Carbon Buildup On Valves

Anthony Owner New York Posted   Latest   Edited  
Unsolved
Driveability
2015 GMC Sierra 1500 5.3L (C L83 Flex) 6-spd (6L80)
Need Info

hi Diag Net. '15 100k 1500 5.3l GM truck. we are replacing high pressure fuel pump. Noticed carbon buildup on cay #1 intake valve. see photo. 

we are not an engine shop, i do not want to be an engine shop. my question is how much carbon buildup is too much carbon buildup and at what mileage will this cause a problem? there are a few euro shops around town doing some type of “walnut blast” service. i do not know much about this and would like some info. 

thx in advance

0
Interesting
Obie Technician
Washington
Obie
   

That is not a significant build up. If it was the valve head would be obscured and the port would have carbon on it. Symptoms are misfire/rough running cold and possible idle problems. Severe cases cause high speed misfire etc. I think you are okay with this engine. I have seen engines with half that mileage and 5 times that carbon build-up.

+3
Ð Awarded
Agree
Cody Diagnostician
Illinois
Cody
   

I would call that a low to moderate amount of carbon. Seen alot worse. But I'd would let the customer know it could potentially be a problem in the future and recommend some kind of cleaning service.

+1
Ð Awarded
Agree
Eric Manager
Arizona
Eric
 

Put it back together and run a can of CRC intake valve cleaner PN05319 through it. We have had great outcomes with it. If you have a Blue Chem dealer in the area theirs is even better. We perform a carbon cleaning ever 20-30K for our customers and have had very little trouble with carbon. This vehicle is getting close to problems.

0
Ð Awarded
Andreas Owner
New Mexico
Andreas
 

I don't know much about these cars. If it is port not direct injected just run some injector cleaner. BG CRC, Techron etc. Should clean it up no issue.

0
Ð Awarded
Steve Mobile Technician
Arizona
Steve
 

Direct injection don’t clean valves

0
Ð Awarded
Mark Engineer
Colorado
Mark
 

Steve Great reminder for us that the direct injection configuration (GDI) doesn’t keep intake valves clean and thanks. However, some of the OEM gave the owner a benefit by having conventional fuel injection as the primary system of fuel injection at lower RPM (maybe below 1,200 RPM when vacuum is highest). So when vacuum is high the engine has traditional injection to keep intake valves…

0
Ð Awarded
Tomasz Diagnostician
Ontario
Tomasz
 

Seen much worst. This amount shouldn’t cause issues.

+1
Ð Awarded
Agree
Cliff Diagnostician
California
Cliff
 

That's good for a 100k on the odometer. The last one I did only had 50k on it and the valves were about the same as what you showed.

0
Ð Awarded
Mike Owner/Technician
South Carolina
Mike
 

Berryman has a great product for carbon removal, need to add this to service menu to prevent carbon buildup

0
Ð Awarded
Boruch Owner
Ohio
Boruch
 

We do walnut blasting when indicated. That one is not too bad. The walnut blast I use is from Harbor Freight and I buy their fine walnut shells as well. It makes a mess even with a shop vac handy. There are guys on EBAY making adapters for many engines but it still makes a mess! In your case you could put it back together and if you have a a fuel injector cleaning canister, SUR&R sells an…

0
Ð Awarded
Brandon Diagnostician
Arizona
Brandon
 

It's not terrible but I personally would recommend getting them cleaned, being a gdi motor the airflow is critical for “proper” mixture and to prevent hot spots on cylinder walls.

-1
Ð Awarded
Inappropriate
Ronald Owner/Technician
California
Ronald
 

That is not too bad but not too good. They writing is on the wall that issues will come up. I believe at some point, GM was reprogramming to ignore misfires on cold start up on some vehicles. We see this all the time on VW and Mazdas. We pull the intake, close the valve and use spray carb cleaner and picks and clean them off and down the road they go. I would jump through fire to avoid pulling…

0
Ð Awarded