SL/R231: Oil Pressure Solenoid
Thread Starter
Junior Member
Joined: Sep 2018
Posts: 18
Likes: 3
2017 AMG SL 63 Polar White
Oil Pressure Solenoid
So I have been seeing a lot of videos on YouTube about the oil pressure solenoid in the M278 & M157 engines and that it can be disconnected to provide full oil pressure regardless of RPM. I unplugged mine, 2017 SL63, 29,000 miles, to see what would happen, and anecdotally I experienced the same benefits. These are not just shade tree mechanics, one rebuilt an engine and mentioned not connecting the solenoid. Seems that oil pressure regulation has to do with emissions. Anyone have an opinion?
Last edited by Box5232; Feb 22, 2026 at 09:13 AM.
Senior Member
Joined: Oct 2019
Posts: 293
Likes: 153
From: Nova Scotia, Canada
2019 SL450; 2023 M850i coupe
So I have been seeing a lot of videos on YouTube about the oil pressure solenoid in the M278 & M157 engines and that it can be disconnected to provide full oil pressure regardless of RPM. I unplugged mine, 2017 SL63, 29,000 miles, to see what would happen, and anecdotally I experienced the same benefits. These are not just shade tree mechanics, one rebuilt an engine and mentioned not connecting the solenoid. Seems that oil pressure regulation has to do with emissions. Anyone have an opinion?
https://mbworld.org/forums/e-class-w...et-nozzle.html
Crconsulting sums it up pretty well in post #18 of the thread.
Banned
Joined: Nov 2025
Posts: 477
Likes: 187
From: US
Mercedes SL R231
There are 4,427 posts on this topic in the thread Oil pump solenoids.
You will hear or read both sides of the story, but should ask what makes sense to you. All the claims about premature wear of chain guides seem ridiculous. For years, Mercedes instructed its dealerships to ignore the DTC P06DA00. And there are other manufacturers of two-stage oil pumps that confirm the PRIMARY purpose of the two-stage pump is to improve fleet gas mileage and maybe negligible emissions improvements. What makes no sense is to think that operating the oil pump normally and linearly somehow harms the engine, or that critical components would be intentionally built to fail under normal oil pressure (35-60 psi). With the solenoid enabled, there is a sudden shock to those components at 3500 rpm when the oil pressure doubles. That seems more destructive than a gradual pressure increase based on engine rpm.
It’s been shown that the Start/Stop feature of virtually all modern cars, again in order to improve gas consumption, is damaging and life-shortening to the engine. Just because Start/Stop was “engineered” for your engine, does disabling it harm the engine? No, it actually improves the survival of engines over many, many miles.
It is totally up to you what you do to your car, but do your research and decide for yourself. For me, I really like knowing that I have the best lubrication possible when I start and run my engine.
You will hear or read both sides of the story, but should ask what makes sense to you. All the claims about premature wear of chain guides seem ridiculous. For years, Mercedes instructed its dealerships to ignore the DTC P06DA00. And there are other manufacturers of two-stage oil pumps that confirm the PRIMARY purpose of the two-stage pump is to improve fleet gas mileage and maybe negligible emissions improvements. What makes no sense is to think that operating the oil pump normally and linearly somehow harms the engine, or that critical components would be intentionally built to fail under normal oil pressure (35-60 psi). With the solenoid enabled, there is a sudden shock to those components at 3500 rpm when the oil pressure doubles. That seems more destructive than a gradual pressure increase based on engine rpm.
It’s been shown that the Start/Stop feature of virtually all modern cars, again in order to improve gas consumption, is damaging and life-shortening to the engine. Just because Start/Stop was “engineered” for your engine, does disabling it harm the engine? No, it actually improves the survival of engines over many, many miles.
It is totally up to you what you do to your car, but do your research and decide for yourself. For me, I really like knowing that I have the best lubrication possible when I start and run my engine.
Thread Starter
Junior Member
Joined: Sep 2018
Posts: 18
Likes: 3
2017 AMG SL 63 Polar White
This topic is discussed at length in this thread:
https://mbworld.org/forums/e-class-w...et-nozzle.html
Crconsulting sums it up pretty well in post #18 of the thread.
https://mbworld.org/forums/e-class-w...et-nozzle.html
Crconsulting sums it up pretty well in post #18 of the thread.
Thread Starter
Junior Member
Joined: Sep 2018
Posts: 18
Likes: 3
2017 AMG SL 63 Polar White
There are 4,427 posts on this topic in the thread Oil pump solenoids.
You will hear or read both sides of the story, but should ask what makes sense to you. All the claims about premature wear of chain guides seem ridiculous. For years, Mercedes instructed its dealerships to ignore the DTC P06DA00. And there are other manufacturers of two-stage oil pumps that confirm the PRIMARY purpose of the two-stage pump is to improve fleet gas mileage and maybe negligible emissions improvements. What makes no sense is to think that operating the oil pump normally and linearly somehow harms the engine, or that critical components would be intentionally built to fail under normal oil pressure (35-60 psi). With the solenoid enabled, there is a sudden shock to those components at 3500 rpm when the oil pressure doubles. That seems more destructive than a gradual pressure increase based on engine rpm.
It’s been shown that the Start/Stop feature of virtually all modern cars, again in order to improve gas consumption, is damaging and life-shortening to the engine. Just because Start/Stop was “engineered” for your engine, does disabling it harm the engine? No, it actually improves the survival of engines over many, many miles.
It is totally up to you what you do to your car, but do your research and decide for yourself. For me, I really like knowing that I have the best lubrication possible when I start and run my engine.
You will hear or read both sides of the story, but should ask what makes sense to you. All the claims about premature wear of chain guides seem ridiculous. For years, Mercedes instructed its dealerships to ignore the DTC P06DA00. And there are other manufacturers of two-stage oil pumps that confirm the PRIMARY purpose of the two-stage pump is to improve fleet gas mileage and maybe negligible emissions improvements. What makes no sense is to think that operating the oil pump normally and linearly somehow harms the engine, or that critical components would be intentionally built to fail under normal oil pressure (35-60 psi). With the solenoid enabled, there is a sudden shock to those components at 3500 rpm when the oil pressure doubles. That seems more destructive than a gradual pressure increase based on engine rpm.
It’s been shown that the Start/Stop feature of virtually all modern cars, again in order to improve gas consumption, is damaging and life-shortening to the engine. Just because Start/Stop was “engineered” for your engine, does disabling it harm the engine? No, it actually improves the survival of engines over many, many miles.
It is totally up to you what you do to your car, but do your research and decide for yourself. For me, I really like knowing that I have the best lubrication possible when I start and run my engine.
Thread Starter
Junior Member
Joined: Sep 2018
Posts: 18
Likes: 3
2017 AMG SL 63 Polar White
Update: Anecdotally, I must say that the car runs smother. Upon starting there is the normal click, but it is just one and then the oil starts to circulate. When it runs it's quieter and more responsive. I like it better with the oil pressure solenoid unplugged.
MBWorld God!
Joined: Dec 2019
Posts: 32,222
Likes: 6,281
Glad to hear it, did you ended up leaving it as is or did you install a dummy solenoid to remove a stored code?
Trending Topics
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Junior Member
Joined: Sep 2018
Posts: 18
Likes: 3
2017 AMG SL 63 Polar White
MBWorld God!
Joined: Dec 2019
Posts: 32,222
Likes: 6,281
You either buy it from MB (exact same solenoid but just connect it outside) or just go through online sites for cheaper but takes a month or so to get here. There are links in the big thread.
Member
Joined: Mar 2026
Posts: 117
Likes: 50
I would not (and have not) spend the money for an Original MB solenoid. Just get the cheapest you can find on ebay or AliExpress. The dummy solenoid is sacrificial and only provides the impedance the ECU is looking for.
MBWorld God!
Joined: Dec 2019
Posts: 32,222
Likes: 6,281
Yup or buy from mbparts.mbusa.com for those who don't want to wait for the slow boat. Still way cheaper than the dealership, or perhaps even fcpeuro has it.
Thread Starter
Junior Member
Joined: Sep 2018
Posts: 18
Likes: 3
2017 AMG SL 63 Polar White
Thanks for the info. I've seen on other things where a resistor is just that, but if it's just as simple as buying another solenoid that's easy. Rock auto has them cheap and ebay even cheaper, and since it is not actually going into the engine, ebay here I come. I appreciate the information.
Member
Joined: Mar 2026
Posts: 117
Likes: 50
Part number 2781800315.
$55 on RockAuto (plus shipping) and about half that on AliExpress. (I would never try to save a couple of dollars on parts if I was really going to install this on the oil pump. The labor costs are too high to not use Genuine or OE parts.). Even Amazon has them for about $32. Again, these aftermarket solenoids are only to provide the impedance to keep the DTC from triggering.
$55 on RockAuto (plus shipping) and about half that on AliExpress. (I would never try to save a couple of dollars on parts if I was really going to install this on the oil pump. The labor costs are too high to not use Genuine or OE parts.). Even Amazon has them for about $32. Again, these aftermarket solenoids are only to provide the impedance to keep the DTC from triggering.
MBWorld God!
Joined: Dec 2019
Posts: 32,222
Likes: 6,281
Thanks for the info. I've seen on other things where a resistor is just that, but if it's just as simple as buying another solenoid that's easy. Rock auto has them cheap and ebay even cheaper, and since it is not actually going into the engine, ebay here I come. I appreciate the information.
Thread Starter
Junior Member
Joined: Sep 2018
Posts: 18
Likes: 3
2017 AMG SL 63 Polar White
MBWorld God!
Joined: Dec 2019
Posts: 32,222
Likes: 6,281
