The Cummins diesel is without any doubt a longevity engine. If you service it properly, the engine can last 500,000 to a million miles between teardowns. Peripherals such as Cummins injectors, the turbocharger, as well as the fuel pump, however, can wear out or fail much earlier.
A properly maintained fuel system can keep the Cummins injectors going for 250,000 miles or even more. Well maintained injectors will deliver good performance as well as fuel efficiency without showing any signs of spray pattern issues, fuel surging or leakage.
Long injector life depends upon a number of factors, including adequate fuel supply, quality fuel filtration as well as clean injector components. Apart from the routine fuel filter changes, you need to periodically clean the fuel system if you want your Cummins injectors to last long. Purging the high pressure pump and injectors will help to maintain peak performance and ensure reliability.
When you start seeing symptoms of wear, leakage or a fault code, it is an indicator of injector trouble; it would be a good idea to bench test the Cummins injectors on a Cummins test stand. If pilot injection, full load flow or the volume of return fuel fails during this test, it is a clear sign that the injector needs precision rebuilding or replacement with a brand new unit.
A lot of shops sell new or remanufactured injector, so you should not have a hard time finding the right one for your needs. A full set of new Cummins injectors may also provide a design upgrade, perhaps better durability or performance compared the original injectors. In any case, a full set of new Cummins injectors will be costly, but they will be worth the money.