How: Disconnected the low-pressure oil pump solenoid on my m276 (2013 GLK 350)...

Solved:
- Engine rattle on startup (when hot)
- Low rpm rattle when driving around town

+ And the engine feels more responsive and smoother

I'll report back if any fuel economy change, but regardless I am leaving it unplugged. The engine feels much healthier and just like it should from the factory...

Pretty shocking, wanted to share. I was thinking about upgrade the timing chain tensioners... not anymore.

More info:
https://mbworld.org/forums/w212-amg/...solenoids.html

Interesting concept. Another case where chasing tiny incremental improvements in gas mileage (to meet CAFE standards) causes MUCH bigger problems than it solves.

My only question is, is there a similar (bad) system on the M272 engine? It seems to be devoid of most of the issues of the later version engines, and of course, the GLK never had an issue with the balance shaft problem since that was sorted by 2008...

The m276 has TSB's on startup rattle for pre-2014 models

I had the symptoms and my engine falls within the "replace timing chain tensioner and check valve"

Deactivating this low-pressure solenoid just fixed it

How did you figure it out? The oil pump is mechanical right, how can it be controlled ? Where is the sensor ? I have a 13 with some noise.

Hmmm. There are folks with 2014+ reporting the same

What about this example (I may have misunderstood the diff):

https://mbworld.org/forums/glk-class...-rattle-2.html

There's an old saying, "only time will tell". 🙂

Where's confident evidence this works for others IN THE LONG TERM?? Doing this disconnect "fix" may alleviate the noise, but not the underlying issue

I just read this: https://mbworld.org/forums/w212-amg/...solenoids.html

and made a decision for myself

Running at "normal" oil pressure has solved these problems for me

Time will tell... the chain tension and VVT are all oil pressure driven

Car is running great and I'm happy

Will provide an update if I ever notice symptoms return

Until then, I'm happy to be running "normal" oil pressure

From everything I read, it sure seems like a safe and sensible "modification". Basically all you're doing is to eliminate the "low oil pressure operation" of the engine under certain conditions. And given the issues that the M276 has with oiling, that can only be a good thing (IMHO, YMMV).

FWIW these are the benefits I had when I first unplugged it: https://mbworld.org/forums/w212-amg/...ml#post8963720

Different vehicle but same engine.

Here is the survey (linked in the big thread) of people with different models and engines unplugged: https://forms.office.com/Pages/Analy...g1Mkw1WkJVNS4u

How do I unplug sensor 2013 Glk 350

The linked threads (very long) do show diagrams of the location of the sensor. Looks like it's just to the right (car's right) of the crankshaft pulley, and reached from underneath (only). There are photos and diagrams showing the location.

This is correct, depending on if you have 4MATIC or not, you might be able to do it from the top here are some helpful links I gathered: https://mbworld.org/forums/c450-c43-...ml#post8979570

I guess the low pressure is so pressure is kept low when motor is cold to not over pressure if you drive hard. Does this go bad?

I think it's entirely a fuel economy thing

Low pressure is ~25psi, "normal" pressure is ~55psi

If you go from underneath, after removing the underbody panels, it is very easy to access.

Please see the big thread: https://mbworld.org/forums/w212-amg/...enoids-96.html

Update: Car runs great.

No noticeable difference to fuel economy.

No rattle noises on startup and more responsive acceleration at low RPMs

This is why I want to measure oil pressure , I have same noise , it’s gone when warmed up but how much damage has been done already? Probably an expensive amount

.
And this quote from Post #15 in this thread:
Hey, @Bertie_ ... so, since you know you're getting 25psi and 55psi, why not provide the tools / parts and the steps required to determine the engine oil pressure, since other folks out here are trying to get the psi (?).

Beautiful glad you are enjoying the mod.

Does this "mod" result in any perpetual warning light(s) on the dash? Just curious, since I don't have a gasser.

nope only a soft code. CEL only on model year 2019 and + MBs as well as most S-Class vehicles.

OP, here is something else (yes, another mod) you could consider as well, I want to do it but my connector is weird, maybe yours is more normal and you can enjoy it instead: https://mbworld.org/forums/mercedes-...s-voltage.html

I have a C350 2013 (M276) with startup rattle as well, and my engine also falls under the "replace chain tensioner and install check valve" category.

Might try this mod, since it fixed the startup rattle for you.

You still haven't replaced chain tensioners and installed check valve, right?

Another suggestion I got from a retired Mercedes mechanic was to try thicker motor oil.