If you’re thinking of investing in a Cummins 5.9L engine for your truck, you’re taking a big step. On the plus side, these engines are known for their durability and reliability. On the other hand, nothing is 100 percent sure. Cummins engines are known for experiencing these common problems, which may require costly repairs if neglected.

Fuel Pump Failure

The Cummins 5.9L engine’s most notorious, though not inevitable, problem is fuel pump failure. In particular, the lift pump and injector pump wear out over time. If you experience hard starts, poor engine performance, and stalling, there may be an issue with the fuel pump. Bring it up with your mechanic if those symptoms crop up. Fortunately, you may never have to do that with regular maintenance and inspections! Replacing the factory-installed lift pump with a higher-grade unit may also prevent failure.

Head Gasket Leaks

Don’t blow a gasket over this one! Head gasket leaks are common with the Cummins 5.9L. Leaks may lead to the coolant mixing with oil, which degrades engine performance. If you notice white smoke from the exhaust, an overheating engine, or low coolant levels, something might be up with the head gasket. Take immediate steps by bringing your truck to your mechanic for a review and possible replacement. However, periodic maintenance might help you catch the early signals of head gasket leakage.

Exhaust Manifold Cracking

Cracking up? The exhaust manifold on the Cummins 5.9L engine is prone to cracking because of thermal expansion and contraction. It announces itself through a ticking under the hood and poor engine performance. Make another upgrade here to head off the issue, and replace the old manifold with a high-performance one.

Turbocharger Failures

Turbocharger failures are not uncommon in the Cummins 5.9L engine, especially as you rack up mileage on the road. If you notice a big drop in power, excessive smoke, and odd noises under the hood, the turbocharger might be failing! Regular inspections for wear and tear are good practices; rebuilding or replacing an older turbocharger takes care of business, as well.

Oil Leaks

Every vehicle is apt to spring a leak eventually. Oil leaks are especially common complaints among Cummins 5.9L engine owners, particularly around the valve cover and oil pan. Look for drips and puddles of dirty oil underneath the truck when parked, and note if it seems like you’ve needed to replace the oil more than normal. Periodic inspections should help you catch leaks before or just as they start, letting you know if there’s a need to replace gaskets and seals. Keep your engine clean, and you’ll spot leaks even sooner!

While it’s a great engine, the Cummins 5.9L is not perfect. Still, learning how to recognize and address these issues saves time, money, and your vehicle. If you find a 5.9 Cummins motor for sale, remember the most common Cummins 5.9L engine problems before writing that check!