Home Articles Cummins ISB 6.7 Turbo Failure

Cummins ISB 6.7 Turbo Failure

a cummins isb 6.7 diesel engine in red

The complaint from the operator was a hot running engine and there was a lack of power. This was a red flag that we experienced in the past. The symptoms were exactly the same when we had a failed turbocharger some time ago. The first step was to remove the turbo inlet hose and check the compressor wheel.

After doing so we found oil in the housing caused by a failed oil seal. The compressor shaft was also worn with excessive side play. Most likely the reason the seal failed was too much movement from the shaft running on a worn out bearing. The positive side of this failure is it did not get any worse increasing damage to the turbocharger.

Letting this kind of failure progress causes a big mess with metal fragments getting into the intake and lots of engine oil being pumped into the intake as well. The crankcase breather which is located on top of the valve cover has to be replaced because of the excess oil moving through the system. The engine is a 2009 and was around 6 weeks over the warranty period.

I called the Cummins people and they said I could apply for a policy since the warranty was so close. Thankfully they told me the turbocharger cost would be covered up to 70% if we do the labour. I said “no problem” since the VGT (turbo) is a costly device. The VGT (variable geometry turbocharger) is not your ordinary turbo. It is electronically controlled by the engine computer to change it’s angle on the compressor and turbine wheels to act as the engine exhaust brake and assist heating up the engine during a parked regen.

This turbo design is all Cummins and works great as an exhaust brake. The drivers love these engines because of the hold back potential. So the parts are on order from Cummins and we will be prepping the engine for reassembly. One handy reference we use for repair information is “Quickserve Online”. You can find it easily on the internet to log in and enter the engine serial number.

You’ll find a lot of great information on this site with service and parts info to avoid delays. Having torque specs and “how to” literature really cuts down on repair time. Have you had any interesting experiences with the ISB 6.7? If so comment below and I’ll add some of my feedback. Thank you for reading my post!