Polyphenyl sulfone is very resistance to car engine oil at operating temperature. I remember Stratasys made a prototype oil filter from that and ran it on a car for quite some time.
Are there mechanical property requirements? PTFE and various fluoroelastomers are used in these types of applications. For strong and stiff, consider polyamides, PPS, and PEEK.
80W90 is a lubricant used for gear applications such as hypoids for automotive axles. Yes, they can contain sulfur additives to provide EP (extreme pressure) performance.