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Hey guys! Recently purchased a W212, equipped with the M276 motor with 110k miles. No issues whatsoever, rides super smooth. I’m interested in walnut blasting the intake valves as a preventative maintenance item, but haven’t found any shops near me that work on MB in the NJ/NY region (even called 5 local dealerships). Saw some videos of other car makes where they remove the intake plenum, place the piston at TDC, then soak the valve with sea foam or an equivalent. I’m thinking of doing this but wanted your advice as I haven’t found anyone attempt to do so on this motor. Any advice is appreciated 🙏🏻
2016 E350 4Matic wagon, 2019 Ford Expedition, 2019 Chevy Bolt EV
run premium major brand gas through that thing, and it will be fine for it's whole life. or if you must use offbrand cheap gas, then run a can of Techron through it with every few gas tanks, and at least once in awhile, drive it hard with the revs up to burn off any accumulated carbon.
walnut blasting is something you might do if you've already got the engine apart and its really crusty inside. it is definitely not something you want to take the engine apart just to do on a maintenance basis.
That is not preventative maintenance. That is overhaul. As stated above, use premium fuel or an additive such as techron. if these engines dumped fuel pre cylinder than buildup may be an issue. Not really a concern for direct injection. The injector itself then becomes the concern. There are additives for cleaning direct injection.
First off, thank you all for the supportive advice. My main reasoning for wanting to do this was the lack of service/maintenance history on the car; but since it’s in great condition and functions properly (smooth acceleration, steady idle) it does sound like a waste to do such an unnecessary project. It’s currently being maintained with high quality fuel (93/e85) & oil (liqui moly). Also read an interesting point brought up by fellow member “diesel_dan” on a different thread citing MB motors don’t have carbon issues other manufacturers do, do to “better liquid knock down so, the oil doesn't get into the PCV stream as easily.”
Carbon cleaning valves is overrated. No one who's made it to a quarter million miles with a DI ever cleaned the valves, much less with chestnuts or whatever.
That is not preventative maintenance. That is overhaul. As stated above, use premium fuel or an additive such as techron. if these engines dumped fuel pre cylinder than buildup may be an issue. Not really a concern for direct injection. The injector itself then becomes the concern. There are additives for cleaning direct injection.
Originally Posted by Senecat
Carbon cleaning valves is overrated. No one who's made it to a quarter million miles with a DI ever cleaned the valves, much less with chestnuts or whatever.
That is actually not true. DI engines DO have an issue with carbon build up on the intake valves because they do not see fuel to keep them clean. The carbon build up comes from the PCV system. Some engines are very prone to this and others not as much. Audi and VW really have an issue with this and the walnut cleaning is what the factory recommends. In fact some OEMs have two sets of injectors now, the primary DI and then port injection just to help keep the intake valves clean.
So all DI engines do have this occurrence, again, some need it a lot more frequently than others.
Chris
EDIT..Techron or any fuel types or additives will not clean or solve this issue with DI engines. It would have to come through the intake if it were to work at all.
Last edited by badbenz94; Feb 25, 2022 at 08:59 AM.
That is actually not true. DI engines DO have an issue with carbon build up on the intake valves because they do not see fuel to keep them clean. The carbon build up comes from the PCV system. Some engines are very prone to this and others not as much. Audi and VW really have an issue with this and the walnut cleaning is what the factory recommends. In fact some OEMs have two sets of injectors now, the primary DI and then port injection just to help keep the intake valves clean. So all DI engines do have this occurrence, again, some need it a lot more frequently than others. Chris EDIT..Techron or any fuel types or additives will not clean or solve this issue with DI engines. It would have to come through the intake if it were to work at all.
my statement was referring to keeping the injector nozzle clean, not the valves. Sorry for any confusion. I have not personally seen any issues with build up on DI intake valves, exhaust...yes. in any case the process the op asked about is overkill to the extreme.
If one wanna learn of his/her engine carbon build up status at the intake valve, by all means do it. We all then can learn some too. Good for everyone.
Supposedly MB engines are not so prone to excessive carbon build up like older or early 2000s Audi and VW Tsi engine.
Some BMW also known to have more carbon build up than the Benz.
Here is a good example of newer 2019 Golf engine ( supposedly cleaner ) and the inherent carbon build up a DI engine will have, be it little or plenty....at 10,000 miles.
Surely engine oil and fuel quality will matter in carbon build up reduction, but having oil vapor on purpose injected into our NOT A PORT FUEL INJECTED engine as part of "green" , will introduce carbon build up at your intake valve,
like it or not.
Last Dec 2021, I was tempted to remove my intake manifold ( at 34,000 KM ) to be able to see and clean carbon build up at my intake valves, but I changed my mind because
I have to remove lots of wiring assy connecting to sensors which so happened to sit above the intake manifold. Also there is a wiring plastic box hiding the wire assy with fragile clips which is a pain to undo, need special tool to be safe.
I already have all the gaskets. Sending my probe camera was impossible, some kind ofpartitions inside the intake manifold was blocking.
Below are photos during a fun project inspecting/improving/cleaning engine bay grounds. This is for 276 3.0 Turbo owners if they want to do valve cleaning, components you need to remove.
1st remove the ECM & bank 1 + 2 air filter box - EASY
Removing the cover of the wiring assy plastic box is a pain in the azz, if you do not want to break any of the 15 or so plastic clips.
A special fish hook shape tool must be made if the un-clipping to be done without risk of breaking those clips. None of those plastic interior prying tool kit work for this clip.
Below is the FEMALE clip to be pried 20 degrees or so.
The above female clip, latches itself at the MALE notch below.
Apology for my poor drawing, but below is what the special tool would need to look like.
Special Tool must be metal, thin and stiff. The interior plastic prying tool is too flexible and too thick. The FEMALE clip is very stiff.
When the plastic box cover opens up, these are the wire assy needed to be removed side way and most may need related sensors/devices connectors to be first unclipped. Damn, a real hassle.
I cant , at that point in time, totally unclip the most rear part of this plastic cover, those near the fire wall. I think 3 more FEMALE clips to go. I can't see them well and no room to work with ease.
M276 3.5L NA seems so much easier to do upper intake manifold removal.
The best image of carbon build up I can get was thru the spark plug hole, but its too difficult to assess based on those, but it is evident my valves have some carbon build up. https://mbworld.org/forums/e-class-w...ke-valves.html
The part I hate the most on my engine is the position of the aftercooler is in front of the main pulley and so tight, I can't fit the size 27mm socket to spin the crankshaft to see more
valve opening. So aftercooler must be removed to spin crankshaft. DUH.
The last time , 2 months ago in Dec 2021 when I did remove my aftercooler to clean oil leak traces from timing cover and replacing all 4 camshaft magnets which my version supposedly will leak and introduce oil into
ECM wire assy, I forgot to inspect the intake valve via probe camera thru the spark plug hole ....errrggg.
However, I plan at 50,000 KM to inspect and clean the intake valves for preventive maintenance & learning sake.
That means 3 years from now
Carbon cleaning valves is overrated. No one who's made it to a quarter million miles with a DI ever cleaned the valves, much less with chestnuts or whatever.
run premium major brand gas through that thing, and it will be fine for it's whole life. or if you must use offbrand cheap gas, then run a can of Techron through it with every few gas tanks, and at least once in awhile, drive it hard with the revs up to burn off any accumulated carbon.
walnut blasting is something you might do if you've already got the engine apart and its really crusty inside. it is definitely not something you want to take the engine apart just to do on a maintenance basis.
Glad to hear this. My '16 S212 (bought new) is coming up on 90K miles, and I've recently decided to try and make it my forever car.* I've been running a bottle of Techron every 10K miles since new.
*For the record, I just turned 61. According to my investment advisor, the actuarial tables estimate I'll live to 81. So we're talking about 20 years here.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by crater64
...For the record, I just turned 61. According to my investment advisor, the actuarial tables estimate I'll live to 81. So we're talking about 20 years here.
Don't you just love these guys? A couple of years ago, my wife and I were pondering whether to retire. Our financial advisor said we could if we didn't go crazy spending money. He also reminded us that we maybe had just another good 15 years to enjoy retirement. Turned in my papers the next day!
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