I just bought a 91 S5 NA rx7 and Ive noticed when I warm it up then try to rev, it smokes alot past 5500. I am thinking oil seals but the car only has 113kmiles and when I drained the oil it looked so thin and watery for a RX7. I replaced it w/ 20w-50. I havent suspected anything else for a engine rebuild so what do you guys think I should do. Any hints for oil changing or how much to replace oil seals. thanks

 

oil burns noticeably blue.

White smoke can also equal leanness (BUT... that seldom happens)

Smell the smoke? If its sweet smelling, you're burning coolant.