Cummins ISC Diesel Engine Turbocharger Failure

Cummins ISC Turbocharger Replacement from John Whelan on Vimeo.

This failure occurred without any notice. In the video you can see the nut that loosened off and backed right off of the turbo shaft. Once this happened it caused seizure and a large amount of oil started pumping through the intake system. The turbo bearings are lubricated with pressure engine oil so there's a big mess when this type of failure happens.

The oil did help in a way flowing into the charge air cooler and leaking out a crack in the cooler core. So replacing the charge air cooler was added to the list. Once the turbocharger was replaced with a re-manufactured unit along with the charge air cooler this engine was back in business. It's important to flush out the air piping in case debris got trapped. The steam cleaner does wonders for this type of task.

Preventing this failure would be hard to do since normal preventive maintenance does not involve removing air intake and boost piping for inspection during a service. This would take too much time so the only other clue would be poor boost performance or turbocharger noise audible to the mechanic or driver.

I hope you find this video informative as food for thought. A failure of this kind will happen again undoubtedly somewhere...somehow. It falls under the "how the hell did that happen" category. If you have a comment please state it below. I like to get feedback form readers who have gone through something similar.

 

Replacing Worn Alternator Pulley Serpentine Belt

These are typical pulleys that run a serpentine belt on a Leece Neville alternator. The alternator pulley on the right is the original and is worn on the top edges of the pulley grooves. They are flattened out from belt wear which tells you how durable today's serpentine belts can be.

Of course we launced a campaign to replace the pulleys on the other buses spec'd with the same alternator. Click on the picture above for a closer look (if you could hold these pulleys in your hands you would see the wear much clearer)

The alternator puts out 160 amps so there will be a substantial load on the pulleys and the belt. The engine is a Cummins ISC which uses a tensioner pulley. If this pulley was left on any longer there very well could have been belt slippage eventually. Most mechanics (myself included) would not notice this wear especially during an alternator replacement.

We looked a little closer in this case because of a recurring charging system problem. That's what happens when you look a little deeper into a stubborn mechanical problem.