10W-whatever

Whats the big Difference between Oil. 5W30-20W40 or what else they make. Does it effect preformence, lubrication, what is the real difference, and if there is, which is the best to use?

Whats the big Difference between Oil. 5W30-20W40 or what else they make. Does it effect preformence, lubrication, what is the real difference, and if there is, which is the best to use?
here you go


http://www.nordicgroup.us/oil.htm#Oil%20Viscosity


got it from
http://www.nordicgroup.us/oil.htm



and another
http://www.performanceoiltechnology.com/saeviscosityclassificationsandmanf.requirements.ht m

Its a good rea, alot of links in there as well to help find specific answers.

Basically, the big factor in the viscosity is the engine's bearings. Bearings in an engine are just a flat round ring of metal that surrounds the polished journal of the rotating part. The oil pump sends pressurized oil into the tiny gap between them via a hole. The rotating part then rides on a cushion of oil and (in a properly working system) the rotating metal never touches the bearing at all.

If you try to pump oil thats too thick, it won't be able to fit oil in the gaps fast enough, especially when its cold. If you use oil that is too thin, its easily compressed out of the gap and lets the rotating part contact the bearing.

The other big factor is your climate. Back when I was in PA, I used a thinner oil so that it wouldn't be like molasses at 6am in February. Out here in CA I can run the same oil year round and since I know I won't have really cold temps, I can usually run a touch thicker oil. Still within spec for the engine's parameters, but I use the oil pressure gauge to tell me.

In truth, over time the bearings and journals wear and the clearances increase. If I have an older engine, I like to install an oil pressure gauge (if there isn't one already) and get rid of the dummy light the just says "oil". If I notice that oil pressure is under my comfort level, its an indicator that either the oil pump is wearing out or the bearing tolerances have worn past acceptable levels. There is a good chance that the engine will still last a while, but to band-aid the problem I switch to a slightly "heavier" weight oil. Like if I'm running 5w30, I might go to 10w40. Rarely I need 20w50.

The short answer is use what the manufacturer recommends. But DetroitMuscle has some great links to help you understand why.

Thanx for the links, I'll check them out soon.

Those links were a great help. And thanks moderator for the basics. great help