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Normally, I wouldn't dismiss your claims of "suspicious timing" but I drove the car after the fact and it ran perfect before it **** the bed, so to speak. He had no reason to intentionally "sabotage" anything nor do I think he would risk his 20 yr business with stellar reviews for both of his locations for 1 car. It's honestly "just my luck". My 911 did the same thing several years earlier ("watch out for the water pump, the bearings tend to go between 50-60k", 2 weeks later @ 54k miles spins the bearings in the pump, a Tahoe did the same with the transmission.) All different shops, 20 years apart in timing. Again, just my luck. My current service guy did clean the plug/harness to a degree, before he put it back together, but it only takes 1 tiny little drop to complete a circuit and ground everything out. Like the old saying goes- "If if's and but's were candy and nuts, we'd all have a Merry Christmas", fact of the matter is these are 6 figure cars, with what is touted as some of the best, most precision engineering in the world, technologically advanced, high performance, and the upper echelon of luxury vehicles and they have an incredibly STUPID flaw that can destroy them and typically isn't caught until it's way too late to remedy. Honestly makes me rethink my impression of the brand. Just my opinion though.
I didn't necessarily mean fishy as sabotage but bad luck and perhaps related. I definitely had five or six of the eight sensors leaking into the harness all the way the the ecu before a thorough cleaning. I wondered if I would also have to try the warranty like you. I fixed it all for the cost of the sensors from fcp and a few cans of crc electronics cleaner.
Were all of the codes from the unplugging from the cleaning process cleared before new codes read? Are you sure that all parts have to be replaced at this point? I see you sent it off and say it runs fine. Does it only run fine sometimes?
Why not just clean and replace the leaking parts? Warranty company will have an issue if it runs fine...imo. If they give you trouble don't fret if the car still runs fine.
I too think it sucks when these expensive cars have leaky sensors. fact is that all the plastic used these days does not last on a hot engine. All of these sensors leak where plastic and metal interface and the materials expand and contract at different rates. The only thing done could have been to create the better harness protection from the leaks that inevitably happen due to the aforementioned rates of expansion as well as crankcase pressure.
Is this a fix it and be done for life kind of thing or is this an issue that is just going to recur in the future? Any idea how long the replacement sensors should last before it could start leaking again?
Seems like this is TBD, but the general problem is that the plastic expand and contract at different rates. Add oil under some positive pressure and it's easy to get oil going through the plastic, following the metal to the wire behind.
Could the mfg make sensor 100% leak proof? Absolutely, but that would cost more and likely not worth it.
Compared to the plastic fluid lines,this is a small(ish) problem and something we will add to the list of "check every now and then".
And every time to drive your car, be happy it's not a "hot vee" engine - that whole construct; super hot turbos, small space, covered by decorative covers, is almost the best possible path to make plastic fluid lines brittle and break fast. Which is exactly what you are seeing on MB, BMW, Porsche, and Audi engines....
I didn't necessarily mean fishy as sabotage but bad luck and perhaps related. I definitely had five or six of the eight sensors leaking into the harness all the way the the ecu before a thorough cleaning. I wondered if I would also have to try the warranty like you. I fixed it all for the cost of the sensors from fcp and a few cans of crc electronics cleaner.
Were all of the codes from the unplugging from the cleaning process cleared before new codes read? Are you sure that all parts have to be replaced at this point? I see you sent it off and say it runs fine. Does it only run fine sometimes?
Why not just clean and replace the leaking parts? Warranty company will have an issue if it runs fine...imo. If they give you trouble don't fret if the car still runs fine.
I too think it sucks when these expensive cars have leaky sensors. fact is that all the plastic used these days does not last on a hot engine. All of these sensors leak where plastic and metal interface and the materials expand and contract at different rates. The only thing done could have been to create the better harness protection from the leaks that inevitably happen due to the aforementioned rates of expansion as well as crankcase pressure.
did you spray crc directly into the ecu socket? I’ve been a bit apprehensive to soak it in crc. I have using vacuum with paper towel in between to act as catch so I can see how much oil is being sucked out.
Anyone here have the Fidelity Platinum extended warranty?
Yes, and used it through a Mercedes dealership and they handled everything. It was not for this issue though. (Fidelity)
Per CRC, yes you can spray directly into the ecu socket and all sockets in the harness, all over. Hold so socket faces down and spray runs off as you spray. I, like the poster above have used this cleaner on everything. Wait for everything to dry before energizing. Most people don't realize that electronics can get wet, but that you just have to dry them properly before energizing.
Last edited by Baltistyle; 06-01-2022 at 10:26 PM.
Is there a TSB on this? If it's this common, MB has to know about it. Also at what mileage are people seeing this?
No TSB to speak of, just seems to be a problem that Mercedes is willing to "live" with and pass the headache along to owners. Mine is a 16 with 63k and my tech found it when the car went in for an oil change. The crazy part is, this car was previously serviced at the dealer for every oil change/service interval and it was never even looked for. Most dealer service departments aren't even looking for this issue typically until it's too late from what I am hearing it seems. And they took the car back in on trade, serviced it, "inspected" it and sold it with this issue. Hind sight being 20/20- unplug the harness from the ECU on any M157/M278 before you buy it. Hell, I think at this point I'd do it on any Mercedes I'd purchase (if I ever do again after this one).
Ok, finally heard back from everybody, we're all on the same page and authorization to work has been given. It's not a perfect situation, but it's better than being stuck holding the entire bag. So the warranty company has company has come back after inspecting and has decided to pay for certain items, but not everything. Easy Care's (the warranty company) "loophole" as you could say, is that "the warranty fixes parts that have failed and no longer perform their intended duty". So, CPS sensors, magnets, Oil Pressure solenoid and the labor involved they are covering- about $4000 worth of work. Even though, according to Mercedes Benz, the harness and ECU should be replaced because they are contaminated, the warranty will NOT replace, because they are still in "working order". Harness still transmits power from one end to the other, ECU still turns on and functions. Now, my tech, will not perform the work without at MINIMUM replacing the entire wiring harness. There is still oil in it, and no matter how good you clean it, there will be oil still within the bundle of wires, and guess what- it will continue to draw up into the ECU. Ultimately causing failure, yet again. So, I am coming out of pocket for the harness to be replaced and the additional labor, etc. Now while the engine is out of the car, we are going to go ahead and replace all of the cooling hose leads (search the threads, these stupid plastic things break all the damn time too) and a few other things that are just easier to deal with and reduce the labor costs because the engine is out and available. Basically taking care of some preventative maintenance, which to me is definitely the smart thing to do.
So in conclusion, a "bumper to bumper, unlimited warranty" may not be all it's cracked up to be, and just like everything else these days, they look for any reason to not pay out. They replace failed parts, they DO NOT return a car per factory specifications. Again, it could've been a lot worse and I could be looking at $8000 out of pocket versus about $3500, and sadly, I'm fine with the $3500. Now I have the hard decision of whether or not I keep the car after he repair work is done. It's going back together with Mercedes Benz factory parts, it will fail again, it's inevitable. This was a "bucket list" car for me, now I've had it, it may be time to move on to something else and get out of it while the market is still good.
Thats good news. How much did you pay for the extended warranty? It sounds like it may have paid for itself by now and you still have the warranty in the future for other repairs if needed. I think you'll come out ahead in the long run
Is there a TSB on this? If it's this common, MB has to know about it. Also at what mileage are people seeing this?
There are pigtails (can’t remember if I read someone mentioning this here) that can be attached to the sensors that apparently stops the wicking. This is the way that Mercedes decided to deal with it. Unfortunately sensors are replacement items, like turbo coolant lines and air intakes. Takes under two minutes to check now that you know.
Last edited by Baltistyle; 06-02-2022 at 06:59 PM.
On M157, the bottom screw of the left solenoid is in the lower position compares to M278 make it unable to get to. I removed the oil filter and the 2 oil cooler pipes (?) and still don't have enough clearance to remove that bottom screw. I get stuck here. Need help please. I can't seem to find a video for M157. The passenger side is the same for both M278 & M157. The driver side on M157 is much more difficult.
On M157, the bottom screw of the left solenoid is in the lower position compares to M278 make it unable to get to. I removed the oil filter and the 2 oil cooler pipes (?) and still don't have enough clearance to remove that bottom screw. I get stuck here. Need help please. I can't seem to find a video for M157. The passenger side is the same for both M278 & M157. The driver side on M157 is much more difficult.
if it’s the oil pressure solenoid you’re going after, the engine has to come out or the entire subframe has to be dropped if I understand correctly. This most certainly does not fall under the “superior German engineering” we are used to.
Thats good news. How much did you pay for the extended warranty? It sounds like it may have paid for itself by now and you still have the warranty in the future for other repairs if needed. I think you'll come out ahead in the long run
Yes, this pretty much covers the cost of the warranty. It’s just a pain to deal with and it’s a little bitter considering my previous Mercedes never had a single issue, 150k on the odometer and still going strong when I sold it. And I know it’s 2 completely different animals, but still, I just don’t want to feel like I paid a lot of money for a high end vehicle that is constantly in the shop- warranty or not. That’s just not my idea of luxury, if I wanted that, I would’ve just bought a Z06. Lol
if it’s the oil pressure solenoid you’re going after, the engine has to come out or the entire subframe has to be dropped if I understand correctly. This most certainly does not fall under the “superior German engineering” we are used to.
Really? wow! Has anyone get this done? The camshaft position sensor leaking is a much more common issue than the magnet solenoids leaking right?
Really? wow! Has anyone get this done? The camshaft position sensor leaking is a much more common issue than the magnet solenoids leaking right?
Yes correct, mine currently is all 4 of the camshaft sensors AND the oil pressure solenoid. So yes, I am currently having it done and yes, the engine is completely out of the car to do it. 😑 Here is a pic of the video my tech sent when he first discovered, you can literally see all the oil on the plug from the solenoid.
Mine are still very clean, no leak yet, I'm doing this for prevention. I got 4 camshaft position sensors and 3 solenoids done, get stuck at the 4th one.
Mine are still very clean, no leak yet, I'm doing this for prevention. I got 4 camshaft position sensors and 3 solenoids done, get stuck at the 4th one.
and this is the best way.
IMHO, First step for anyone in this situation with a wet sensor is to
1. check harness sockets. You will see if and how far oil traveled. Note wet stuff
2. clean the effected areas with electronics spray. (Have key far away, make sure nothing is energized, pull batteries if you’d like)
3. order new sensors for the areas you see contain a leak. (Vs sensors effected, they may just need clean but not replace)
4. Clean a lot more spraying everything that has an wet oil residue. Imo light oil will cook off if “breaks” in the chain of the fluid are made by cleaning all accessible areas. Every socket and pin, hole in sensor and socket, for redundancy. Do it again the next day since remaining oil will possibly wick and you can look at sensors
5. Put it back together in no time, except for some r and r on sensors
6. if it was and continues to drive well, just monitor it. If there was an issue, this might clear it up with replacement of bad sensors. Oil in a harness does not wick forever, and with new sensors does not continue and is way better than the initial wetness. I think I cleaned the ecu over three times over three days of driving.
If none of this worked, you’re only a few hundred in and now you can think about other harness or related motor out procedures.
I write this so that everyone does not panic while reading these threads. I’m a very learn as you go diy mechanic and this will not require engine out 99% of the time (or even less I’d bet) ymmv and good luck to op as this is a case where the warranty company covered as they normally do and the mechanic has their way.
Last edited by Baltistyle; 06-03-2022 at 06:39 AM.
The camshaft (cps sensors) are very easy to replace . Located visibly on top of the valve covers 4X . The magnets on the other hand look to be an issue on the driver side accessing . I'm looking into doing the magnets myself along with the oil pressure switch as mentioned above . @sunil517 Checking on the location of the oil pressure switch myself now .
I believe with the right tool I can get this done without removing the oil filter housing. Does anyone know where to get a set of super thin (low profile) ratchet wrench? Amazon has the super thin wrench set but they are open end style. I need the box end style or ratchet even better. Thanks.
According to Factory WIS Maintenance and repair, the engine doesn't have to come out to replace the magnet solenoid.
I believe with the right tool I can get this done without removing the oil filter housing. Does anyone know where to get a set of super thin (low profile) ratchet wrench? Amazon has the super thin wrench set but they are open end style. I need the box end style or ratchet even better. Thanks.
According to Factory WIS Maintenance and repair, the engine doesn't have to come out to replace the magnet solenoid.
05-28-2022, 02:44 AM
and a few cans of crc electronics cleaner.
