When the driver called on the 2 way radio he reported that there were huge clouds of smoke pumping out of the exhaust system. My first thought was “shut the thing down”…he was on a bad corner so he had to keep going until there was a safe place to park. This bus is on a run 30 minutes from town so the next decision was to determine if it was worth it to go out and have a look at it and maybe limp it back to town.
At this time the driver was the best resource so I asked as many questions as I could to determine the seriousness of this failure. In the back of my mind I knew it was not a minor problem especially when plumes of white and blue smoke is coming out of the exhaust pipe. Something internally had failed so in order to save the engine from further damage the next step was to call the tow truck.
If you watched the video above you’ll agree calling the hook to get the bus back to town was the logical choice. The exhaust was dripping with engine oil so eventually there would have been an oil pressure issue. We pushed this unit into the shop and began to strip the turbo and exhaust manifold from the engine. A remanufactured turbo from Cummins was ordered along with exhaust manifold gaskets.
The new turbocharger from Cummins had to be adjusted since the housing did not line up with the oil pressure and return ports. There is a snap ring that retains the compressor side casting so it just had to be collapsed a little bit so the housing could be rotated. The air cleaner on the bus was removed to gain better access to the turbo. This is for pusher buses only and makes life much easier to work on the exhaust side of the engine.
After checking into a new charge air cooler from the Thomas dealer the cost and freight shipping from Memphis was astronomical so we are going to send the cooler to the local radiator repair shop. The oil stain you saw in the second video indicates a crack in the cooler core. The radiator shop will be able to repair the core, clean the internal passages and pressure test it to make sure there are no more leaks. I’m hoping it will check out OK considering the alternative.