This is a 2008 Mercedes MBE 900 Diesel Engine that has been sitting for over a year now. It had a major issue with losing engine coolant every time the bus (Thomas HDX Pusher Bus) climbed a grade under load. The coolant would blow out of the coolant fill tank (surge tank) a gallon at a time. It was thought at first that the EGR cooler was at fault but soon it was confirmed that the engine block had a crack in one of the engine cylinders.
This causes a problem since 400 psi is developed in each cylinder during compression…. this force would get in to the coolant system causing a spike in the coolant pressure exceeding the 20 psi rad cap pressure and blowing out the surge tank quickly. The alarms and dash lights came on every time this happened to protect the engine from over heating.
After disassembling the engine and testing the cylinder head this is how it sits today. The cost is excessive with a 35,000 dollar bill to replace the complete engine. There was also a 10,000 dollar core that we would lose due to the crack in the block. At 45,000 dollars plus tax and duty and shipping from the U.S. We decided to park and apply for a new bus replacement from the ministry of transport.
There was no luck looking for a used engine block since this bus was a 2008 which is emission controlled. The block is cast to accommodate emission add on parts. There were plenty of older pre-emission engine blocks but nothing available for 2008. Now as you can see in the video this poor old dead bus is parked in the middle of our yard getting stripped of parts that we use on other running buses. We have no clue what will become of this scrap metal school bus but I imagine someone will claim it.
It will definitely get the best working parts removed by us which could run in the thousands of dollars. This is the first Mercedes diesel engine in the fleet that suffered this failure and over all these engines have performed well otherwise. Daimler stopped manufacturing these models I believe back in 2010 simply because they could not keep up to emission requirements. If you are looking into a Mercedes MBE 900 diesel engine I recommend getting one 2006 or older. These older models are much more reliable than the emission controlled diesels 2007 and newer.