The '02 Corolla and oil thing

The seals for API energy conserving oil is not just on some of the bottles; it is on all of the bottles of certified oil.

You mean if it's API, it's always Energy Conserving?

API stands for American Petroleum Institute, the people who make the standards for oil. You can get oil that is certified by the API that is not energy conserving, so it could have the API label, but not be energy conserving.

Yeah ok, got that. But the Motorcraft that I got for $4 a bottle has both.

Looking forward to it.

"Energy Conserving" means it has friction modifier additives in it that regular oil doesn't. It is for this reason that you aren't supposed to use EC oil in motorcycles that have a wet clutch that runs in the engine oil, the EC oil can be too slippery and make the clutch slip.

This is also why you aren't supposed to use Dexron III trans fluid in a Chrysler that specs ATF+3 or +4, and probably also Toyota's T-IV and WS fluids. ATF+3 and 4 are "slipperier" than Dexron hence Dexron causes clutch pack grabbing and binding that wrecks the trans and causes harsh shifts.

No, if it is API, it will have an API mark on the bottle. If it is API Energy Conserving, it will have an API Energy Conserving mark on the bottle.

Gotcha. Well I bought the latter, in Motorcraft for $4 a bottle.

I usually by Castrol or Quaker State synthetic motor oil when it's on sale for 30 - 40% off at Canadian Tire. I keep a jug or two in reverse for the next oil change.