Doc,
Im currently using a 5w40 grade diesel specific oil with an API rating of CJ-4....
But according to an engineer I've talked to he said that the 5w40 is "too thin" for the climate here, and might cost some trouble in the long run... also, he said that the more appropriate oil here is in the range of 10w and 15w however, Im still satisfied with the performance Im getting with the 5w40 oil...but Im quite concerned about what he said with regards to it causing me trouble in the long run...
also, as I so much want our both ends to meet, I cannot find a Synthetic diesel oil in the ranges of 10w and 15w
because its either a synthetic one but not diesel specific or the other way around...
So may I know whats your take on that?

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