6th Oil Sample for 2008 Impala

[Marika]

Here's the results from the 6th oil sample for my 2008 Impala. It's finally reaching "normal".

[Bruce Nunnally]

Thank you for posting; I enjoy these.

[Cadillac Jim]

All those numbers look wonderful from the beginning. It does look like the 5W-20 has more molybdenum than the 5W-30, possibly because it has just a trace of moly sulfide in it for film strength on cold starts.

The most interesting thing to me is that the silicon content of the oil has gone down to near zero, which tells me that piston wear has stopped. This is in line with my experience that most GM engines run forever if properly maintained and not abused to an extreme amount. I'm happy to see proof on paper that the 3.5 liter V6 continues this tradition.

Another interesting tell-tale is that the zinc levels are holding up for 3.500 miles on the oil. This means that the ZDDP is not being depleted, another indication that the normal wear level for this engine is just about zero, yet more proof that the tradition of GM durability is alive and well in your 3.5 liter V6.

I don't know where the copper is coming from. From the casual dismissal of copper levels in the note from Blackstone, they do and don't think that this is important. I suspect it is from the oil cooler lines or the oil cooler element in the radiator tank.