I was just wondering if i could go ahead and change my oil to a 5W-30....she runs on a 10W-40 now...
as far as i now its the oil viscosity when its cold and hot respectively....(correct me if i'm wrong)
i think i should make this chage coz she gives me white smokes when reved for 2 1/2 - 3k rpm for sometime....
also i end up reving her upto to 5k - 6k rpm sometimes and dont wanna kill the engine so much....she has a 131k miles on her...

Also whats the difference between synthetic and noral oils?
which one is more preffered and why?

cheers!

 

isnt white smoke a sign of a blown head gasket? either way i dont believe that changing the oil like that would fix it...

 

Well....dont get a white smoke all the time....but sometimes on a morning start or when its revved for a real long time sitting at a place...like the other day i was jump starting my friend's Civic....she started giving me traces of white smoke...

 

Look under the oil cap for a white goop. White goop = head gasket.

Also, remove the rediator cap, and rev the car up hard. Bubbles usually = head gasket.

The first number is the weight of the oil, and the second is the viscosity. The difference between synthetic and conventional is small. The lubricating power is the same of both, but the way they degrade is different. Synthetic lasts longer and doesn't sludge up as much. Synthetic also performs at higher temps where conventional cannot.

Maybe its also worth doing a compression test. You can get one for about $15 bucks at autozone.

 

So, all other issues aside, why 10-40 in the first place?

 

Basically your oil choice is based on the temperature of the area you live, and the size/performance of your motor.