Originally Posted By: FlyNavyP3
I completely disagree with the previous comment about the aluminum coming from the block. For starters, it has a cast iron block. Even if it was an aluminum block it would have steel/cast iron sleeves or some other exotic material for cylinder liners. Aluminum block engines rarely have aluminum cylinders (I can't think of any off the top of my head). Due to the lack of lead in the sample, the more likely answer is that the aluminum is from the piston skirts and quite likely the engine bearings. I agree with others to check the air filter and to check for other vacuum leaks that would allow un filtered air into the engine. Since this engine uses roller camshaft followers aside from an outright failure, the iron is not likely coming from the cam. I'd strongly suspect dirt ingestion combined with her short trips as the cause of the high wear numbers.
I don't know the exact metals used in this engine, but most cylinder blocks in recent cars are aluminium alloy and when the block or liners (If it has them) are corroded or subject to extreme wear a UOA will show a higher level of Aluminium. There is no way in UOA terms to know if it is from corrosion of the pistons or cylinder walls.
THE SILICON FIGURE IS NOWHERE NEAR HIGH ENOUGH to cause the high Iron or Al figures and short tripping is not the cause, as it does not show significant fuel contamination.
The limit for long term wear rates for Si should be around 30 ppm for a 5K mile OCI, BUT that will only cause a very minor increase in wear metals.
Driver style during cold starts in particular can double some of the wear metals, but I doubt if that is the cause although it could be a factor in this case.