Dissolving sludge after change to Penz Plat?

[CR94]

... For example, when hot it's often lighter than when I check it cold.

Likely it appears lighter when hot only because a thinner layer clings to the dipstick when hot, not because the color would be lighter for equal depth.

 

[kschachn]

Right. Different antioxidants used and DI packages. Every car I had the oil got pretty dark fairly quickly. But it also depends on the temperature of the oil. For example, when hot it's often lighter than when I check it cold.

I’ve noticed the same thing, probably due to the film thickness on the dipstick.