Corolla 1994 oil

I would use the oil specified by the automaker. The viscosity should be listed either on the oil filler cap or on the dipstick.

No, he means what should he really, really, really use! Seriously though, my 95 Prizm says 5W30 on the filler cap, so that is what goes in.

Either is fine. If you live in a cold climate, the 10w30 would have the edge, if you live in a warm climate then the 10w40 is a bit better.

The first number is how well the oil flows when cold. Since both are the same, then the oil will do the same thing. The second number is how well the oil holds up in high heat conditions, the higher number being a bit better than the lower number.

Most cars these days will perform just fine on 10w30 year around. In a severly cold climate, one can use 5w30 in winter, and in an extremely hot climate one might want to use 10w40 or maybe even 20w50 in summer. As a practicle matter, there is very little need to use 20w50, but it's there if you want it.

Or better yet, follow Ray O's advice and use what it says to use. Don't you think those automotive engineers might know more about what should be used than we do?

Besides what is screened on the oil filler cap, the owner's manual will show optional viscosity if the vehicle will remain in extremely warm or cold conditions for the duration of the time the oil is in the crankcase.

I doubt if even Key West sees 3 or 6 consecutive months of temperatures over

BTW, I believe that the reason that Toyota does not list 10W-40 is because of its effect on fuel economy.

The instruction manual says 10W - 30.

About 10" thick

I always agree that following the directions is the best option, but in the face of confusion, 10w30 and 10w40 are functional equivelents. The 30 is better in cold weather, the 40 is better in warm. Either can be used as a year-around oil in my area.

I agree with Ray on that one.

I think I would use the 10w30 though, mostly because I'm pretty sure that Key West seldom dips below 40, and this would make the 5w oil thinner than I might like. Thicker oil takes longer to form drops ... ;-)

Multi-viscosity oil means that the oil is thinner when the temp is cold and thicker when it is warm.

Exactly. My cars drip when they sit, so I would use the higher numbers on the oil. 10 takes longer to drip than 5 will take, all other things being equal.

Your owner's manual has much better information in it than the dipstick or oil cap. Most manuals have a chart that lists the recommended oil weights based on ambient temperatures the vehicle will be operated in. I found that my Toyota truck responded very well to 20W-50 for most of the summer down here in the South (GA and FL). And, typically dropped to

"Jeff Strickland" wrote in news:NYKdnYl1TZmyFSPZnZ2dnUVZ snipped-for-privacy@ez2.net:

That statement can be badly misunderstood. We all understand that even a

Huw

I was wondering if you were lurking....

Welcome back...

Thanks. Never really been away ;-)

Huw

Every time I see an 'oil' question, I'm sure you are out there to set us straight.

Upon re-reading, it does sound contrary to common sense ;-)