2000 Sienna Sludge?


#1

2000 Toyota Sienna with 118,000. When i remove the oil cap the exposed metal is coated in a hard black substance. is this a sign of sludge? the car doesnt exibit any of the signs of a sludged engine. Toyota checked the engine and confirmed that there was no sludge. what is this stuff? should i be concerned?

Thanks!