Sterling Bullet ISB Turbo Repair

imported_John Whelan - August 27, 2016
The video is a quick over view of a repair we are completing on one of our white fleet trucks...It's a Sterling Bullet with a 6.7 Liter ISB Cummins diesel engine. The Cummins code was P2262 which was a mechanical issue with the turbocharger. It would create a back pressure at random which caused a severe loss of power while driving.

This of course was an operator's nightmare especially when pulling a trailer. The code would pop up randomly and in the beginning once the code was reset the problem went away. But most times problems especially mechanical issues don't cure themselves. It came down to the replacement of the turbocharger.

The Cummins VGT is not your average turbo and is designed to do more than one job... much different than the old days of just having to supply a boost of air into the diesel intake system. VGT stands for 'Variable Geometry Turbocharger'. It's designed with a sliding nozzle technology that controls the amount of EGR exhaust gas recirculation back into the intake and the amount of boost that is required under different engine loads.

This extremely accurate method of controlling exhaust and intake volume reduces harmful NOx emissions. The cooled exhaust gas recirculation back into the intake system increases performance and fuel economy. This turbo can adjust for rapid boost at low RPMs and sustain higher boost at increase RPM levels. Not only does this turbo control boost and EGR but also acts as the engine exhaust brake. It's also designed with fewer moving parts reducing mechanical break down.

However in our case we had to install the reman because of a mechanical problem perhaps a sticking turbo vane or something related to the axial movement of the sliding nozzle. The truck is a 2008 so eight years of service out of a turbocharger is considered an excellent life expectancy. They run at insane RPMs and go through extreme heat levels during various speeds and loads so I would compare it to the human heart performing numerous jobs and expected to stick a strict discipline.

Hats off to Cummins getting the job done with reliability worked into their technology. I personally recommend the ISB 6.7 to anyone considering a medium duty vehicle. True ...they are expensive to repair. The reman VGT turbo for our rig cost us 4K but it will most likely get it through to retirement on the auction block but I'm not cancelling out the unforseen circumstances.


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