When I suddenly discovered one day that the GTX I had just put in my car did not have the current diesel engine rating, I called the dealer and asked if I should drain and replace it. I was told that the ratings system had changed, not the oil, so if I had been using GTX for 20 years, there was no reason to be concerned about it now.
The only diesel rated oil I found locally was synthetic. Changing 7 quarts of synthetic every 3,000 miles plus a filter gets kind of expensive for a retiree. Just how important to the life of the engine do you consider this to be?
Thanks in advance for your advice.