After losing a turbo, Chapman Chevrolet in Reno Nevada told me that I had a bad accumulation of oil on the fins. They told me to never use full synthetic oil only regular 15/40 ! My truck only has 104,000 miles on it... WHAT IS THE TRUE STORY ON SYNTHETIC VS REGULAR 15/40?

 

Sounds like you had a turbo problem leading to the accumulation of oil in the compressor housing. Syn-oil ( for Diesels) isn't gonna cause that issue. My neighbor, across from me, has been using syn-oil since he bought his '05 Dmax, and he has over 206k on his, without issue. Ive been using Rotella T-6 or Mobil-1 syn-oil in my 06 cummins since new, and I have 187k on mine with out ANY issues whatsoever. In fact, Ive used syn-oil in all my vehicles, past and present, turboed or supercharged without negative issues.

 

Why would the Chev dealer suggest that statement then?

 

Why would the Chev dealer suggest that statement then?

 

Take it to another chevy dealer, and you will likely get a different answer. You never know when a turbo is gonna crap out. Are you the original owner of that truck? Has it ever been abused, run hard all of its life, whats the history? I bought a 2002 D-max brand new, back in 02. 2 years later my turbo crapped out. I was pulling my travel trailer through Phoenix, AZ. Luckily the warranty took care of that. Anyway, I had just over 14k miles on the truck. Later traded it in for a new 06 Dodge cummins which still has the original turbo, at 187k. Turbos will fail, either suddenly, or over time as they exhibit signs of impending failure. Very doubtful that syn-oil will cause turbo failure.