Oil consumption on the 5.3L LC9 V8

One version of GM's 5.3L V8 burns oil through worn piston rings. It matters which version: this is the LC9, the Gen IV engine, and the settlement that resolved it names a specific and fairly narrow list of trucks and SUVs. The later Gen V engines in the same models are a different design and are not covered.

Symptoms

Oil level dropping between services without a visible leak, fouled spark plugs, a rough idle, hesitation on acceleration, and a check engine light. The oil gets burned in the cylinder rather than lost underneath, so the driveway stays clean.

Likely cause

The piston rings wear more than they should and stop sealing oil out of the combustion chamber. Oil burnt alongside fuel fouls the plugs, which is why the first thing an owner usually notices is how the engine runs rather than how much oil it has lost.

How should it be checked?

Check the oil level between services rather than at them, and read the plugs. On a covered vehicle, look up whether the settlement claim was made — a repair already paid for under it is documented, and an engine that was never addressed is still the engine it was.

How can you check it yourself?

Check the oil on level ground with the engine cold, note the level, and check it again after a few hundred miles. Ask to see the plugs, or at least ask when they were last replaced and why.

The question to ask the shop

Which 5.3 is in this truck — the VIN identifies the engine, and the LC9 is the one this applies to. Has it ever had a consumption test, a ring or piston repair, or a claim under the settlement?