2009 Corvette Coupe, LS3 engine, A6 trans.
Bought new, now at almost 60k miles
Always use Mobil1 5W-30, GM filter, changed at 30%-50% Life Remaining (5k-9k miles)
Just as a hobby, I send a sample to Blackstone Labs from every oil change. Lead level is typically 7-9, and other metals are normal.
At 37,096 miles/7,711 on oil (Sept 2011), lead spiked up to 13. Copper was normal, Tin went from 0 to 5. Blackstone said it was probably a particle streak in a bearing, don't worry about it. Sure enough, the next two changes with about 7k miles on each, showed lead dropped back to 8 which is normal and tin was 0.
At 59,458 miles/8,699 on oil (May 2013), lead spiked up to 17.
All other metals normal, copper actually dropped a little and Tin was 1. Blackstone says this is still not a big deal, but they are wondering why it's happening. So am I.
If it's a particle streak, what could be causing it? Could changing spark plugs or cleaning MAF dislodge something that sticks in a bearing?
I don't track the car, though I often corner it hard in the twisties. But on street tires (PS2 runflats) and keeping the oil 1/4 - 1/2 qt above the Full mark (recommended 1 qt above for real racing), oil starvation seems unlikely.
Any comments on the significance of these numbers, or what do do differently?
Bought new, now at almost 60k miles
Always use Mobil1 5W-30, GM filter, changed at 30%-50% Life Remaining (5k-9k miles)
Just as a hobby, I send a sample to Blackstone Labs from every oil change. Lead level is typically 7-9, and other metals are normal.
At 37,096 miles/7,711 on oil (Sept 2011), lead spiked up to 13. Copper was normal, Tin went from 0 to 5. Blackstone said it was probably a particle streak in a bearing, don't worry about it. Sure enough, the next two changes with about 7k miles on each, showed lead dropped back to 8 which is normal and tin was 0.
At 59,458 miles/8,699 on oil (May 2013), lead spiked up to 17.
All other metals normal, copper actually dropped a little and Tin was 1. Blackstone says this is still not a big deal, but they are wondering why it's happening. So am I.
If it's a particle streak, what could be causing it? Could changing spark plugs or cleaning MAF dislodge something that sticks in a bearing?
I don't track the car, though I often corner it hard in the twisties. But on street tires (PS2 runflats) and keeping the oil 1/4 - 1/2 qt above the Full mark (recommended 1 qt above for real racing), oil starvation seems unlikely.
Any comments on the significance of these numbers, or what do do differently?