Catastrophic Failure due to oil sensors leak
For anyone else replacing the cam solenoids, it is possible to access the bolts for the filter housing without completely removing those two coolant lines. I disconnected them from the water pump and unbolted the two brackets, and was able to flex them enough to get a tool past them. I wouldn't say this is the best method because of how easily the lines are damaged, but it is possible. In my case, the previous owner replaced the coolant lines at around 55k miles, and the pump started leaking on me around 70k.
I discovered this dreaded oil leak in my car a couple months ago. There was quite a bit of oil in the cam sensor connectors and a small amount in the solenoid connectors. The rest of the top side of the harness was clean, but I haven't checked that sensor on the bottom of the engine. I replaced the cam sensors at the time, and just cleaned out the connectors on the solenoids. I just replaced the solenoids this week, and the connectors were all still clean.
Being curious about why these fail, I hacked apart one of the old sensors to see if I could figure anything out. I initially thought there were unnecessary holes in the sensor, but it all appears to be sealed. The only thing I've found so far is several large air bubbles in the plastic, which makes me think it was an injection molding problem.
Searching for 250 in the diagram, part # 157-200-00-51, it came up 157-200-01-51 but when I select this part, it says not fit for my car. I will have to remove it and bring it to the dealer.
This is the second bracket by the turbo that holds the 2 coolant lines.
Last edited by dustinN; Jun 10, 2022 at 07:21 PM.
That's the correct part number for the center line. I bought it from FCP Euro because of their lifetime replacement deal.
The Best of Mercedes & AMG
Last edited by dustinN; Jun 11, 2022 at 09:39 PM.
By the yellow lines at the bottom of the pic where it holds the 2 oil lines? Now I know where it was but still not 100% sure about the position and angle. Do have a clearer picture?
My first time tackled a big project like this. Should have taken lots of pictures before removed anything. Much appreciate!
when you pick up your car do you mind asking the tech or whomever if oil in harness can cause a p0420 code. That’s what my dealership is telling me but doesn’t sound right.




By the yellow lines at the bottom of the pic where it holds the 2 oil lines? Now I know where it was but still not 100% sure about the position and angle. Do have a clearer picture?
My first time tackled a big project like this. Should have taken lots of pictures before removed anything. Much appreciate!sorry, no picture ability as my car is in because of a deer….. that pic was in my phone. If you look in the area you will see two clamps around the pipes that will have holes and they may help you align the bracket. Also if you look down at the block while standing at driver front wheel, right at the corner you will see I think three empty holes and it aligns with two of them. They are on the edge, right behind the cam end cap.
Last edited by JEC_E63S; Jun 16, 2022 at 09:07 AM.




Last edited by Baltistyle; Mar 1, 2023 at 03:36 PM.




