Valve Covers, AFM Deflector, Oil Consumption TSB 10-60-10-008M

[dnt1010]

I just purchased a used 09 Chevy Tahoe Hybrid with the 6.0 AFM engine. Was a quart low of oil after approx 1200 miles of driving. I could not determine if the previous owners had changed the drivers side valve cover or not without pulling it off so I went ahead and swapped it out. After I removed it I saw that it had in fact been replaced at some point so I did not gain anything except for I guess the satisfaction of knowing. It was a bit disappointing to see the interior condition of the existing valve cover, it is sludged up pretty badly. I think people following GM's OLM system cause a lot of high mileage sludge issues due to delayed oil changes. Any motor oil (including synthetic) will sludge if left in for too long. For you guys that are running the OLM down to 0% before an oil change take a look at this pic (below) of the interior of the valve cover, now keeping in mind that this is a 198k miles engine and will have some buildup thsi looks excessive to me..... The previous owner assured me that it had always had 5W30 synthetic oil run in it and was religiously changed per owners manual. Anyway I have driven for another 500 miles or so after the valve cover swap and the oil level seems to have dropped a little bit but not enough to ad any oil yet. Oil pressure is good with no odd engine noises or lifter clicks so hopefully it will run a long time. It has averaged over 17 mpg over the last 1700 miles or so, pretty good for a Tahoe with a 3.5" lift / 10x20 Mayhem 8106 Hatchets and a set of aggressive tread Nitto Grapplers. I am looking at changing out the front and rear differential and transfer case fluids soon. I will be curious to see what the fluids that come out will look like. Not sure how many Hybrid owners visit here? my intial search turned up no threads on hybrids................might be a lone wolf LOL

 

[swathdiver]

I just purchased a used 09 Chevy Tahoe Hybrid with the 6.0 AFM engine. Was a quart low of oil after approx 1200 miles of driving. I could not determine if the previous owners had changed the drivers side valve cover or not without pulling it off so I went ahead and swapped it out. After I removed it I saw that it had in fact been replaced at some point so I did not gain anything except for I guess the satisfaction of knowing. It was a bit disappointing to see the interior condition of the existing valve cover, it is sludged up pretty badly. I think people following GM's OLM system cause a lot of high mileage sludge issues due to delayed oil changes. Any motor oil (including synthetic) will sludge if left in for too long. For you guys that are running the OLM down to 0% before an oil change take a look at this pic (below) of the interior of the valve cover, now keeping in mind that this is a 198k miles engine and will have some buildup thsi looks excessive to me..... The previous owner assured me that it had always had 5W30 synthetic oil run in it and was religiously changed per owners manual. Anyway I have driven for another 500 miles or so after the valve cover swap and the oil level seems to have dropped a little bit but not enough to ad any oil yet. Oil pressure is good with no odd engine noises or lifter clicks so hopefully it will run a long time. It has averaged over 17 mpg over the last 1700 miles or so, pretty good for a Tahoe with a 3.5" lift / 10x20 Mayhem 8106 Hatchets and a set of aggressive tread Nitto Grapplers. I am looking at changing out the front and rear differential and transfer case fluids soon. I will be curious to see what the fluids that come out will look like. Not sure how many Hybrid owners visit here? my intial search turned up no threads on hybrids................might be a lone wolf LOL


View attachment 211657
View attachment 211658

Welcome Darryl! A few Hybrid guys are members but not regulars. Yours is the first Hybrid I've seen that's been lifted. As for the OLM, When mine shows 30-45% it's around 5K miles. Thinking about dropping it to 4K instead.

As for burning oil and replacing pistons and rings, this is done because the rings were not set right during break-in and or the motor was exposed to dirty oil and dirty air filters.

 

[Tonyrodz]

I just purchased a used 09 Chevy Tahoe Hybrid with the 6.0 AFM engine. Was a quart low of oil after approx 1200 miles of driving. I could not determine if the previous owners had changed the drivers side valve cover or not without pulling it off so I went ahead and swapped it out. After I removed it I saw that it had in fact been replaced at some point so I did not gain anything except for I guess the satisfaction of knowing. It was a bit disappointing to see the interior condition of the existing valve cover, it is sludged up pretty badly. I think people following GM's OLM system cause a lot of high mileage sludge issues due to delayed oil changes. Any motor oil (including synthetic) will sludge if left in for too long. For you guys that are running the OLM down to 0% before an oil change take a look at this pic (below) of the interior of the valve cover, now keeping in mind that this is a 198k miles engine and will have some buildup thsi looks excessive to me..... The previous owner assured me that it had always had 5W30 synthetic oil run in it and was religiously changed per owners manual. Anyway I have driven for another 500 miles or so after the valve cover swap and the oil level seems to have dropped a little bit but not enough to ad any oil yet. Oil pressure is good with no odd engine noises or lifter clicks so hopefully it will run a long time. It has averaged over 17 mpg over the last 1700 miles or so, pretty good for a Tahoe with a 3.5" lift / 10x20 Mayhem 8106 Hatchets and a set of aggressive tread Nitto Grapplers. I am looking at changing out the front and rear differential and transfer case fluids soon. I will be curious to see what the fluids that come out will look like. Not sure how many Hybrid owners visit here? my intial search turned up no threads on hybrids................might be a lone wolf LOL


View attachment 211657
View attachment 211658

The vc actually doesn't look too bad. PO probably did oil changes with GM recommended intervals as you stated. I always change oil around 2500-3000. Although sometimes I do exceed that, but not usually.

 

[donjetman]

While in the pan to change the oil pan gasket #12612350, I installed an AFM Oil Deflector, GM# 12639759, to the AFM pressure relief valve, per TSB 10-06-01-008M, see pictures. I also installed a new oil pickup tube o-ring, Felpro#72401. The old o-ring was hard and brittle. And I installed the pan back on the engine today.

TSB 10-06-01-008M link:
https://f01.justanswer.com/ebrock63...il+Consumption,+MIL+ON,+Engine+Runs+Rough.pdf

View media item 27426View media item 27431View media item 27434

 

[dnt1010]

donjetman great pics thanks for posting that. It looks like a small amount of oil sludge in the first pic. How many miles/ Are you the original owner/ If so what type of oil and oil change intervals? I am really curious now as to how a high mileage engine is going to look inside even if the oil was changed every 3000 miles or less.
Maybe it would be best to just trade for a brand new vehicle each year and let the used car owners worry about this stuff (said the tightwad NEVER Hahahaha)

 

[donjetman]

I've seen better and I've seen worse. I bought the vehicle used(132k miles) recently. I'm the third owner. I don't know the mx history. I bought it cheap(that's me) and they took my 200k mile 02 4x4 Surburban in trade that had a lot of issues.

 

[07yukonguy]

Just came across this valve cover issue while looking up high oil consumption. 07’ Yukon 240,000kms. Needs a litre of oil between changes. Is it worth the valve cover swap or just keep adding oil?

 

[wjburken]

Just came across this valve cover issue while looking up high oil consumption. 07’ Yukon 240,000kms. Needs a litre of oil between changes. Is it worth the valve cover swap or just keep adding oil?

I would swap the cover. Will help your motor last longer.

 

[iamdub]

Just came across this valve cover issue while looking up high oil consumption. 07’ Yukon 240,000kms. Needs a litre of oil between changes. Is it worth the valve cover swap or just keep adding oil?

The concern isn't just that you're having to add a little oil, it's that the oil is being fed into the engine, and mostly all of it to the rear cylinder(s). You'd be far better off if that one liter was just leaking out somewhere because at least then it wouldn't be causing harm by carbonizing combustion chambers and possibly sticking up piston rings. You could just add oil until you got around to fixing the leak. Do what you can to reduce the oil going into the intake manifold by getting the revised valve cover and adding a good catch can.