I purchased a used 2005 C6 (#96) from GM. It was supposedly used by a GM engineer. The story was that the first 100 Vetts are given to members of the Design and manufacturing teams to evaluate and feedback early production improvements. This was one of the last given out. The OnStar did have a Detroit phone number, so some of this could actually be true. Anyway, It had 8800 miles on it and looked very well kept. When I bought it I checked the oil level, and the stick was wet up to about an inch above the cross hatching. I figured it was just splash in the tube, and was satisfied that it wasn't low. The % life remaining was 35% so with that many miles, and assuming it hadn't been changed I figured the car hadn't seen much abusive treatment. I have had so much fun with the car, I totally forgot about the oil level. The pressure was good, always hovering around the middle of the gage with about a 10 PSI swing (35 to 45). So, I wasn't even thinking problems. When the weather changed I started the detailing process and thorough inspection now with 10500 miles. I found the oil level to be consistently high no matter how I measured it. This was not tube spatter, it was showing about a quart high. I figured the best thing to do was just change the oil, putting in the correct amount and then establishing that as the base line (thinking maybe the stick is wrong). Bottom line the new fill reads perfect on the stick, so I was at least a quart high. Does anyone know if I could have done damage? The owners manual warns against overfill but doesn't quantify. The pressure reads the same, no new noises, so how much is too much? I didn't drive it that hard (no wheel spinning) but had it over 110 mph a couple of times between radar traps (no long duration). I took 4 trips of about 3 hours each, but who knows what the other guy did.

 

Relax. They give you plenty of wiggle room either way. You almost certainly have not hurt anything.

 

No worries. A quart over is no big deal. From what I understand, it's actually reccomended to slightly overfill for certain racing situations.

 

A high oil level causes the crankshaft to dip down into the oil and whip it into a foam. The oil pump can't pump foam very well and the oil temp goes up and there may even be an efffect on oil circulation.

Will one extra quart cause any problems? I doubt it. And you would have known something was wrong when driving it. With the C5 the manual actually recommended adding an extra quart when it was raced since oil consumption was high while racing. Fugetabouwdit and enjoy it.

Was there much of a discount on the purchase price ?

 

Yes, I thought it was pretty good, $6500, plus I got to use my owner loyalty of an additional $1500. "Service after the sale" was less than satisfactory for still paying $46K, but that sting sort of fades.

 

GCarrHarris,

Take a look at page 2-22 under "Racing or Other Competitive Driving"....read it all but note excerpt, "... check oil level often during racing or other competitive driving and keep the level at or near 1 quart (1 L) above the upper mark that shows ..."

Doesn't mean the previous owner raced it but it may mean he knew his manual.

 

Definitely don't sweat it.
Better a quart too high than a quart too low.

 

Especially with synth