I run Castrol 20/50. I try to change it every 2000 miles.

Whatever's on sale, 30 or 10W-30 and change it every 3000 miles.

that's some really thin oil you're using dd!

i try to run a 20W-40 - but most of the time it ends up being 20W-50.

i make it a habit to change my oil as little as possible and change my filters every 5000klms - i just top the engine up afterwards.

30 weight is not thin ... it's thicker than 20W-50 isn't it?

Nissan recommends for the 1200:
Temperature range
0C - 32C (32F - 90F): 30W
-20F to 104+: 10W-30 or 10W-40

It rarely gets over 90 here in Seattle. I think the record is 99 degrees.

They didn't have 20W-50 back then, but 20W-multi is good down to -10F. 50 seems pointless, sure it's OK for starting at above 100 degrees, but so is 10-40W and engine oil runs at 200 degrees ... even with 30W oil. The different weights are for when the engine is cold.

The thing about 10W-30 is the quality is/was more consistent than other multi-weights... some auto makers had to warn about using certain 10W-40 brands back in the early 90s ... OHC camshafts were wearing out. But all the 10W-30s passed their tests. Maybe oil has gotten better since then.

the only reason i thought you had thinner oil was a friend of mine ran castrol 0W-30 in his RS Liberty because his engine builder told him to.
his hydraulic lifters collapsed because the oil was too thin when at running temp and subsequently destoyed his engine.
he ran 20W-50 in his new engine and hasn't had a problem since...

does that suggest the the 0W-30 is the thinner oil then? i'm confused...

0W oil is what ... "thick as water"? I hadn't heard of this before.

10W is used in sewing machines, is it not? Very thin.

90W is the thick stuff used in our differentials and gearboxes. I would be surprised if we couldn't/shouldn't be running newer thinner oil, for better economy and faster shifts. Our 1978 Honda Accord used 10W-40 oil in the gearbox.

Multi-weights vary by temperature, and have 'wider' operating ranges. They pour easy in freezing weather (unlike 30W) but don't thin out too much in hot weather (like 30W). Best of both words is the idea. But not really necessary unless you live somewhere temperatures vary that much. Automakers like them because they increase fuel economy when the engine is cold.

Here's more accurate and authoritative information: Vavoline.com's Oil Viscosity article.

sweet.
thanks for the info

A friend of mine ran a 0w-30 fully synthetic oil and seized all his bearings after about 1000km, he would have serious bearing rummble on start up and would take a while for oil pressure.

now he is using castrol flutron

Nicholas

I do not think it is the fully synthetic that buggered your friends engine, but rather the viscosity.
Castrol Futron is also fully synthetic or at least part synthetic.
BUT the viscosity is better.(I cannot remember now but it is not 0W-30)

I ran Castrol GTX2 but they have released in South Africa a replacement called Castrol High Milage.
All my cars still have little miles on them and I do not want to use these type of oils that are thicker to prevent oil usage due to wear.
I want to see if it uses oil so that I can know how serious the wear is.
I now have changed to Engen Super 20W-50.
It is the only oil that is approved by Volvo for South African conditions.
I have heard some Volvo 850 T5's here coming in just for a routine service with
450 000km on the clock.
These volvos have turbos on them.
We all know how much stress a turbo puts on oil.
Engen is the south african brand name for Mobil.
Mobil changed a few years ago to this name for south africa.
So I was informed.