change a couple of days ago I did notice that the sender might be where my oil leak problem may be. I'll let ya know. Thanks everyone

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1991 300SE (my ride, 279,000 miles, looks almost new
1954 Cadillac (21 yo son's car, he bought when age 15)
1972 SeaBird 19 ft runabout (old but solid, slant six, Volvo sterndrive perfect condition, undergoing complete overhaul and refit)
1998 Toyota Rav4 (my sons daily driver when he is in the Continental US, PROUDLY serving in US Navy)