Hi all,

I have a 2011 E550 sedan. In May, I replaced all 4 camshaft position sensor and 4 camshaft magnets preventively. I bought Bosch camshaft position sensors from FCP Euro. For some reason, one of these sensors keeps weeping a small amount of oil after replacement. The sensor in question is on the left side, and is top side, I believe its the intake side. The 3 others are dry. It is leaking a very small amount, essentially a small weep out of the bottom side of the sensor where it goes around the bolt. I have replaced the gasket, it still weeps. I then bought another new sensor and gasket to rule out the sensor itself, it still weeps.

Any ideas? Thank you.

 

It sounds like it's coming back out from the harness side.
How about install the pigtails on these sensors? if you do it now, it will help you either way.

What's the condition of your crankcase vent?

 

Thank you for replying. I wasn’t aware of the pigtails, thank you for bringing this to my attention. I found the below link on fcp euro but these appear to be for the adjuster magnets, not the camshaft position sensor. Do you have a link to the camshaft position sensor pigtails by chance? I don’t have any leaks from my crankcase vent valve but it’s likely original (car has 41k miles on it).

link: https://www.fcpeuro.com/products/mer...des-2711500156

 

I don't have the link to FCP CPS pigtails. Other good on-line retailers may cary this item.

I am positive there is a CPS pigtail... because hot CPS sensors are the oil-in-harness champions ahead of solenoids.

 

remove the harness, you're going to use THE ENTIRE CAN, it's going to penetrate up the harness and bring the oily mess down with it.

 

I'm unable to find anything on camshaft position sensor pig tails. Only coming up with pig tails for the adjuster magnets.

 

Also I would like to clarify I don't see any evidence of oil in my connectors/harness. I am doing this maintenance preventively. The car has 41k miles on it and I replaced everything before it started leaking. Once I replaced this camshaft position sensor in question, it weeps ever so slightly from the bottom where the bolt connects.

 

tighten it a smidge

 

It sounds like the sealing surface may have a scratch or defect keeping it from sealing completely, don't try to fix, you will only make it worse. Don't ask me how I know. You may need to apply a very thin layer of Permatex Anaerobic gasket maker above the O-ring seal, on the flat flange surface of the sensor that bolts to the valve cover. Don't use anything else as the anaerobic sealer never really hardens and is easier to remove. It sounds like the sealing surface (in the hole) may have a scratch or defect keeping it from sealing completely, don't try to fix, you will only make it worse. Don't ask me how I know. Hope this helps.

 

thanks for your feedback! Did using the gasket maker solve the issue for you? Sounds like you’ve been here before

 

Yes, the Anaerobic sealer hasn't leaked in 2 years so far.

 

Wanted to follow up here. Your suggestion did the trick! Thank you so much.
If anyone else has this issue in the future, the permatex anaerobic gasket maker is the fix. Thanks again @Rickman30

 

Pigtails to help oil wicking up the harness. Mfr. PN: A2711500156

 

WAIT...... I see these are 2x wires, right?

That may work with VVT solenoids but guaranteed not to for 3x wires CPS.

 

One thing you could do I mean it’s a longshot is just remove it spin it left and right a few times and then reinsert it. Put some grease on it and reinsert it. I have a leak on my rear camshaft hole. They made out of plastic and they have an O-ring, but it never seals properly no matter how many I’ve put in. And it leaks more in the winter time than it does in the summer because the block needs to expand. Once it gets nice and hot, it doesn’t leak anymore so the first 15 minutes in the winter it’ll leak a little and then stops.