I was actually surprised to find the sender switch to be mounted below the oil level making the gasket critical to prevent leaks. I figured they would mount it above the oil level and let it dangle and therefore the seal would be much less critical only stopping splashed oil from escaping.

In my case the gasket was shot, but I have heard that sometimes the switch itself leaks. You should be able to tell if it is coming around the edge or from the center. On my car it was an easy fix...two bolts hold the switch to the side of the engine and the rubber seal is on the back. I replaced the gasket and put some sealer around the outside for extra measure too but I could see the defect in the gasket when I removed it.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz