Oil pressure sender?
 

Been monitoring a small oil leak on my 420SEL thats popped up in the last 3K miles/6 weeks. At first I thought it was from the filter housing O-ring as there was a little seepage from there. I know the O-ring that came with the WIX filter was a fraction smaller in rubber diameter. ( I'll never use another WIX for that reason.) But now I'm pretty sure it's eminating from the oil pressure sending unit under the filter housing. Because theres lots of splatter on things beside and behind it (in relation to the front of the car). Can't seem to catch it in the act while idling, so I'm thinking it does it while under throttle.


Does this seem logical? Or should I focus on something else? It's a pricey item to change if it's not the culprit.

Cliff

There should be a repalceable o ring for the sender unit, it is usally the leak not the actual sender.

does that go for 88 300se ? on my oil pan driver side there is a sensor/sender and its leaking pretty bad .. new sensor/sender or most likely a o ring ?

"does that go for 88 300se ? on my oil pan driver side there is a sensor/sender and its leaking pretty bad .. new sensor/sender or most likely a o ring ?"

Yes, you can buy just the "o" ring(s) from dealer.
Best to drain oil first.

NOTE The oil pressure sender is part of the Battery [aka"B"] Harness for Starter and Oil Pressure Sender. Check condition of wiring, because it has same problem as main engine harness. If wire insulation is bad, it's easy to make new set.

If your oil level light is not coming on then the sender readings are good, it just leaks. If the wiring insulation is good and the sender reads correctly, just get the o ring and it will stop leaking. Easy easy to replace. Two bolts and it comes out, replace o ring and reinstall. too easy. Do it when you change the oil.

i get free oil so i think ill do it when i knock out my tranny gasket ... i take it that when you remove the sender the small plastic piece that sticks out seperates from the metal housing that has the two bolts that hold it in .. any chance its a standard gasket size cause i have a couple sets of o-ring gaskets and hoping it will be a size i have ..

everytime I try to use an o ring I already have left over rather than the correct one, it turns out that it was not correct and it still leaks and I end up getting the correct one any how. I would get the correct one for less than a dollar instead of using one that might leak also.

dealership has them for under a buck ? and what about when you take it off ? does the plastic sensor that sticks out seperate from the housing that the two bolts go into ?

well seems i solved it for free :D .. gotta love my boss for previously owning a napa store ... has lots of nifty stuff around our shop

mine was leaking from around the plug in .. and of course i threw a new gasket on


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