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This mod was brought to my attention by @W205C43PFL. Some M157 owners have done this mod and reported good results, so I decided to try it. From what I gathered from the threads I read the oil pump has 2 modes, actuated by a solenoid. The solenoid is normally open with the pump in high pressure mode and closed to low pressure mode during idle and low engine load (I.e. cruising). Unplugging it leaves the pump in high pressure more only which allows for increased oil reaching the piston squirters and flowing around the engine etc. allowing quicker warm up times and better oil flow for longevity.
Oil temps climbed much more quickly; car reached oil operating temp way faster and stabilized around 200°F when before the oil would sit around 190 but would randomly climb to 220 and drop back to 180 multiple times while cruising. No codes yet but only have done 1 drive with it unplugged, however people on the thread reported that they have had 0 CEL but the car does throw a hidden code.
Haven’t noticed any performance improvements like some reported in the thread but again I’ve only driven it once, however the oil warming up quicker and stabilizing where it did made the mod worth it, along with the increased oil flow.
The plug is in a very difficult location to access, sandwiched between the IC and the engine block on the passenger side right next to the crank pulley. I used a right angle hook tool to pry the silver clip open, push down on the connector and pull it loose. You’ll need to use a phone camera next to the power steering motor looking in in order to see what you’re doing and you must access from below by removing the front skid plate. I posted a photo and there are more photos in the main thread posted below.
I did read through the testing thread performed by other members and it checks out. I do think this mod will benefit our engines in the long run, however there is risk attached as with every mod although I believe this mod doesn’t have much. More oil flow is never a bad thing.
Photo of location. Very hard to see and fit your tool in but it is possible.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by Ginco
This mod was brought to my attention by @W205C43PFL. Some M157 owners have done this mod and reported good results, so I decided to try it. From what I gathered from the threads I read the oil pump has 2 modes, actuated by a solenoid. The solenoid is normally open with the pump in high pressure mode and closed to low pressure mode during idle and low engine load (I.e. cruising). Unplugging it leaves the pump in high pressure more only which allows for increased oil reaching the piston squirters and flowing around the engine etc. allowing quicker warm up times and better oil flow for longevity.
Oil temps climbed much more quickly; car reached oil operating temp way faster and stabilized around 200°F when before the oil would sit around 190 but would randomly climb to 220 and drop back to 180 multiple times while cruising. No codes yet but only have done 1 drive with it unplugged, however people on the thread reported that they have had 0 CEL but the car does throw a hidden code.
Haven’t noticed any performance improvements like some reported in the thread but again I’ve only driven it once, however the oil warming up quicker and stabilizing where it did made the mod worth it, along with the increased oil flow.
The plug is in a very difficult location to access, sandwiched between the IC and the engine block on the passenger side right next to the crank pulley. I used a right angle hook tool to pry the silver clip open, push down on the connector and pull it loose. You’ll need to use a phone camera next to the power steering motor looking in in order to see what you’re doing and you must access from below by removing the front skid plate. I posted a photo and there are more photos in the main thread posted below.
I did read through the testing thread performed by other members and it checks out. I do think this mod will benefit our engines in the long run, however there is risk attached as with every mod although I believe this mod doesn’t have much. More oil flow is never a bad thing.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Never had a chance to get to this but now back home planning to tackle this one soon, any other C 43 owners unplugged it yet and enjoyed the benefits?
I wonder if there is anyway to do this from the top, I have a bad back.
Forum member JettaRed mentioned: "Again, however, on the M276 engine, the wiring harness attaches to the internal wire to the solenoid through the block on the front of the engine to the right side of the crank pulley."
As Roy said to his maker:
Unplugged this morning. I will keep a close eye to see if anything feels like it has improved. I have 109,763 miles on the old girl...and as she's the daily driver, I want to maximize her lifespan.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by SizzlCheez7
As Roy said to his maker:
Unplugged this morning. I will keep a close eye to see if anything feels like it has improved. I have 109,763 miles on the old girl...and as she's the daily driver, I want to maximize her lifespan.
Wow glad to hear that you have all those smiles per miles.
I currently have my car up on ramps with both belly pans off.
While I can BARELY see the back of what I suspect is this connector, I have no idea how you're supposed to disconnect it without removing the lower intake charge pipes, and possibly the intercooler.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by TwoC400s
I currently have my car up on ramps with both belly pans off.
While I can BARELY see the back of what I suspect is this connector, I have no idea how you're supposed to disconnect it without removing the lower intake charge pipes, and possibly the intercooler.
This is what you are looking at: https://mbworld.org/forums/e-class-w...76-sensor.html
It was very difficult for me to get to, I reached from the top (doable) with longer hands (failed because my arm with too short). It took me multiple weeks to finally got it off (but that is because my technique was wrong). Forum member JettaRed did it from the top if I recalled correctly.
I'm not sure if the C400 is configured just differently enough, or what, but there's ZERO chance I'm getting it from the top, it's directly under the tiny space between the IC coolant reservoir and the throttle body motor.
I'm pretty sure I'll be able to get it from the bottom, but will need an extra long 90deg pick (ordered) and a very long set of articulated needle nose pliers (I already have a set).
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by TwoC400s
I'm not sure if the C400 is configured just differently enough, or what, but there's ZERO chance I'm getting it from the top, it's directly under the tiny space between the IC coolant reservoir and the throttle body motor.
I'm pretty sure I'll be able to get it from the bottom, but will need an extra long 90deg pick (ordered) and a very long set of articulated needle nose pliers (I already have a set).
It should be the same, the C 43 and C 450 is just a horsepower bumped M276 compared to the C 400. Then there is the transmission differences which shouldn't matter.
I felt the connector when I tuck my arm way down there but it was still too short to unplug it. I do recommend going from the bottom as you decided for that reason.
Both the C 43 and the C 400 seems to have 4MATIC so that too is the same. With the transfer case and all that good stuff.
Best of luck : ) on getting it with the new tools you ordered, hopefully that does the truck.
Man, what a PAIN. The extra long pick set from Gearwrench made getting to the clip quite easy, but using my long needle nose pliers to thread the zip ties to hold the plug/harness in place and out of the way was a PAIN.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by TwoC400s
Got It!
Man, what a PAIN. The extra long pick set from Gearwrench made getting to the clip quite easy, but using my long needle nose pliers to thread the zip ties to hold the plug/harness in place and out of the way was a PAIN.
Took the passenger side air duct off and shoved my arm in to feel out the solenoid connector on the c450.. hand would reach the waterpump and won't go any lower, arm gets stuck. Will try from the bottom soon, surprised members on here got it from the top(lucky lol)
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by Manny_c450
Took the passenger side air duct off and shoved my arm in to feel out the solenoid connector on the c450.. hand would reach the waterpump and won't go any lower, arm gets stuck. Will try from the bottom soon, surprised members on here got it from the top(lucky lol)
Yup forum member JettaRed got it from the top : ) but it wasn't the 43 or C 450. His car might not be 4MATIC too so that might be another factor.
Ya, for our cars it is easier from the bottom, best of luck on it : ) You will love the benefits!
I took the route of going to my local (subaru-centric) indy shop for handling the "procedure". They put the old girl up on the lift, removed the pans, and used the long picks to remove the plug. Not even 5 minutes. Because I brought them donuts and I happened to schedule the first slot of a (slow) morning for the shop - they didn't charge me for their effort. We used a scan tool and verified the hidden code P06DA00. They remarked that rarely do any customers come to them for "adding" hidden engine trip codes to their car! Lol. I explained to them about the theory behind the cheap mod beforehand, and the benefits...they agreed that it couldn't be remotely harmful to run at "regular" oil pressure full time.
I also contacted a very reputable (and moderately more expensive) indy shop that specializes on working/repairing exclusively German makes. After a brief explanation, they asked me to forward the links (shared on this forum) pertaining to the switch mod. Subsequently they then forwarded the links onto their inhouse Master Tech / Guru of Mercedes after digesting themselves. The indy came back within two hours to me, in full agreement that this mod has no apparent downside, but smartly they said they would have me sign a document stipulating that they would not be held liable for executing the mod on my behalf.
I have noticed that the oil temps rise much faster every morning, but I cannot notice any real world difference in acceleration, torque improvement, or brake pedal feel improving - despite a couple weeks and about 500+ miles. Maybe our normally aspirated cousins have those real world gains, but I kind of think they are just placebo effects. However, the piece of mind that my car has "normal" oil pressure full time is worth it. Too bad the smart MB engineers were forced by the accountants/management, who were forced in turn by the politicians to design unnecessary complexity into this platform, attempting to squeeze barely perceptible fuel economy gains - all at the risk of oil starvation, at least for us long term owners. I suppose it's a win-win situation if you want to sell more cars though
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Originally Posted by SizzlCheez7
I took the route of going to my local (subaru-centric) indy shop for handling the "procedure". They put the old girl up on the lift, removed the pans, and used the long picks to remove the plug. Not even 5 minutes. Because I brought them donuts and I happened to schedule the first slot of a (slow) morning for the shop - they didn't charge me for their effort. We used a scan tool and verified the hidden code P06DA00. They remarked that rarely do any customers come to them for "adding" hidden engine trip codes to their car! Lol. I explained to them about the theory behind the cheap mod beforehand, and the benefits...they agreed that it couldn't be remotely harmful to run at "regular" oil pressure full time.
I also contacted a very reputable (and moderately more expensive) indy shop that specializes on working/repairing exclusively German makes. After a brief explanation, they asked me to forward the links (shared on this forum) pertaining to the switch mod. Subsequently they then forwarded the links onto their inhouse Master Tech / Guru of Mercedes after digesting themselves. The indy came back within two hours to me, in full agreement that this mod has no apparent downside, but smartly they said they would have me sign a document stipulating that they would not be held liable for executing the mod on my behalf.
I have noticed that the oil temps rise much faster every morning, but I cannot notice any real world difference in acceleration, torque improvement, or brake pedal feel improving - despite a couple weeks and about 500+ miles. Maybe our normally aspirated cousins have those real world gains, but I kind of think they are just placebo effects. However, the piece of mind that my car has "normal" oil pressure full time is worth it. Too bad the smart MB engineers were forced by the accountants/management, who were forced in turn by the politicians to design unnecessary complexity into this platform, attempting to squeeze barely perceptible fuel economy gains - all at the risk of oil starvation, at least for us long term owners. I suppose it's a win-win situation if you want to sell more cars though
Haha, that is a good one : ) (the bolded part) When shops around me refused to help (as I got lazy... and didn't want to do it myself) I realized the saying was right, when I need a job done right... i'll do it myself and glad I did enjoying only benefits. With the help of forum members on the big thread, I was able to get it in... 2 weeks... finally.
Weird you don't notice any improvement in the driveability of the vehicle, I have a 2017 C 43 and instantly noticed the reduced throttle hesitation (or even turbo lag) the car really just goes when I suddenly floor the gas pedal it doesn't take like 2 seconds anymore to decide when it wants to shift down a gear (guess the 2 seconds is the time needed to switch from low to high/normal pressure mode).
My family relative that rode with me the other day asked me why I suddenly accelerated so rapidly at a stop, I told them I was just driving the usual way lol.
PFL205.064 with M276.823 (Oil pump solenoid defeated)
Forgot to ask, did you get your guy to plug/seal/tape/cap both sides of the connector? Basically to prevent water and/or dirt to get into the live connection? If so, what did they and you use?
12-27-2023, 02:27 AM
