[oil pan 4]

I go by the milage, apperance, smell of the oil and how it beads and spreads out when dripped onto to a smooth surface.

The oil still looks new after 3,000 miles in the lincon. It gets its oil changed every 7,000 to 10,000. The lincon gets synthetic rotella.

In the hyundai its oil still looks really good even after 7000 miles. It gets oil changed every 10,000 to 12,000 and about the time more oil needs to be added. This one gets the hord of 10w-30 mobil1 synthetic I stole on sale for $2.50/Qt last year.

With my diesel the oil is always black even tho I hand built the engine about 2 years ago, put around 10,000 miles on the engine so far and change its oil every 3000 to 4000 miles. This one gets rotella synthetic (winter oil) or rotella synthetic blend (summer).
Its oil is always blacked out, it doesn't matter what I do.

I was cleaning out the garage last month and found like 8 gallons of SL rated synthetic rotella I bought on sale 3 or 4 years ago so every thing will be getting 5w-40 after the mobil1 runs out.