While our truck was already in for service at Thayer, we decided to ask for an in-depth checkout of all of the engine, cooling and drivetrain components. The technician is a Duramax diesel owner and fellow RV’er, so he knows the engine and the lifestyle. He found the probable cause of the failure of the turbocharging system! When the new parts were installed on the engine, he connected up his electronics and took the truck out for a test drive before calling us to pick it up. The tests quickly indicated that the air/fuel ratio was not correct, not even close. So he brought the truck back in and found a fairly large crack in the back/underside of the “Airbox”, and that has its own air filter, the crack was after the filtering thus allowing more air in then should be. It is unclear when the crack occurred, but it was definitely broken and has to be repaired.
He took the airbox off and as a temp fix, epoxyed the crack and some extra duct tape, re-assembled it and took it for another drive. All engine readings returned to normal then! So he called and gave me his recommendations. He combed through Chevrolet’s maintenance records comparing when service was performed vs what should have been performed. It seems my local dealer hasn’t been advising me very well on things. So we added several other things to the list, but when it gets returned to us, we will have a very reliable truck back and it will last another 10 years easily.
When we pick the truck up on Friday, we will hook up the truck and he will plug in his diagnostics unit and we will test everything under a real load. If all goes well, we will be back Friday afternoon.
Thank you, Thayer!