Even the most reliable engines have their own particular issues and the 5.9L Cummins is no exception. Although Cummins engines have a reputation for being reliable, there are certain problems that you may encounter. 

Here are 9 common problems with Dodge Ram Cummins turbo diesel and how to fix them.   

5.9L Cummins Fuel Pump, Injection Pump, and Injector Failures

When your fuel pump starts to fail, it may not be immediately apparent, as the injection pump will still be drawing fuel. The injector pump can’t do the job on its own indefinitely, however, and will wear down, resulting in a loss of power. If your engine is difficult to start, or not starting at all, it may be the injection pump. Diagnosing this will require a scan tool.

Whether you need a fuel pump or injection pump, BD Diesel has you covered with the highest quality replacement parts.

5.9L Cummins Cracked Exhaust Manifolds

A cracked exhaust manifold is something that needs to be attended to quickly as it can cause damage to other parts in your engine bay. Hot exhaust gases may melt wires ort even cause combustible parts to ignite. Engine misfires, exhaust smell, poor idling, and loss of power are some of the signs of a cracked manifold.

If the crack is small, visiting a garage that specializes in exhaust systems may save it if they are able to braze or weld it. If not, you will need to replace it.

5.9L Cummins ISB Dead Accelerator Pedal

Pressing down on your accelerator and finding it unresponsive is disconcerting and can be a major cause for concern. It is also not uncommon in Ram Cummins models. The cause may be due to improper calibration, or perhaps a malfunction in the accelerator pedal position sensor (APPS).

An experienced service technician familiar with this problem can likely fix it, but to avoid dealing with the issue in the first place, some things to try include frequent replacement of your fuel filters, repairing loose plugs and wiring, and updating your turbo’s software. 

5.9L Cummins ECM Failure

The engine control module is responsible for hundreds of operations from fuel delivery to engine timing and much more. Several factors can lead to failure, but the most common is component failure. Simply put, the components have a lifespan and once it’s been reached, they can fail. 

The ECM can be repaired if the faulty parts can be replaced. It is also possible that the failure is due to software bugs, so while you may end up replacing it, you may want to check first if repair is an option.

5.9L Cummins Clogged DPF (Diesel Particulate Filter)

A common problem with the Ram Cummins is the DPF becoming clogged. While you will want to replace them with some frequency to help avoid a dead accelerator pedal as mentioned above, you can also try cleaning them yourself, or you can try using a cleaning additive for DPFs, which is a chemical solution added to your fuel tank.

5.9L Cummins Sticking/ Stuck Variable Geometry Turbocharger (VGT)

The variable geometry turbocharger is an effective means of achieving power in different engine conditions, but it is unfortunately also prone to both mechanical and electronic failures. The real problem with the VGT is that the moving parts in the turbo housing become coated with oil, soot, and ash, impeding the movement of the VGT and causing a decrease in performance. A sticking or stuck VGT will normally require disassembly and manual cleaning to restore functionality.

5.9L Cummins Turbocharger Failures

Perhaps the most common failure on the 5.9L Cummins turbo is the oil seals. Worn seals in the centre hub rotating assembly can allow lubricating oil into the intake and exhaust. This can be problematic as the intercooler can be clogged by oil in the intake. The oil can also cause an increase in engine RPM beyond the throttle input. Oil in the exhaust, meanwhile, can damage the oxygen sensors.

Removing the turbo to take it apart and clean it may help, but is not a permanent solution. Most often it will need to be replaced.

5.9L Cummins Head Gasket Failures

This is not the most common issue with the 5.9L as it is under less pressure than the 6.7L. Some signs of failure include white smoke from the tailpipe coolant loss with no visible leak, engine overheating, and bubbling in the radiator and coolant reservoir. 

5.9L Cummins Fuel Dilution

Although fuel dilation is normal and expected to a limited degree, excessive dilution can contaminate the engine oil, reducing oil viscosity. This in turn leads to greater engine wear. You could try a fuel-system cleaner, but in some cases the culprit might be a piece of debris lodged in an injector tip that prevents it from closing. While a fuel-cleaner might help, you may also require a trip to your mechanic. 

While none of these issues are guaranteed to occur, some of them are common enough that you should be aware of them and watch for warning signs. If and when you encounter one of them and require a replacement part, BD Diesel has you covered with high-quality parts that meet and often exceed the original. For more information, contact us today!