6.2L Carbon?

[Bucky1]

I understand with the direct injected engines that carbon buildup can be an issue. Also understnad that carbon can contribute to piston slapping noise as well.
How are you guys or do you decarbon these 6.2L engines?

 

[gooffeyguy]

If it's flex fuel capable run a couple tanks of E85 through it.

E85 runs cleaner and will actually clean up the combustion chambers of carbon.

2001 Yukon SLT
2012 Yukon XL Denali
2011 Yukon Denali RIP 5/20/18

Sent from my SM-G930V using Tapatalk

 

[Larryjb]

I just came across this thread. Carbon buildup in direct injection is often related to the intake side of the intake valves because direct injection is no longer washing the valves. I don't think carbon buildup in the combustion chambers is a huge issue as long as you are using top tier gasolines.

So I would repeat Bucky1's question, specifically regarding carbon buildup on the intake valves.

 

[bobsr]

I just came across this thread. Carbon buildup in direct injection is often related to the intake side of the intake valves because direct injection is no longer washing the valves. I don't think carbon buildup in the combustion chambers is a huge issue as long as you are using top tier gasolines.

So I would repeat Bucky1's question, specifically regarding carbon buildup on the intake valves.

I did some work on these "top tier" gasolines, as that is what GM recommends in their owner's manual. Hard not to have to read it when you have a Denali with all the "stuff" that comes with it and you have no clue how to use it all and make it all work for you.

Locally I used "gas buddy" to find the least expensive Premium Gas in the area, and I found a newly opened BP station that has the Amoco 92 as their premium gas. Price was the lowest in the area at $2.49 per gallon. (opening special). But it can easily go over $3.00 per gallon for the "top tier" gas, so I guess I have to check and see who is at the lower end for a fill up.

GM makes a big deal about using this "top tier" premium gas, which in the old days we might have laughed at. But with this 6.2 it's probably best to "follow orders" from the manufacturer, when you hear of all the problems some members have been having. Same with the synthetic oil now, also not an option to not use it. Although I used Mobil 1 since new it on my 5.3 2003 Yukon and got 325,000 miles out of it!

Let's hope the carbon and the "new 8-6-4-" technology does not come back to cost us big time. I don't think there is any E 85 available in very many places in New Hampshire, and some of the lists on the internet are old and the places are gone. But I had the "flex fuel" option in my 2003 Yukon and maybe got one or two tanks full when in Pennsylvania or other states where it is more common.

Both AAA and Consumer reports did some research and checked out the "top tier gas" with the additives, and reported "top tier" gasoline had 19 times FEWER carbon deposits on injectors, intake valves, and in the combustion chamber when compared to regular gasoline, without the "top line" additives.

They also found a "clensing effect", reducing intake valve deposits by 45-72% when used over a 5,000 mile test. The variations appeared to be attributed to the specific detergents used by the various brands.

Here is the link below, which includes all the brand names of the guys who can be called "top tier" because they use the recommended detergents that GM and others recommend in their gasolines. I don't think it's "fake news," but these days you never know... Check it out!

https://www.consumerreports.org/car-maintenance/study-shows-top-tier-gasoline-worth-extra-price/

 

[gooffeyguy]

Where does the fuel get "injected" in these "direct injection" engines?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Hi-psi]

Where does the fuel get "injected" in these "direct injection" engines?

As the name implies, directly into the cylinder. So as @bobsr described above, since you don't get the "washing" effect of the atomized fuel going over the intake valve, DI engines have a higher occurrence of carbon buildup.

 

[Hi-psi]

 

[thompsoj22]

I was completely unaware of GM LT direct injection, It isnt a bad thing but no matter what you put in the fuel tank it will have no effect whatsoever on the pcv carbon/solids buildup on the backside of the intake valve. Knowing this, I think a catch can should be your first remedy.

 

[thompsoj22]

I understand with the direct injected engines that carbon buildup can be an issue. Also understnad that carbon can contribute to piston slapping noise as well.
How are you guys or do you decarbon these 6.2L engines?

The carbon buildup is specific to the backside of the intake valve and in no way influences combustion chamber carbon buildup/piston slap.