Its not rubbish at all. My WH is not fitted with a DPF therefore doesn't need .51 spec oil.
It was rubbish, straight away someone posted their uk CRD has a filter lol
Read the thread properly.
considering mb oil spec. If you have a read of the data sheets you will see that the .31 carries the same considerations with regards to low ash etc as .51 (Merc state the oil must not contribute to or cause emission problems and specifically mention particulate filters) so in that respect ie filter considerations it makes little or no difference but of course we need to take heed of what merc recomemd
There are .3 and .5 standards but if you look around all the good quality oils seem to just go for .31 and .51 . I guess it's just coverall with no detriment perhaps
However the .51 & .31 refer to the engineering of the oil and not just it's ability to work with the particualte filter. Essentially there's a list of things and it simply measures the level of achievement of the oil as outlined in Mercs info sheet "requirements in respect of engine oils " you can't simply say I don't need .51 because I haven't got a particulate filter. Mine recommends .51 and I don't have a particulate filter. If yours recommends different well there you go but it's a bigger picture.
However we digress from the main point of the thread, viscosity recommendations ................
Filter equipped cars in the uk are recommended w30 , in the US w40. Same engine fitted to wk, same company , why ?
No filter cars w40 worldwide unless different is needed for operating conditions.
The joker in the pack or the conundrum is the advice from oil companies who,lets be honest unless you're one of their boffins and I suspect you're not
probably know a lot better than us the ins and outs of it, reflect the uk advice.