I'm preforming the GM TSB 10-06-01-008G: for oil consumption on 5.3 engines with active fuel management.
2007 Avalanche, I have to pour 4-5 oz's of GM solvent into each cylinder.

1. Remove the spark plugs and ensure that none of the pistons are at top dead center (TDC).
2. Clean the pistons by putting 118147 ml (4-5 oz) of Upper Engine and Fuel Injector Cleaner, GM P/N 88861803 (in Canada, use 88861804), in each cylinder. Allow the material to soak for at least 2.5-3.0 hours, but no more than three hours and then remove the cleaner. A suggested method of removing the cleaner is cranking the engine over. Make sure to unplug the ignition coils and fuel injector before cranking the engine over. Also make sure that the painted surfaces are covered so no damage is done.

My question is how far past top dead center do I need to be to get 4-5 oz's of solvent in each cylinder at the same time.
Does anyone have a 5.3 engine sitting around with the heads off so there is no guessing?

Thanks in advance,
Jamie

 

This is a ThirdGen F-Body forum, and nothing in that series used the SBC Gen III/IV design engines - Especially none with the cylinder-killer programming.

If this were a Gen I SBC, I would advise that the crank turned to 45° past TDC for #1 would insure that no pistons were at TDC, and that if you pulled all the coil packs and plugs you would be able to inject a few cubic inches into each hole.

Also, if this were a Gen I SBC and if somehow DID happen to have the cylinder-killer AFM software, I would advise that you re-flash the PCM to diable that function.

 

As Vader said, this topic doesn't really belong in this forum, however I went through this issue with my 2010 Silverado and give you some insight on my experience. I don't know the specific answer to your question regarding how to position the crank to make none of the pistons are at TDC. I will say that when I went through this process with the dealer still under my powertrain warranty, they said that most of the time, trying to free the stuck rings didn't work and they ended up going ahead and replacing the pistons and rings later on anyway. So, with mine they just skipped that step and did the oil pan baffle, valve cover and pistons/rings in one shot. They did the whole job with the motor in the truck, but had to remove the steering rack, front differential and crossmember to get the oil pan off. I never disabled the AFM system before or after and I drove it for another 20K miles after the fix before I sold it and didn't have any further oil consumption issues. I traded it in 2 years ago for a 2018 Silverado, so I have no idea if the issue came back. From what I understand, GM added the oil pan baffle and updated valve cover sometime around 2011 and didn't have these issues from then on. A coworker had a 2013 Tahoe and never had this issue, so seems that GM eventually figured it out.

The root of the issue is the oil vapor in the crankcase produced by the AFM pressure relief valve at the oil pump getting sucked by the backside of the rings of the deactivated cylinders (cylinders under vacuum when AFM is active) and also oil getting sucked into the intake manifold through the PCV system. The added baffle in the oil pan and redesigned valve cover that moved the PCV port is the fix to keep it from happening again, but once the rings are caked with burnt oil, they usually need to be replaced.

If my truck was out of warranty and had this issue, this is what I would do.
-Get a tuner an disable the AFM system (this deactivates the AFM blowoff valve in the oil pan, so you won't need to do the baffle)
-Replace the valve cover with the updated GM version (easy to do, so why not)
-Try the GM top end cleaner in the cylinders as you have described (what do you have to lose?)
-Change spark plugs
-Run a good quality synthetic oil

If all of that gets the oil consumption to 1qt or less per 2000mi, then I would stop there and just drive it. If it was still burning more than that, then I would go ahead and pull the heads and oil pan, change the pistons/rings and add the baffle to the AFM valve in the oil pan while I was in there, but this would be my last resort since its so much work.

Good luck.