JettaRed

iTrader: (1)

No, I don't think that is what he is saying. I understood him to say that there is additional stress on the oil pump in extremely cold climates, but that it is also oil weight dependent. I know a lot of folks here like to use 5W-50, but I have always used Mobil 1 0W-40 and will continue to during winter months. I may change to 5W-50 during hot weather, but for now it will stay 0W-40.

He is also undecided, which he stated several times. It will be interesting if he continues to ponder this issue and makes a final decision.

BDC90

It also plays into the "don't beat the engine until correct oil temp achieved"

kenneyd

Speaking only to this point, I disagree on any negatives from cold starts based on Mercedes description of the system does say the high pressure (better labeled as normal pressure) is activated for cold starts...
there's is still a pressure relief valve that limits the pressure to a safe amount during it's highest pressure senarios, such as "cold honey" Alaska starts.

BDC90

Right, I forgot about that.

juanmor40

He needs to be cautious that someone disconnect the solenoid because of his advice, and the engine fails later for some other unrelated issue. You know, my engine failed because some person snizzed in the Artic.

Love it when he splits drivers into 20's and 50+'s. Where does he think the "pre existing wear" comes from? Low oil pressure for those driving like grandma below 3000 rpm? I am a bit on the fence why full oil pump behavior will wear oil faster. Oil wear faster because of high temperature, and fuel and soot pollution. I agree that those on cold climates to stick to 0W40, and 5W40 for moderate weather. I would have done so even in Toyotas, low for winter and higher for the rest of the year.

As sta@CaliBenzDriver , the mod is not for everyone, but those willing to do the due diligence, and make a conscious decision. I did my E, and will do my ML after new year.

wheatswake

Any thoughts on unplugging the solenoid if the vehicle is still under CPO unlimited miles warranty?

JettaRed

iTrader: (1)

I keep going back to the XENTRY TIPS, topic number LI07.70-P-070763 dated 01-14-2020, that identifies the solenoid as a "non-essential part" and that the DTC will not cause a CEL and should be ignored. If the failure of the solenoid was truly harmful to the engine, Mercedes would not make such a statement.

JettaRed

iTrader: (1)

Of course. Anything controversial that he says, unless it can empirically shown to be true, creates a huge liability risk for him and his business.

BDC90

If that covers a blown engine , why bother? MB will blame any mod as a reason to skirt warranty.

kevm14

Ok so we have learned that if you see an engine DTC in generic OBD-2 mode, that is positively correlated with requesting a MIL (CEL). So if you have a CEL and want to be sure it isn't because of your oil pump valve, check via generic OBD-2. If it isn't listed there that's NOT why your CEL is on (and the real code(s) will be listed).

I don't know that all hope is lost. Plugging in a new solenoid may correct the issue. I have my doubts that the ECU is trying to correlate oil pressure to oil pump valve operation. Obviously, it COULD do this if it has an oil pressure sensor, but I don't know why they'd go through the hassle to write all that code. Furthermore, that code criteria is a circuit code. Circuit codes are not the same as sensor performance codes. So since it's the same code as everyone else, I would bet that plugging in a spare solenoid would satisfy the ECU. Again, this is my hypothesis. Only one way to prove it...

Regarding the Tasos video, I haven't watched yet. But my 2 cents is that I do not require his buy-in to consider this safe. Given his position as a business owner, I could certainly understand not wanting to endorse this. There are certainly downsides to endorsing it. What's the upshot for him?

kevm14

Somehow this link is broken for me. This should work for others: https://mbworld.org/forums/mercedes-...es-me-cel.html

WRC-LVR

"Any thoughts on unplugging the solenoid if the vehicle is still under CPO unlimited miles warranty?"

well if it needs service and they find that unplugged, they may plug it back in. And they may think you have tried to muck with the car, thereby voiding the CPO warranty ( at least they may try to do that...)

kevm14

Because of the drivability improvements.

He would likely end up in court to prove that unplugging the sensor did not cause the engine failure.

Alternate option: unplug and enjoy. In the event of needing to use the engine warranty (up to and including total replacement), simply plug sensor back in before bringing the car anywhere. Yes it will have a history code, but with no CEL, you can simply play dumb.

If they conclude the sensor malfunction somehow caused the engine failure, well, the sensor is still part of the engine and should be covered. They can't prove you unplugged it at one point (unless you documented it here.....).

juanmor40

Are you sure your CPO warranty does not have a time limit? Say 4 years, unlimited miles? I had seen that one often for MB CPO's

BDC90

Alternate option: unplug and enjoy. In the event of needing to use the engine warranty (up to and including total replacement), simply plug sensor back in before bringing the car anywhere. Yes it will have a history code, but with no CEL, you can simply play dumb.[/QUOTE]
And this is My plan as I have an aftermarket warranty, the difference in driveability and grins is worth the unplug.

PeterUbers

on the m274 ... would still love to see this for m157 if it's truly applicable to all engines

As you're seen, we are possibly coming to see that it does possibly cause a CEL in other m157 models (per a tech post on Kenny's video and let another member a few posts up with a 2015 s63 couple)

zk2004mb

Thanks! I fixed the link in my post. Turns out to be a bad hyperlink

juanmor40

@PeterUbers , Here is my take on it, and would love to be enlightened on the topic.

The harness of the M274 is not as resilient as the one on the V6/V8?
Interesting the use different part numbers for the M274 and M276. Likely length differences, but quality?

Q: why is the code more often on the M274?

zk2004mb

I know people have different thoughts on disconnecting. To those who decide to keep everything in the factory way, at least we should add a sacrificial harness to the solenoid as we did on CPS and cam solenoids. I found leak on the plug when I pulled it out.

It's the same harness on cam solenoids. 2 pin to 2 pin

kevm14

For whatever reason the pass-through harness on the M274 is failure-prone. This led to many vehicles presenting with this code. MB looked into it and determined that it's not worth repairing. No other applications seem to have chronic circuit issues like this so MB has no bulletin for them to say it's non-essential (even though it is).

BDC90

Kevm14 when do You start selling these?

TomZVB

I thought it was interesting the ability to see drivability changes based on engine health/wear. While I trust what he’s saying in the video, I have read about the various dislikes of the MCT even on a new car - the sluggishness, gear hunting, etc. I had never driven an MCT car until mine was delivered, but based on what I read, I knew what to expect. And it was exactly as explained. However, when I unplugged the solenoid, all that went away. The responsiveness at low revs was markedly changed - the driving characteristics of the car were markedly changed. Yes, my car has high mileage, but the engine is quiet and it starts with barely a tap of the button. I would say that it’s in very good health.

If I’ve read other responses correctly, then I believe that similar results have been seen with even low mileage cars (across the 6 cyl and 8 cyl engines).

My thinking here is that he has to err on the side of protecting his business with regard to should you or should you not.

Unplugging was the right decision for me.

I was hoping he’d provide more detail around piston oiling and bore-scoring prevention. Perhaps in a future video?

TomZVB

My SL63 did not throw a CEL. It has also been regularly maintained by MB so I’d assume it’s had “some” software updates throughout its life.

Might just be an S63 thing.

ImolaSix

Few things to consider about Tasos' video:

1. I disagree about the cold oil causing excess stress to the oil pump. The literature states that even with the solenoid plugged in the the ECU reverts to "high" oil pressure mode during cold start. The pump has a relief valve at 60 psi. Whether that limit is reached with cold or hot oil, it does not matter, 60 psi is 60 psi, the oil pump will not be stressed beyond this. Use common sense and do not run a 5w50 in an extremely cold climate. During a cold start a 0w40 will move through the oil galleries faster before hitting the 60psi bleed off.

2. Not sure where he is getting the 23 psi piston oil squirter number from as again the MB literature states specifically that under "low" oil pressure mode (30 psi) the squirters are off. Will be asking this in the comments of his video as he must have some intimate knowledge of the true characteristics of the ball valve for this application.

3. Not exactly sure what he means about the oil "not lasting" with the pump in "high" pressure mode. Is he referring to the engine burning more oil, or does he mean the oil will shear faster? I agree that 15,000 km oil changes have no business on a TT V8.

I agree with others here that he is not going to outright say to unplug as the liability for his business is too high.

JettaRed

iTrader: (1)

It's probably too soon to make that connection empirically, though anecdotally, the connection is there. We may never have an ironclad link between the two because of the impact it would have on Mercedes and other manufacturers that use a 2-stage oil pump. After all, how many non-AMG cars has cylinder scoring been shown to be a problem? And what percentage of AMG engines have failed because of oil starvation? It may be more financially advantageous to just warranty failures instead of a non-safety recall or an engineering change. It would be interesting to know if the new SL43 engine uses this oil pump configuration.