oil change
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Change it when the DIC indicates you need to or if you don't drive the car much, once a year.
Pro
Joined: Oct 2007
Posts: 679
Likes: 4
From: TremontonUT UT
I bought my 04 this past Feb. Since there were no service records in the car I changed the oil immediately using Pennzoil Platinum 5W/30. I sent a sample to Blackstone for analysis. This is what they said:
FRANK: All wear metals read at or below universal averages after 3,002 miles of oil use. Universal
averages are based on an oil run of 4,100 miles. The oil was in good shape physically containing no gas or
anti-freeze. The viscosity read in the normal range for a 5W/30. Insolubles (oil oxidation due to heat, use,
and blow-by) were low at 0.3%, showing good oil filtration. The air filter was working well with silicon reading
low at 5 ppm. You have a nicely wearing engine in your 2004 Corvette. Check back to establish engine
wear trends after your next ~3,000-mile oil run.
I ran this oil/filter another 3000. This is what they said this time:
FRANK: Thanks for the note. We don't think taking the sample from the filter changed much. It could have
resulted in slightly higher metals, but filters usually aren't efficient enough to capture these microscopic
metals. You ran this oil about twice the miles of the last, and we think that's the likely reason for the wear
increases. Nothing is out of line, so if you want to go longer on your next sample, that should be fine. We'd
recommend 7500 miles. Insolubles, which are oxidized solids caused by heat, use, and blow-by, read low at
0.1%. Looking good as of 7/2/09.
Even after 6000 miles the insolubles, that I think a lot of folks think are some kind of acids, look outstanding. I have decided that 6000 is where I will change mine. If for no other reason than piece of mind send in a sample at one year. Later! Frank
FRANK: All wear metals read at or below universal averages after 3,002 miles of oil use. Universal
averages are based on an oil run of 4,100 miles. The oil was in good shape physically containing no gas or
anti-freeze. The viscosity read in the normal range for a 5W/30. Insolubles (oil oxidation due to heat, use,
and blow-by) were low at 0.3%, showing good oil filtration. The air filter was working well with silicon reading
low at 5 ppm. You have a nicely wearing engine in your 2004 Corvette. Check back to establish engine
wear trends after your next ~3,000-mile oil run.
I ran this oil/filter another 3000. This is what they said this time:
FRANK: Thanks for the note. We don't think taking the sample from the filter changed much. It could have
resulted in slightly higher metals, but filters usually aren't efficient enough to capture these microscopic
metals. You ran this oil about twice the miles of the last, and we think that's the likely reason for the wear
increases. Nothing is out of line, so if you want to go longer on your next sample, that should be fine. We'd
recommend 7500 miles. Insolubles, which are oxidized solids caused by heat, use, and blow-by, read low at
0.1%. Looking good as of 7/2/09.
Even after 6000 miles the insolubles, that I think a lot of folks think are some kind of acids, look outstanding. I have decided that 6000 is where I will change mine. If for no other reason than piece of mind send in a sample at one year. Later! Frank
Burning Brakes
Joined: Jun 2007
Posts: 1,047
Likes: 69
From: Hanover MA.
I change the oil in my vette every fall before it goes into hibernation. This past year I only drove it 1800 miles. It didn't get a lot of use this past summer as the Boston area weather really sucked. 
