If your using your diesel multigrade in a diesel that must be a good thing. And your Ford spec 5/30 is in a Ford! Many Ford duratorq turbos have been ruined by using fleet oils ie not Ford spec.
I am talking rv8 in particular the ones with crank driven oil pumps. ( Although pre serps would also benefit). Thor which bit of info would you like source for? That 20/50 mineral doesn't give as as good lubrication as 10/50 synthetic. (Or even 10/40 semi). Transit Vans run 20000 mile oil changes. With 5/30. This isn't even top notch oil either. Just the correct spec. I bet a mineral would struggle with 10000. And the engine would be scrap after 100000. The original motor craft 5/30 was a semi as well.
I am talking rv8 in particular the ones with crank driven oil pumps. ( Although pre serps would also benefit). Thor which bit of info would you like source for? That 20/50 mineral doesn't give as as good lubrication as 10/50 synthetic. (Or even 10/40 semi). Transit Vans run 20000 mile oil changes. With 5/30. This isn't even top notch oil either. Just the correct spec. I bet a mineral would struggle with 10000. And the engine would be scrap after 100000. The original motor craft 5/30 was a semi as well.