On a 1987 300SDL. It was leaking badly when I bought the car, so I replaced the O-ring with a new one from the dealer, and if anything it now leaks worse. What did I do wrong? I got it at least reasonably clean, and I couldn't see any damage.

I could have sworn they had two seals, but that is probably incorrect since I resealed mine over 10 years back.

Sensors themselves and do leak. I cannot imagine a fresh one running more than $50 for a good brand. Torque is probably quite low, fasteners are M6 from memory.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

oil level sensor plastic fatigue or have hair line cracks. A lot of the time is the plastic around the middle connector. You need a new one. Alternately is to degrease the middle and fill it with rtv. It will buy you 1 year or 2.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

Get the real MB sensor. Don’t mess around with the aftermarket one or you will be doing it twice. BTDT.

You will have to get the o-ring separately with the genuine MB sensor. The aftermarket one includes the o-ring.

When I installed the aftermarket sensor I saved the MB o-ring I had ordered since the sensor came with one in the box. When I had to do it again at the next oil change (it was giving false low oil alarms) I only ordered the sensor from MB. Good thing I had saved that o-ring.

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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

Thanks, I ordered a new sensor and I will try that. A factory one cost $58, so not too bad.