I have just been advised by a mechanic who fitted my DPT box, that there are problems with the Castrol Oil recommended by VW.

He quoted a customer of his who has 190 VW transporters which have the DPF (He fitted them all with the DPT power box) They had problems with the Castrol Oil which had a high ash content and was affecting the DPF. They have now solved the problem by switching oils to one made by A9, a french company which is a fully synthetic 10/40.

He did say that Castrol may have now changed the formula for the VW recommended oil, but wasn't 100% sure.

Not just Castrol is recommended by VW, several other major oil manufacturers make oil that meet the appropriate 507.01 standard. Fuches and Shell are just 2. What you have in the engine now could be any of these, as the service centres tend to use what they can get the best deal on.

The halfords VW507 or millers VW507 oils will be fine both in 5L not 4L tins.

Why they put a 10w-40 in a PD140 I don't know either as that's too thick.

If you don't have a DPF it was originally VW506.1 0W-30 and to make life simple they can all run on VW507.0 5w-30 as that doesn't cause DPF issues.

Most PD140 don't have DPF anyway, but I'd say that a 10w40 on variable is the wrong oil.

castrol edge.. recommended here..

Fuchs Titan GT1 Longlife lll here

shell helix longlife vx will do fine!!!