I opened the oil filler cap in my 2002 Camry LE V6 today and noticed some black stuff around the oil cap (very minimal). It was not tar like at all but almost looked like dried chocolate. I have been changing the oil every
4,000 KM and at 16,000 KM, I switched to Mobil 1 5W30 year round and now change the oil every 6,500 KM.Is what I am looking at Sludge or is it just light varnish that is not a problem?
Thanks,