High Performance Diesel Engines
Burned Turbochargers, there is a reason to have a good working pyrometer, with the thermocouple in the exhaust manifold and a turbo boost gauge, and know what they read and mean. On April 28th, I returned a phone call to an older gentleman, who was, in fact, three years older than me, that sent us a turbocharger off of a 12.7 DD4 Detroit looking for a warranty. The failure on the turbocharger was a burned turbine housing and .025 endplay on the wheel and shaft when there should be no more than .012 endplay. My first question to the owner was, "do you have a pyrometer (EGT) gauge" and he replied, "no, but my truck doesn't run hot." I asked, "how do you know? It is impossible to know the exhaust gas temperature on the older engines with a pyrometer." He did say the engine produces 25 to 27 psi of boost, which should be 30 psi for a 500 Detroit 12.7 liter. At least he has a turbo boost gauge. Now here is where the problem lies, the rear gears are 2.91, turning 24.5 tall rubber, and a double over 13-speed transmission. He drives this truck, a 2003 Freightliner Columbia, single air filter under the hood, at 70 mph at 1200 RPM. The DD3 and 4 12.7 liter Detroits need to be at 1400 RPM and higher, especially at 70 miles per hour. Running this low RPM will produce excessive exhaust gas temperature, which in turn fried the center section of the turbine housing. He has an air filter restriction, which caused the thrust washer to wear out, giving the wheel and shaft .025 end play. With that much end play, the compressor wheel, fresh airside, has hit the compressor housing. The air filter could be dirty or could have gotten wet from driving through a downpour. If the air filter is paper and gets wet, it must be replaced soon. The wet air filter will cause excessive wear on the thrust washer and pull oil past the seal and into the charge air cooler.
As you can see in the pictures, the turbine housing has been burned from excessive heat and excessive end play. Needless to say, there is NO warranty on this turbocharger. I can save this turbocharger by installing a bearing and seal kit and a new or used turbine housing. Excessive soot and carbon cause the variable vanes in a VGT turbocharger to look up, thus rendering the turbo useless.
This turbocharger is off of an International 530 engine. The rust on the outside of this turbo shows that the truck sat in the grass for extended periods of time. Soil and grass hold moisture and will cause excessive rust in the northeast. If the truck owner had been running the Max Mileage Fuel Borne Catalyst in his fuel, the truck would still be up and running. Now he needs to spend $2900.00 on a new turbocharger. As we say, it costs 1 cent per mile to run the catalyst; however, it will save 6 cents per mile in maintenance.
Written by: Bruce Mallinson, Pittsburgh Power, 3600 S. Noah Dr., Saxonburg, PA, 16056 Phone (724) 360-4080