Originally Posted By: Marisa
Originally Posted By: Garak
Something like the RP HPS would be a possible winter choice and does have decent anti-wear content, but is thinner than what is normally used in a TDI, and really doesn't have much in the way of diesel specifications. For example, my old Audi 200 gasser had 5w-30 as an allowable grade, particularly in winter, with 15w-40 the preferred grade through most "reasonable" winter temperatures (i.e. not Saskatchewan). I experimented a bit with it and found it drank the 5w-30 fairly heavily. I had few problems with the 15w-40.
I also experimented with Mobil Delvac 1 ESP 5w-40 and Royal Purple 0w-40 (A3/B3 A3/B4 type lube) in all weather conditions, and found both to work well. The Mobil 1 TDT is of similar operational viscosity to these two options and also to T6.
I would stick to something with an HTHS of 3.5 or greater, with a preference for an approved lube. Others here are much more experienced with the approved lubes for your vehicle. If I were in your shoes and decided to venture out of spec, it wouldn't be as far as a thin gasoline type 5w-30, even though the anti-wear compound levels are fairly high in the RP HPS. Royal Purple does offer Euro type 0w-40 and 5w-40 (the latter has the Synerlec additive), along with HDEOs and a 10w-40. Of course, there are many approved lubes, not to mention various HDEOs in 5w-40.
Just got 35% off at pep boys and a $60 rebate from Mobil for 5 gallons Mobil Delvac 1 ESP 5w40.
That's also a great oil, and a great price. It should work very well for your intended use.