Full syn 5W40 vs Semi 10W40 15W40.

[BDK]

For some reason in Australia there's very few 10W40 full-syn and no 15W40 full-syn but plenty 5W40 ...

I also think there is only really 1 true full syn oil that is the Penrite 10 tenths PAO/ESTER.

Would a 5W40 full synthetic be much better than a 10W40 Semi or 15W40 mineral for Australian conditions ?

 

[charbaby]

What engine will the oil be going in?
If it’s a diesel, then you will want an oil that is diesel rated for better soot control.
The full synthetic would be my choice for a petrol/gasoline engine.
However, we still need a bit more information on the application(s).

 

[CleanSump]

Make, year, model, engine, mileage?

 

[BDK]

It's a diesel 2013 Nissan Patrol Common Rail 190.000km that asks for.....copy paste from manual :

For europe API CF-4 ACEA B3 or B3/E3 or JASO DH-1
Except for europe: API grade CE CF CF-4 or JASO DH-1

* For Pickup models for South Africa API grade CF-4 or JASO DH-1 is recommended.

And for viscosity just to select form the classic temp/viscosity chart

Also wondering if It would be OK to use Valvoline Restore and Protect 10W40 full synthetic in a diesel to clean in up? even though it does not have diesel specific ratings.

I've read somewhere that diesel engines do not get deposits like petrol engine so it's pointless?

''I wouldn't bother with that restore and protect oil. Diesel engines simply do not build up deposits in the same way that gasoline engines do.''

 

[userfriendly]

None of the above. To clean up an engine, Diesel or otherwise with outside temperatures above 10C, use a high soluble group one SAE 40 like Delo 400.
2. Disable the EGR.
For temperatures below 10C, down to minus 20C, find the cheapest CK -4 15w40.
Colder than that, use the appropriate winter grade, xW40.
A famous person once said “ prove me wrong”.

 

[CleanSump]

I think the 2013 come with a DPF. You have ULSD there now, right?
190.000km is barely broken in even on a little diesel. It shouldn't be dirty unless it didn't get oil changes.
In your climate a 5W-40 synthetic would be just as good as a 10W. You might want to consider an oil listed for MB 229.51 or 229.52. They're quite good and the Mobil ESPs and European brand oils are pretty good at keeping things clean. At least my OM642 that supposedly is a sludge monster has remained bright and shiny inside for 265k km with Mobil 1 ESP and the first few OCIs with Fuchs and Pentosin. Penrite is very popular there too, not a bad choice either.

 

[Japanese]

For some reason in Australia there's very few 10W40 full-syn and no 15W40 full-syn but plenty 5W40 ...

I also think there is only really 1 true full syn oil that is the Penrite 10 tenths PAO/ESTER.

I would use 5W-40 synthetic Penrite in this case.
Is it this one?
https://penriteoil.com.au/assets/pis_pdfs/HPR DIESEL 5 5W-40 (Semi Syn.).pdf

* For Pickup models for South Africa API grade CF-4 or JASO DH-1 is recommended.

I would use a dedicated diesel API CF-4 oil. However, the current standard is API CK-4.

Also wondering if It would be OK to use Valvoline Restore and Protect 10W40 full synthetic in a diesel to clean in up? even though it does not have diesel specific ratings.

Don't use Valvoline Restore and Protect because is an oil for gasoline engines and is not API CF-4/CK-4 rated.

 

[BDK]

No DPF , so I've got plenty of 15W40 CK-4 semi-syn or mineral but no full-syn CK-4 or plenty of 5W40 Full-syn but only 5W40 A3/B4 is CK-4 a better spec for diesel engines than A3/B4?

Found a penrite full-syn CK-4 10w40 https://penriteoil.com.au/products/enviro-10w-40-full-syn

API CK-4 & MB-Approval 228.52 (E+10W40)

 

[SC Maintenance]

I have not seen a 10W-40 full syn here from any major supplier either. Lots of 10W-40 conventional or semi. I have used the Havoline 10W-40 conventional not long ago?

I think the likely reason is no OEM has spec'd that weight for decades. Maybe the boutiques still make it. Lots of 0w,5w and 15w - 40 around. Go with one of those that meets your spec.