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leaking magnetic cam adjusters sensors

thamesc180k

Active Member
Joined
Nov 1, 2024
Messages
86
Location
New Zealand
Car
04 c180K
hello all, can someone explain how the oil stop harnesses for the leaking magnetic cam sensors work?
does the oil run along the outside of the wires insulation, to say the ecu, and cause damage/short circuits?
if the sensors leak from their housings can one "bung" a gasket sealant around the housing, to stop it leaking, rather than buying new ones?
Surely the oil must seep around the outside of the sensors and not internally as they would be sealed?
Thanks , just trying to understand what the issue is.
 
hello all, can someone explain how the oil stop harnesses for the leaking magnetic cam sensors work?
does the oil run along the outside of the wires insulation, to say the ecu, and cause damage/short circuits?
if the sensors leak from their housings can one "bung" a gasket sealant around the housing, to stop it leaking, rather than buying new ones?
Surely the oil must seep around the outside of the sensors and not internally as they would be sealed?
Thanks , just trying to understand what the issue is.
The oil seeps through the cam magnets and then through the electrical connection where it runs along the wires to the ECU and the O2 sensor which is a low point .
The wire blockers prevent the oil running along them when the cam magnets leak .This happened to me and an engine management light came up , fortunately I had blockers on so just changed the cam magnets for new ones .
IMG_0765.jpeg
 
This was the fault code and repair
 
The oil seeps through the cam magnets and then through the electrical connection where it runs along the wires to the ECU and the O2 sensor which is a low point .
The wire blockers prevent the oil running along them when the cam magnets leak .This happened to me and an engine management light came up , fortunately I had blockers on so just changed the cam magnets for new ones .
View attachment 163992
The oil seeps through the cam magnets and then through the electrical connection where it runs along the wires to the ECU and the O2 sensor which is a low point .
The wire blockers prevent the oil running along them when the cam magnets leak .This happened to me and an engine management light came up , fortunately I had blockers on so just changed the cam magnets for new ones
This was the fault code and rep
im still none the wiser, so where does the oil leak from specifically?
it may not look original but can you seal the leak before it reaches the connector/plug? then there is no need for harness blockers?
 
im still none the wiser, so where does the oil leak from specifically?
it may not look original but can you seal the leak before it reaches the connector/plug? then there is no need for harness blockers?
I would guess from within the magnet itself , it doesn’t leak past the large outer o ring , so unless you can take the magnet apart and do something I don’t know buddy .
I can say in 10 years on the forum and being an M271 owner for 12+ years I’ve never heard of anyone doing a fix like you suggest . Even if there was , it would seem to be a time limited repair ?
New cam magnets and some wire blockers aren’t particularly expensive in MB fix world .
 
yes true, they arent costly , just thought they might be sealeable.
i think ive mentioned ive replaced the orings but it mightnt be where theyre leaking oil from.
i havent had the car back up and running yet, idler and tensioner to do.
thankyou for the information
 
The issue isn't the leaking sensors per-se, because fitting new camshaft position sensors isnt an expensive fix, instead the issue is that the oil can get down the wiring harness and wreak havoc on electrical components e.g. the ECU which can write off an older car.

The wire extensions won't prevent the camshaft position sensors from leaking oil, obviously, but they will stop the oil from getting into the wiring loom.
 
0117081610.jpg


0117081609.jpg
 
Shortly after I bought the W203 C200 with the M271 engine, I noticed oil leaking from both cam magnets.
I changed both cam magnets and added the two pigtails as oil blockers.
Fortunately, the oil had not gone far enough to cause any serious damage.
A cheap fix and simple to do yourself.
 
The issue isn't the leaking sensors per-se, because fitting new camshaft position sensors isnt an expensive fix, instead the issue is that the oil can get down the wiring harness and wreak havoc on electrical components e.g. the ECU which can write off an older car.

The wire extensions won't prevent the camshaft position sensors from leaking oil, obviously, but they will stop the oil from getting into the wiring loom.
two questions then
1. can you seal around the sensor or do they leak from inside the plug/connector through to the wiring?
2. is it just because of the length and the loop made of the 'oil blocker' harness that stops oil travel?
im trying to understand where or on what the oil travels. Is it inside the looms or just on the outside of the loom?
 

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