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Cummins ISC Diesel Fuel Leak

fuel leak in diesel isc cummins engine

We are working on a Cummins ISC diesel engine which if you did not know is the electronic version of the Cummins C mechanical injection model. They have an 8.3 Liter displacement and run at 250 horsepower.

Diesel fuel leaks are an “out of service” condition and it has to be repaired before going on a run. When diesel gets heated up it emits a very distasteful odor then eventually heavy smoke which is extremely unhealthy to breath. Not good for the young lungs of our student riders.

After some investigating we found a leak underneath the ICV (injection control valve)which does exactly what it’s name says. After removal of the CAPS (Cummins Accumulator Pressure System) head the access is much easier. The plate between the ICV and the CAPS housing had a failed seal.

After contacting Cummins I found out that the plate and seal are not sold separately and we’re stuck buying the complete ICV assy. That’s not surprising but we have a bus down and the cost of the ICV is fraction of the value of the bus overall. If the wheels aren’t turning the bus is not paying for itself so getting it mobile is essential.

The CAPS unit itself is worth over $4,000 to replace and since the year 2000 we have done 4 units in total. Over a 14 year period that really isn’t a lot of money in the big scheme of things when it comes to running a fleet. Not one of these ISC engines have failed on the engine side (pistons and bottom end) except for injector problems and a few failures with cylinder head parts i.e. valve springs.

Once we receive the parts for this repair we’ll go online to “Cummins Quickserve” and get the torque and re-assembly instructions. After the usual running checks and road test it will be ready for action. I’ll be sad when all of these buses are auctioned off in the spring and summer of 2015.

Next year we are buying 11 new conventionals so the 2000 year group of Thomas pusher/Cummins ISC units will be gone. They are running as spare buses this year so they will accumulate very little mileage. It’s kind of a “put out to pasture” scenario like a retired race horse. These buses sit around more than they run on the highways. When we do need them thay always give us dependable service.