Cummins Engine Repair - ISB Model

Cummins Engine Repair on a 2002 Thomas Freightliner School Bus. The head gasket was leaking coolant from the right front corner. The first step is to unhook the battery and drain the coolant.
The Turbocharger [pictured] can be removed as a complete assembly attached to the exhaust manifold. The fuel lines are removed from the opposite side.


The Cummins 24 valve turbo diesel has 2 intake valves and 2 exhaust valves for each cylinder. The parts displayed here have been cleaned and inspected for pitting, hard surface wear and corrosion [head bolts]. Head bolts are measured for length, with a special guage provided by Cummins [usually comes with the head gasket kit].


The cylinder head itself weighs approxiamately 80 lbs. [3 Mechanics removed the head off the block manually and it's a clumsy operation!]
Here I'm using the hydraulic hoist to install the head, the only problem we encountered was the reach was not long enough on the hoist boom so I removed the front wheel to enable rolling the hoist into the engine compartment further. [An overhead hoist would be perfect for this job!]

Cummins Engine Repair involves cleaning and inspecting, especially when it comes to the block surface. Look for any cylinder scoring and cracks then run a straight edge on the block surface where only a few thousands of an inch wear is allowed. Use a .003 in. feeler guage to check the block wear.




Removing the injectors is easy once the fuel connector tubes inside the head are removed [Below]. The injectors have hold downs on top that have 2 fasteners, when removed the injector has a threaded hole on top that can be used to pull the injector out which is held in by an o-ring.
NOTE: Remove injectors before removing cylinder head, the injector tips protrude past the head surface.


The fuel connectors in the Cummins 24 valve turbo diesel have an o-ring seal and connect the fuel between the fuel injector lines and the injectors. They are tapered and have a machine fit into the injector body. The injector hold downs only install one way and index the injector in the head bore so the connector tube aligns with the injector.



I hope this basic overview has helped you get more aquainted with Cummins Engine Repair

More To Come!

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