changing oil weights

[dan2288]

Right now im using royal purple 10w40 and Im getting around 10psi oil pressure at idle fully warmed up. I want to switch to amsoil 10w30 pretty soon for the colder weather. Im just worried that the oil pressure would drop even more. What do you guys think? Would 10w40 be ok in the winter?

 

[My1GLaser]

Thinner oil will lower the pressure.

What is your oil pressure at 2k, 3k, 4k etc. rpm? It should increase about 10psi per 1k rpm increase.

10-30 and 10-40 are the same viscosity when cold, so I don't really see a problem with running 10-40 in the winter unless you have too high or low of pressure thru the whole rpm range.

 

[dan2288]

Its about 40psi at at 3k. What do you guys think of 5w40? Since its a 5 it should move good when cold and still work like a 10w40 when warmed up. Seems like the best of both worlds. Anyone running it?

 

[_-Ax-_]

Not 2 days ago my good friend with a 95 GSX asked me to come look at it. Said he had a valvetrain tick at idle. So I went and listened to it, and it sounds like a lifter or two aren't get enough oil at idle. Then when he revs it up to around 2k or so it goes away. So I asked him when he last changed his oil and he said, "just put some Castrol 20w-50 in it 2 months ago." .........My eyes got huge...... He said the heavier oil is better for turbo motors.... I realize that thicker oil gives you better/more pressure, but could this be the cause of his lifters not getting oil at idle? What's he hurting by running that kind of oil?!?!?!?!

 

[My1GLaser]

Its about 40psi at at 3k. What do you guys think of 5w40? Since its a 5 it should move good when cold and still work like a 10w40 when warmed up. Seems like the best of both worlds. Anyone running it?

Thats really good pressure. What pressure do you have at redline?

The problem with 10-40 is the amount of friction modifiers and additives they have to put in the oil to keep that spread of viscosities. It makes the oil break down faster and you lose some protection when the oil get some mileage on it. I imaging that 5-40 would be worse.

I run 15w40 Rotella. My motor seems to like it so far, and it seems cleaner then the Castrol 10-40. I chg my oil every 500 miles, but its only my weekend car and I am anal about my DSM.

 

[dan2288]

not sure about redline. I never look at the oil pressure guage when im near redline. I will next time thou. But 10w40 should be ok in the winter time then? Most people recommend 10w30 but 10w40 would have the same cold weather protection as they are both 10w, am I correct?

I think I will stay with the 10w40 just so that my oil pressure does not drop at idle. Ill just use one of those pad oil heaters that you put on the pan when it gets below freezing. They are pretty cheap so what the hell. That way I dont have to worry about the wear on the engine from the heavier oil during winter.

 

[Defiant]

You aren't in the arctic. Your current oil is fine. You don't need a heater for it. The "W" in 10W means "Winter".