I noticed a bit of oil in the O2 sensor connectors when I replaced them, yet didn't think much of it as it was only a small amount, cleaned them and installed.
My car has been needing < 1L of oil per 15K kms, nothing major, yet enough that I wanted to find the source.
Looked into other oil leaks on the W203 and saw the cam magnet sensors have leaked on the M111 causing oil to get into the harness.
I checked, and there's oil in the cam magnet sensors on my M271.
Luckily there no oil on the MAF sensor, or ECU connectors, so the problem might be isolated unlike the disaster it is on the M111 that ruins the ECU and requires the entire wire harness to need replacing.
Can someone do me a favor:
- pop the connectors off and look to see if there's oil on them.
- the magnets are circled in orange in this pic:
Actually, I have the M111 engine (2002 c230k), which looks different. I have a pic with the Air Filter Assy removed and do not see the cam magnets in the same place as in the M271 picture, which also seems to be less a kompressor?
Know of a good source for a diagram of parts/components. That would be helpful.
The charger on the M271 is way down and to the side, totally different spot than your M111. Sorry, I can't help you much in the M111 direction, but there are plenty of 2002 coupe owners here who should be able to help. You can also get help from the SLK forum as that is the same engine as the SLK230.
Hey i can this is mbtechgeorgia I have a new name when I get to the dealership mon i can get you a part number but if you look under the hood and take your drivers side sam cover off the harness will have a partnumber attached to it it will be white the part number starts with 271 bring that part number to the dealer and they will provide you with the cost and you can have them look up the magnets as well they will be the most up to date but i will try to get that done monday or tues and i will get you a cost
Sure appreciate the help, took a look under the hood not sure what the SAM is but I found a tag on the engine wire harnes near the aft larger connector on the control module that does get oil in it and the part number was A271-150-1833 hopefull that matches up with what you find.
How difficult is this to do for the shade tree mechanic to route the harness to all the pertinent locations, is there a lot of disassembly involved?
Hey man that part number supercedes to A271-150-29-33 but it is the right harness we had one in stock so I checked to make sure retail cost was 391.55 I can get one for about 250$, as for install, if you have never done one it's kind of a bitch you have to take off the air box, intake and supercharger to get to all the connections not really that easy if your not familiar with it but it is possible let me know
Thanks
Chris
Wow, Thanks for the info. I've taken the airbox off before and that's quite a procedure in itself. I have the official maintenance manual on CD and couldn't find a procedure for replacing that harness is there a procedure number for this? I like to expand my DIY horizons maybe I'll attempt it unless there are a number of special tools required? I'm sure there will be a number of expendable parts too, like intake manifold gasket and what ever gaskets the supercharger has. If it's just a matter of taking your time and following the procedure step-by-step and keeping track of which bolts go where, I can do that, but if it takes some experience and know how then I might have to take it to the dealer.
Hey man thats great, once you get the whole air box off it's not too bad from there, the only reason you need to take off the superchager is to get to the knock sensor, There is no WIS document for the harness and the only seals I have had to replace were the intake gaskets, the supercharger has a different type of gasket that you can re use, you may or may not have to replace the injector seal rings depending if you take the fuel rail off I don't but be caure because there is a guide nipple on the intake that can snap off, if you snap it off it's not a huge deal, if you take the throttle actuator off then you will have to replace that seal as well but you can get around that, anyway of you have had the complete airbox assem. off then you should be alright with the rest of the job if you feel comfortable, let me know what you decide or if you have any other questions
Thanks again, not familiar with e10 and e12 designation, searching the internet it looks like these are Torx sockets with an integral u-joint or ball joint? Do you know a site where to get these?
Sorry for all the questions.
I cleaned the connectors a few days ago so I'll see how long it lasts this is the third time. I really don't want to take so much of the engine apart if I can help it.
Yea thats what I use but an inverted torx socket with a swivel attachment works just fine Have you replaced both your cam magnets yet??? Ya if your not getting a check engine light you should be fine just make sure you check the harness where it goes into your M.E. Computer at the airbox if you ever see oil in there thats bad!! But i dont mind the questions Im just happy to help
I have seen some oil in the control module connector in the past but since I've put the isolating wires at the cam magnets that's stayed pretty clean. I haven't replaced the cam magnets but I might just do that. It's really only the oil that migrates down to the O2 sensor connector that's giving the check engine light (CEL). When I get the CEL I try not to drive the car until I can clean the connector because I believe its the heater in the O2sensor that fails.
I haven't looked that closely at the sensors, but one question comes to mind, can they be rotated so the wire connection is pointing up? Once I get my car back from the dealer for the vent hose recall I may just need to play for a while. I was just wondering if anyone has tried this.
Also instead of spending $60 on a couple of pieces of wire and four connectors, has anyone just cut the existing wires, and extend them by soldering some wires in place. I guess time is money, much easier and quicker just to snap in place the extensions.
Just pondering before starting the day, well goofing off at work if you want the truth.
Soldering is not usually a good idea in automotive environments. The adapters appear to be more than just wire extensions, they actually block the oil from coming up the wires via capillary action.
I have an issue guys and gals pease help.... I have a 2005 c230 with 37,000 and i noticed a slight oil leak at the cam mags and it looks like a chevy valve cover with built up dirty oil not much but like seeping maybe... but anyways my warranty is out in august so should i take my car in before then to have it checked out since it would be free? what do you think?
Absolutely dont wait. I had an O2 sensor issue that I took it in for under extended warranty in 2/08. They discovered a leak that they say caused the O2 sensor failure. After all said and done....$4k. My cost $100 deductible. I am now wondering if the same problem has arisen again, as it may have fouled out Wastegate solenoid P0243. Too late to claim warranty though. I have been driving it with CEL on for 3 mo., minor acceleration power loss, same gas mileage, 30mpg hwy, 2 cross country trips. Does not seem to be a major issue.
Just wanted to say Thank You to all on this post...
I was about to head back home (visiting my father at the moment) and decided to check my sensors, there was oil on both sides so I ordered the parts from the local dealer... $160 including $12 overnight charge. Changed the cam sensors, air filter, battery, and wipers in about 2 hours.
sounds good. Were you experiencing any symptoms (hesitation at quick accel, CEL codes) or just the oil? If you had the symptoms I described above, did changing the sensors solve your issue. I continue to drive with the CEL, slight hesitation issue. Looking at the forums there is a lot of conflicting info on degree of difficulty to diagnose and fix the P0243 problem.
I had a CEL but was pulling codes for misfire on cyls 1-4 and bank 1 rich... Taking it to the dealer when I get back home for the vent recall...
In my home town (way down in south Texas) I get great discounts on parts because the MB dealership knows my dad very well, so I figured I'd replace whatever I could at the time.
I just happened to check the connectors after reading this thread and found mine were leaking and I had a ~400 mile trip to make and didn't want to make it with leaking sensors just in case it got worse. Total for the parts + overnight to the dealership was about $160.
Took my 2003 C230K in to the dealer today because the check engine light came on. They called back and said that oil from either the oil level sender or the cam magnet sender had entered the harness and migrated to the O2 sender and ECM and recommended changing all of them including the harness, total cost $4100.00. WOW is all that nessesary? Im wondering if replacing the cam mag sensors and wire (that should stop the leak ) and cleaning the ECM connection would do it. The cars runs fine, same mpg, does that indicate that the ECM is fine or is it already damaged from the oil, also would both the O2 sensors need replacing. Going through the above posts, hey, lots of good info. Thanks for any and all help.
WHat amazes me is that Mercedes knows this is a problem, and the interconnect to block the oil flow from the sensor is insanely cheap, but they don't provide them, or even volunteer them during service.
4100 is ridiculous.
Anyhow, some have done ok by cleaning out the ECU and wiring harnesses with electrical cleaner and/or alcohol. I would manually check the ECU first to verify whether oil has gotten in there. Likely the O2 sensors need to be changed, though.
Thanks JC, Got the car back from the dealer yesterday, had them do nothing. Started by checking the cam mag sensors and found no oil, but on the safe side ordered new cam sensors,plug,o ring and isolation wires, $162 from a local mercedes shop. Next checked ECM and also found no oil, moved on to the O2 sensors and found oil on only the post cat sensor and not the pre cat one. Not sure if that sensor should be replaced or not, the cam mag parts should be in today, will install them tonight and probably run the car and see if CEL lights up or not. Very appreciative of all the great info on this forum and thread, a real time and money saver, but a little dissapointed in my MB dealer not sure if they were tring to hose me or not, will find out if the light comes on or not. Thanks again.
Finally got the cam magnet sensore and isolation wires installed, everything seemed fine, after about 25 miles the CEL comes on also alternator malfunction for only a minute or so, took the car to a independent mercedes garage and they checked the codes. They found a lot of electrical codes coming from the alt that is overcharging, so ordered a rebuilt alt. from them and installed( a little tricky but not bad), took it back and they scanned it again finding no fault codes and clearing the light and nothing wrong with the O2 sensors and told me to watch for the CEL the O2 sensor may fail later but also said i may have been lucky and caught it early enough. The guys at that shop were great offering tips and suggestions and knowledge about reoccuring problems that the dealer didnt want to devulge. Well hope this solves the problem. Thanks for all of the great info again.
This is good information, I got a CPO'd '05 C230K a few weeks ago with just over 50k miles on the odometer. I had a slow day at the office so I decided to wash it while I had my coffee outdoors at 79 degrees F. While wiping down the engine compartment I looked and saw this.
I pulled the cover off and took some close ups to send to my dealership guy.
He showed them to a service guy and I'm picking up a loaner tomorrow while they fix my cam sensors.
I really appreciate the information, Thanks to all who contribute.
I'm also getting that cold air intake hose nailed down where it belongs.
They call a vehicle in that condition a CPO? I'd be PISSED... and probably go to another dealership...
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