Remedy for carbon buildup on intake valves? holding RPMS at 3k + for min 20 minutes?

[KGMtech]

Saw this posted on Reddit, the poster referenced a VW patent that showed that DI buildups could be removed if a warmed engine was held at 3000 RPM for at least 20 minutes. Idea was that if the intake valves were allowed to get warm enough for long enough the buildup would be ingested into engine and burned away. Other aspects of the VW patent were suggesting that if engine oil contained enough carbon dissolving solvents the DI buildup might not be an issue.

With modern cars trying to keep revs so low with either 8 or 10 speed transmissions or CVT, the average car spends very little time at 3k RPM and it would be only the BITOG type that would force this routine onto their car for the possible burn off of DI gunk.

What say you?

 

[thastinger]

IDK, carbon deposits are pretty hard, not sure I would want those goings through my engine. I have, so far, been able to avoid the purchase of a GDI engine for this exact reason.

And if this method worked, the VW kid in my neighborhood that never gets out of 2nd gear, the one with the coffee can exhaust, would never have this issue.

 

[I<3oil]

If that was the case, any highway trip at length would perform similar action...

 

[Kira]

Rig a fitting into the intake for cans of "GDI Valve Cleaner" and spray the stuff while on open road trips.

 

[chris719]

No, the only thing that works is mechanical cleaning. All those sprays and cleaners are barely effective or completely ineffective. There are a few good tests on YouTube.

 

[Dave9]

No

Patents mean little until proven in real world applications.

 

[StumblingElk]

If your talking a DI engine without any port injection then I don't see where this would help.

Italian tuneups have their place but this isn't one of them, imo.

 

[dnewton3]

Saw this posted on Reddit ...

What say you?

You read internet theory garbage.

There's no reasonable belief that running an engine for "Yy" minutes at "X,xxx" rpm will solve a problem which took tens of thousands of miles to develop.
If it were that easy, and it was under patent, it would be in every VW owner's manual, and the rest of the OE automotive aftermarket would be clamoring to get a piece of that action.

 

[skyactiv]

It doesn't work. I once had a 2013 GTI 6 speed manual I bought new and read about the trick early on and did it a few times.
The intake manifold butterflys failed at 84K. There is a pic if you like seeing gross crap.

I cleaned the intake valves on my DI engine

I got a check engine light a few weeks ago that the intake manifold went out on my 2013 VW GTI. It has just over 84K on it. Lots of highway miles from my wife. I'm a semi mechanic by trade and was a mechanic at a Honda dealer before that. That being said, the job isn't difficult if you have the...

bobistheoilguy.com

 

[PontiacHO]

A wire wheel was the only way I’ve had success cleaning carbon off of valves. I’ve personally torn down engines that had stuff poured down the intake while engine was running in attempts to remove carbon from the tops of pistons because of a carbon knock. So much carbon on the piston top that it pounds the head-combustion chamber. The “squeeze” of the compression stroke along with the “carbon cleaning solution” would sometimes break it loose. Then a chunk would come loose and close the plug gap and cause a misfire. Pulled heads because of carbon knocks that wouldn’t succumb to the cleaning process also. None of these attempts would remove carbon from valve stems though.

 

[walterjay]

3K+20min=0 effectiveness.

 

[cptbarkey]

Reddit is the last place you should go for any automotive advice. There are a few safe spots, but not worth mentioning.

 

[TCL]

Keep at redline for an hour. That'll totally get rid of it.

 

[Gus_Mahn]

Port methanol injection will keep clean valves clean but won’t have much effect on dirty valves. Induction cleaning might be bad for catalytic converters and turbochargers at least Ford says so. I have wondered if a long up hill pull with a trailer would get the valves hot enough to burn the carbon off. It only needs 500f or so on the valve to burn the hydrocarbon down.

 

[Kira]

Soooo....the deposits aren't wet, gooky, dissolvable syrup. They're rock hard, baked on carbon.....kinda what I always thought.

My "intake mounted spray fitting" would have to be used every 10 minutes of operation from day #1.

 

[FatOrangeCat]

Walnut blasting for the valves is what I have seen recommended. Not cheap but is supposed to be effective.

 

[twX]

Subaru has a TSB for a procedure that involves trickle feeding a bottle of P.E.A (polyetheramine) carbon cleaner into the intake over a one hour period with the engine at 2,000 rpm. Another bottle of the stuff goes in the fuel tank, probably more to clean the spark plugs and injectors than the valves. They recommend taking the intake manifold off first to pre-clean anything accessible with carb cleaner.

 

[KGMtech]

Reddit is the last place you should go for any automotive advice. There are a few safe spots, but not worth mentioning.

Oh yes, I'm aware but I thought I would see what our experts think....and without too much delay I am reminded that I can be seen as an idiot by not just my immediate family.

 

[another Todd]

Subaru has a TSB for a procedure that involves trickle feeding a bottle of P.E.A (polyetheramine) carbon cleaner into the intake over a one hour period with the engine at 2,000 rpm. Another bottle of the stuff goes in the fuel tank, probably more to clean the spark plugs and injectors than the valves. They recommend taking the intake manifold off first to pre-clean anything accessible with carb cleaner.

Reminds me of the old Marvel Mystery upper cylinder oiler I used to see under some hoods. The cleaner is thinner, I wonder if one of those would work?

 

[TiGeo]

I believe harder driving does help so I vote for regular Italian Tune-ups . Mine looked ok at 75K in my Sportwagen when i had them cleaned..pics here you can find searching. DI Focus at 11 years/130K mi shows no signs of needing attention.