Oil

[kempj1 0]

Due for a service & I've read up on my oil recently.

Thinking about putting some 0W30 Mobil1 in this time.

Apparently the number before the 'W' is an indication of the viscosity of the oil when it's cold. The number afterwards is for the viscosity when hot.

Thinner oils reduce pressure, but increase flow. When your oil's hot this means that heat is taken from the hot bits more quickly.

Pressure increases with RPM, and the flow increases with pressure - up to a certain point.

There is a pressure cut off in the engine which means that when this pressure is reached there will be no additional flow as the RPM increases.

I think I need the oil to be as thin as possible when cold because most of the time the engine spends half a journey warming up (going to & from work, etc).

Thinner oil also means less work is required to pump it. => less power wasted.

I also checked the working temperature ranges of several oils, and Mobil1 seems to have a very high flashpoint - effectively the temperature at which your engine explodes.

I've never seen my oil temp above 110degrees, which is much lower than the flashpoint of all engine oil. My old GTi got upto 124degrees on the Nurburgring, and was absolutely fine.

Does anyone have any experience experimenting with oil ? Any thoughts on whether 0W30 Mobil1 is suitable for a VR6 with 85k miles on it ?

Many thanks, James

[coullstar 2]

This has been discussed many times on loads of forums but for the life of me I cannot remember the definitive answer although I think 10w-40 is the minimum recommended for use. I think that going to 10w-50 or 60 is even better.

[Ultimatetune 0]

10- 60 or 10-50 or 15-50, but would not want to use a lower gradient if you drivee the car hard

[kempj1 0]

I'm a bit new to all this - I don't know all the factors involved, but I'd have thought that thicker oil would be better for trundling about rather than redlining it. So why if you drive it hard do you want the thicker 50 or 60 weight oil ?

[craggsy 91]

I use synta silver and had no probs

[Ultimatetune 0]

the vr engine gets bl**dy hot and you need an oil that can cope with the temperatures generated, oil will break down very quickly if it working outside of its perameters

[kempj1 0]

Fair enough - that's what cought my eye when looking at the analysis of the light weight Mobil 1 oils - they tend to have a far higher upper limit to their operating temperatures compared to most others. The same can be said for a few other oils, but the analysis didn't cover Synta Silver.

The interesting thing with the heat is - yes, the worst thing that can happen is for the oil to start breaking down, but if you go for a lighter oil you get a larger volume of oil flowing through the engine. This means it gets shot of the heat better and reduces the running temps.

But a balance needs to be struck - maybe I'll go for 40 rather than the 30 weight, just to be on the safe side...

I'd be interested in hearing from anyone who runs (or has run) light weight oil in their VR though.

[FishWick 21]

I use Silkolene Pro S 10W/50 in mine and won't use anything else. As far as full synths go, and this is ester - the best you can get, it's good value at

[Ultimatetune 0]

kevhaywire is right and silkolene is good stuff