Changed my oil today using Redline 10W30 as always (lots of track use), but the color of the oil in one of the 5 bottles was different from the others. The color is usually a reddish gold, but from this one bottles it was a greyish gold, and at the bottom of the bottle was a bit of grey residue (like graphite powder?). I've also seen this residue at the bottom of Redline MT90 transmission fluid before (and interestingly not in all bottles). Can anyone offer an explanation for these observations, and is it a problem?

 

The color of the oil is typically a combination of component color and dye. The fact the color is different from bottle to bottle indicates they may have come from different batches and/or you purchased oil that's been on the shelf a while. This is also indicated by the residue at the bottom of the bottle. Worry? No real need to. You may want to change the oil out earlier than normal though - due to the fact the detergent package may have broken down a little. If you're really worried though, just get some fresh oil and change it again ... no worries there.