JettaRed

iTrader: (1)

That upper pressure release valve is set to 4 bar. @S-Prihadi early measurements show that max oil pressure, with or without the solenoid connected, is ~60 psi (or 4 bar). My own tests with a mechanical external oil pressure gauge (as instructed in the WIS) only reached 50 psi at 4000 rpm. The pressure increase appeared to be linear with the engine speed. I think there is a "soft" rev limiter when in Park and I could only get to 4000 rpm. I have not tried measuring the pressure while driving. But, the point is disconnecting the solenoid does NOT cause excessive oil pressure.

JettaRed

iTrader: (1)

I think we are in agreement. My lengthly first comment today was about the posting that @kenneyd shared that the bestest mechanic shop is all of the western hemisphere said not to disconnect.

(By the way, I read your posts.)

ImolaSix

The theory is that the ECU energizes the solenoid upon cold start to limit pressure and shut off the oil squirters. This allows the piston to heat up much faster which helps with fuel atomization and better for efficiency. The German guys are saying that disabling this valve will keep the piston significantly colder during cold start and this will cause the atomized fuel coming out of the DI injector to condense on the cold piston and leak down the cylinder walls and into the oil. I personally don't see this being an issue unless someone wants to run 15,000 mile oil changes. DI engines have a tendency to dilute oil regardless so as long as your OCI are reasonable this shouldn't be and issue. There was a guy in the fb comment thread that said he will be running a blackstone oil analysis to see how much fuel dilution there is.

It's mentioned in the MB info page for the solenoid. Squirters are off for piston heating. then they are turned on to splash oil on hot pistons to heat up oil faster.

CaliBenzDriver

A random schmuck goes to a top shop in Germany to report a clerk said: DON'T DO IT !

Tassos and even myself said the same thing.

We live in the Nike country... "Just do it!"

I agree, cancelling chaos is not for everyone.

Rickman30

I have much respect for several on here like yourself and @S-Prihadi . He does a lot of great ground work, and many of his conclusions are proper. Sometimes we can over think this stuff when most of the time it's simple and physics can't be re-invented or changed.

The oil pressure measured depends on the quality and calibration of the gauge. Not knocking yours, but in my experience I've seen Snapon gauges vary as much as 10 psi brand new. That, coupled with different oil viscosity, the more miles oil has the lower the viscosity, plus ambient temps, it all plays a part in having a difference in oil pressures.

All oil pumps are linear, because they are mechanically driven by the engine. The pressure relief will also vary, albeit not by but a couple psi. mileage, region, and oil change intervals, spring tension of the pressure relief valve, they play a roll in observed pressures. It's why there is a test for the pressure spring to ensure it remains in the optimal range so pressure is not compromised. I wouldn't worry too much unless your gauge is showing below Xentry oil pressure test parameters, even then I'd acquire a precision gauge and retest. I'm reading in Xentry max pressure should be between 50 and 70 psi.

Also, I think you hit the nail on the head, many somehow think unplugging creates more oil pressure, it's not physically possible. The pump is what creates the pressure, the solenoid is on a port from the main pump gear, it diverts some of that pressure to the oil pan, when it closes pump pressure is resumed.

Rickman30

That was what fired me up too.

juanmor40

I was reading Mathias' response carefully waiting for his supporting material until I read "Don't suffer wannabe experts". Done!!!.

I have met quite a few of those in my career. Perhaps I used to be one in my youth, thinking I knew it all, but having the opportunity to study, work or interact with highly qualified individuals, I learned to listen and always support my views with my own data, or well-researched literature. Of course, you also learn to live with your own decisions.

Rickman30

The head tech at my dealer said the same thing, but was speechless when I gave him a copy of the Xentry instruction for that code saying don't fix if nonessential part circuit opened.

CaliBenzDriver

Now that we know where these valves are, individuals can accomodate need for personal testing.

Wire an inline switch to enable/disable solenoid on-demand.

This could be interesting to see how confused the ECU/TCU adaptations can get.

I think even the stock system strugles with that mixup when solenoid gets activated for cooling.

The positive transformation we get is not from giving VVT more oil.
It is from ECU learning the stable timings of the improved engine:

1. sealed piston rings
2. balanced cylinder work
3. tight tensioners
4. cleaner lambda
5. lubed HPFP roller
6. strong VVT B1i.

I don't think these ECU are ready to go back and forth, quite the opposite. The ECU snappiness is hinged upon regularity.

kenneyd

There are several people in this thread that have run Blackstone oil analysis already.
That's the document I've been referring to numerous times in this post. Describes the scenario of cold start where it will start for a short period of time on low pressure in order to let the Pistons build some heat, and then, while still cold, it engages high pressure in order to warm the oil faster.
The reasoning in the document says nothing about fuel atomization or condensation, it says the reason is it will warm the oil up to temperature faster. 100° piston versus a 200° piston is not going to affect the fuel in any way shape or form.

This document description alone puts the bed many of the concerns people have had, such as will running high pressure in cold climates. Well, according to this document, the intended design runs high pressure shortly after a cold start.

​​​​​​
​​​The biggest change I've noticed is the oil does heat up much faster with solenoid unplugged. So, pistons Do have a significant effect on the oil.(Also meaning, the oil has a significant cooling effect on the Pistons, which is one of the biggest reasons we're doing this mod)
I'd have to go back and look at testing videos people have made, but my assumption is the Mercedes piston heating programming described here is really only for very cold oil to get it up to something say around 50 Fahrenheit... And it reverts back to closed after that
Because with the solenoid unplugged, my oil gets up to 175 in like 10 minutes or less while with it plugged in, it would basically stop at 125 and plateau unless I drove more aggressively.

ImolaSix

I agree with you. The part about the condensation was me interpreting what that German shop guy said in that fb message.

Anyways, I think people get too hung up on that shop being from Germany as if their word means anything more because MB are made there. If that fb post was from some random small American tuning shop no one would bat an eye.

billvp218

that seems strange ... my car's oil temp gets up to 80*C (176*F) in about 10 minutes of normal easy driving in the winter at temps near freezing

I never drive it hard before it gets to the proper temp, so I watch the value

TomZVB

Comment removed - late to the party.

WRC-LVR

@rickman that posted pdf has no info about the piston oil squirters or the pressure they need to operate it is a disclaimer about the code for the solenoid failure or in this case what pops up if you disconnect it...Is there a solenoid to open the oil squirters only? That is what I am getting from your post?

Highly doubtful MB would do that. Oil squirters are there to cool the pistons down on an already hot turbo'd engine.

OTH if you meant that the oil squirters provide full oiling at the 40 psi listed maybe sure but i still dont beleive in 0w-20 oil lubricates better or that the thin layer of thin oil protects better than say 5w-40 .its only there to help reduce operating friction and help with mpg mandates..so you would def want to do the oil solenoid disable to get full pressure at all times and use 5w-40 for sure

Agreed that the manufacturers seem to design these to fail from so many parts and mechanisms...they want you to buy another one in 3 years as the warranty expires and junk the present one. Dont event get me started on pushing incomplete "tech " out the door that doesnt even work and requires multiple updates or fixes that take months or even a year to get.

Not just about MB...All manu do it ...Toyota has the same issues...AND they use the same type of oil solenoid. I just gotta figure out if I can disable that one in my 2022 Highlander Platinum AWD V6 now

S-Prihadi

.
On the subject of OIL TEMPERATURE, you guys with M157.9xx are blessed....... to have a REAL oil temperature sensor and not a calculated one like M278 or M276.
I kept reading oil temperature values mentioned and I looked at the ECM wiring diagram and wow !!! No bul-shiet !!!

B40 is an oil level sensor and oil temperature sensor. I do not know the OIL QUALITY capability of it.
LIN based data communication, sharing LIN line with alternator LIN.











Only M157 and M152 get this beautiful multi-sensor. I am drooling..... I don't mind if this can be factory option on my engine for US$500 or US$750 if oil pressure sensor included too and both data to be displayed at IC.
Hence I can get dual data with the Banks Gauge system as back-up or cross verification.






Not cheap too..........










Hhhmmmm... look so pretty...

Rickman30

Piston cooling was originally designed to mitigate detonation, or pre-ignition from leaning the mixture to gain more HP and torque it the peak of the power band on race car engines. Manufactures now use it on NA and turbo engines for the same reason. They later started added oil pressure controls to reduce cold start enrichment times. On engines with variable and two stage oil pump systems the oil system is used to control those temps as a cold engine requires more fuel when cold then leaner when closed loop is achieved. At which point PCM takes over and uses sensors throughout engine to achieve stoichiometric efficiency in each cylinder, ambient air temp, air volume, engine temp, lambda at exhaust even coolant temp dictates if more or less fuel is needed. The operating pressure for the cooling nozzles or piston oil squirters, is normally above 35 to 40 psi in a normal engine but can be changed by swapping the pressure spring either way, MB does not give an exact valve opening pressure for them just the values at 600, 2500, and 3500 rpm, only that they should work when oil solenoid is closed and full pressure is achieved, this can be found in Xentry in oil pressure testing general description on the M276 NA version. I've not investigated the turbski version. The valve closing "piston oil squirters" is much like the pressure relief valve in the oil pump, a check ball and spring.

They do not use oil pressure in the PCM strategy, as this would require far more processing power and software for every conceivable scenario to not disturb the EPA fuel consumption boundaries. I'm paraphrasing now.

Also, there is no way unplugging will destroy the engine. Open, it reduces oil pressure, closed, full oil pressure is resumed. If the engine dies because of this solenoid, it is because it was stuck open and not allowing enough oil pressure to open piston cooling jets, "piston oil squirters" and high RPM superheated pistons induced pre-ignition resulting in destroyed pistons beginning with the crown of the piston as it is the thinnest part nearest the valves. Detonation of incoming fuel by the superheated pistons will also be observed before catastrophic failure results. This is my interpretation of the information on catastrophic engine failures found most anywhere.

If any one has been to races and observed glowing red headers while running hard, that is the exaggerated heating in the cylinders I speak, granted, unless tuned ours will never do that, but the principle is the same, lean the mix to make more heat equals more torque. These engines are leaned out like this due to the demand for more horsepower by buyers but still meet the EPA mandates.

On oil, Manufactures build an engine around a goal, the oil specified to meet certain EPA boundaries adds to the equation for the best MPG, not longevity. Lower viscosity oils lube all the bearings faster than thicker oils, thicker oils also can reduce HP peaks as shown on Dyno runs for race engines. Engine builders test each weight till a happy medium of quick lubrication and maintaining steady oil pressure throughout the RPM range. Street cars are a lot more forgiving in viscosities used. But if you have a tune or race your car, oil analysis and tunners recommendations are more important.

A few manufactures began using "Planned Obsolescence" in the 80s, by the 90s all of them adopted the practice. Profit over integrity.

Years of working on older engines, and race engine/ transmission builders in the family, pretty much helped form these opinion.

JettaRed

iTrader: (1)

Just make sure the default failsafe position is for full oil pressure and not restricted oil pressure.

Lotty

I don't find a dealer to check this Every1 told me they need special tool and they don't have it. I got all part numbers from dealer to check my oil pressure. Very expensive **** for my car
I hope i got a full oil pressure.

Rickman30

I got the same answer for my coolant when I asked if it needed changing. "Oh that takes a special tool we don't have" I said you mean the entire shop no one has a $2 coolant tester, and Snapon comes here every week. "Snapon doesn't come here" I said "Your Snapon dealer is a friend of mine, I happen to know what day and approximate time he stops here, we had lunch just across the street two weeks ago"

JettaRed

iTrader: (1)

They were probably referring to not having a $50 vacuum coolant purge and fill kit. 🙄

Rickman30

No, the conversation was only about testing the coolant. Even if they wanted test strips or a refractor those are available at parts hoses here too. Funny thing is, MB provides all the special tooling for every maintenance and repair they require, the tech only needs to posses basic hand tools.

JettaRed

iTrader: (1)

We know that the Mercedes solenoid defaults to normal pressure when not energized. If everyone told you they need a special tool, then maybe they shouldn't be working on Mercedes.

The process is simple.

1. Connect an external oil pressure gauge and described in the WIS instructions.
2. With the solenoid connected, read the oil pressure at 2000 rpm. It should not exceed 2 bar at any engine speed up to 3500 rpm. Above 3500 rpm, the pressure should increase to a maximum of 4 bar.
3. With the solenoid disconnected, read the oil pressure at 2000rpm. The pressure should exceed 2 bar. If it doesn't, increase the engine speed up to, but not at or above 3500 rpm. The pressure should exceed 2 bar. If necessary, increase the speed above 3500 rpm and take note of any jump in oil pressure.

Make note of the differences between connected and disconnected. The disconnected state is the default state. The attached document instructs how to test the oil pressure with the solenoid connected.

Lotty

Again, what is default/normal pressure = max 4bar/3.5bar or 2bar?

here the test the oil pressure document for M133

JettaRed

iTrader: (1)

Well, that's rather interesting for your car. It looks like the rise in oil pressure is linear for the M133 engine. Did we determine that you had a two-stage oil pump?

Lotty

Idk i'm confused