Oil Burning 2013 GMC

[ksa8907]

I would highly suggest a "catch can" on the pcv system. I made a cheap one out of a water supply sediment filter and some fittings for under $50. In 5k miles it will catch maybe half a quart, and thats not even all of it, i need to make more modifications to it.

[oil pan 4]

If I ever built/ran an LS3 series engine it would not have AFM for this reason alone.
Fuel mileage up, but oil mileage way down, not a good trade IMO.

If you were burning that much oil your catalytic converter is likely well on its way to being clogged with oil additive ash.

[pgfpro]

Originally Posted by ksa8907

I would highly suggest a "catch can" on the pcv system. I made a cheap one out of a water supply sediment filter and some fittings for under $50. In 5k miles it will catch maybe half a quart, and thats not even all of it, i need to make more modifications to it.

On the older ones this was a fix to some degree. After talking to a GM mechanic "off the record", he said my truck already has the supposedly fixed items. He said its the design of the cylinder deactivation that is the cause. When the deactivated cylinder runs through its deactivation cycle the rings are floating and not sealing oil because there's no combustion to expand them to the cylinder wall, and this lets oil gets past the top ring. This also causes the ring pack to get gummed up in a hurry and then it even makes the problem compound itself.

IMHO the design was a complete failure from the beginning. GM knows this and also knows what the cost would be to fix it. Can you say another Bankruptcy.

[Fat Charlie]

It looks like a good trade off: A gain of several mpg in normal driving at the expense of having to add a quart of oil periodically.

A lighter oil, maybe letting the additive chemists have a go at it first might be the easy part of the fix. Getting Murricans to check critical fluids once in a while will be the hard part of the fix.

Once reformulated oil is developed and put in the pipeline, the recall would simply be a matter of getting folks in for a free oil change (make it a flush) and a pamphlet explaining the new oil specification. It'll be a bonanza, not a bankruptcy: how many maintenance items are going to get sold at the same time people are in for the "free oil upgrade?"

[oil pan 4]

Motor oil has been reformulated at least 5 times since the 1980s.
Each reformulation pulls more and more anti-wear additives and detergents out of the oil.
There are around 1/2 to 1/3 the anti wear additive and as little as 1/4 the detergents found in the old formulations.

Pulling additives out of the oil is not an oil up grade, it is in fact an oil down grade.
This is a prime example of just because something is new doesn't mean its better.

I say gut the converter if you can get away with it and run SH or SJ oil.
SH oil was formulated when petro chemical and automotive engineers only cared about the oil doing 2 things, 1 minimizing wear and 2 protecting against sludge build up.

Originally Posted by pgfpro

IMHO the design was a complete failure from the beginning.

Just like the first time they tried it in the 1970s.
But back then the oils were loaded with detergents so the piston rings never gummed up with crud.