Thread: What TDV6/SDV6 engine oil are you using?

Originally Posted by DiscoDB

The Penrite Full Synthetic 5W-30 looks to be a bit of an anomaly if the published technical data is correct as it is actually thinner at 40 and 100degC than HPR0 0W-30.

Unlikely, would be a different base stock oil between the two. Viscosity modifiers work to thicken the oil at hotter temperatures (thicker than it would be without the additive) so the 0W/5W of the viscosity grade would tell me that you cant have the same base stock oil which is why the 100deg viscosity would be slightly different between the oils. SAE 30 100deg viscosity range specify viscosities between 9.3 - <12.5 cSt. SAE 40 12.5 - <16.3cSt

Originally Posted by shanegtr

Unlikely, would be a different base stock oil between the two. Viscosity modifiers work to thicken the oil at hotter temperatures (thicker than it would be without the additive) so the 0W/5W of the viscosity grade would tell me that you cant have the same base stock oil which is why the 100deg viscosity would be slightly different between the oils. SAE 30 100deg viscosity range specify viscosities between 9.3 - <12.5 cSt. SAE 40 12.5 - <16.3cSt

True - perhaps more of a marketing anomaly due to the way the grading works. It is just interesting that by 40degC, the 0W-30 Full Syn is already slightly thicker than the 5W-30 Full Syn. Obviously the 0W-30 oil can go to a lower cold starting temp.

Pity they don’t also publish the 0degC viscosity. It is what is happening between 0degC and 40degC that would insightful - especially with the use of multigrades.

Originally Posted by DiscoDB

Pity they don’t also publish the 0degC viscosity. It is what is happening between 0degC and 40degC that would insightful - especially with the use of multigrades.

Easy enough to calculate with a viscosity index calculator.

There's a couple of good online ones available

I've seen xW-40's with a lower visc in that range than xW-30's, it just comes down to base oil type and the amount (and type) of viscosity index improver used

Originally Posted by rick130

Easy enough to calculate with a viscosity index calculator.

There's a couple of good online ones available

I've seen xW-40's with a lower visc in that range than xW-30's, it just comes down to base oil type and the amount (and type) of viscosity index improver used

Yes good for estimating but the actual measured result at 0degC would still be good to see for comparison.

Castrol Edge A3/B4 5W-40 looks to be a good compromise option if you ignore not meeting the Ford Spec, but consider HPR5 as being too thick at cold start temperatures, and the 5W-30 oil as being too thin at hot engine temperatures (above 100degC).

The problem I have with the Ford spec is it is centred around US driven fuel economy targets at the expense of wear protection. It is also for new engines, not worn engines.

Can’t wait to get an oil pressure gauge fitted to see what is happening over summer and winter.