5 Common Cummins X15 Problems (Troubleshooting)

cummins x15 problems
cummins x15 problems

Everybody loves to go on holiday. Some people love it so much they spend a significant amount of money purchasing a holiday home somewhere or a holiday home on wheels in the form of a motorhome or RV.

For many, this offers them numerous benefits – convenience, comfort while travelling, space for the whole family to get together, and the opportunity to get away far more regularly or for longer trips, taking time to truly explore.

Although it can be an expensive initial outlay, the benefit is being able to have numerous holidays without having to break the bank each time. Having invested in a vehicle such as this, however, it is crucial that you take proper time to keep it well maintained. This will limit the number of issues you might have whilst out on the road.

Preventative maintenance can shield you from a number of issues, especially when it comes to your engine, which is arguably the most important component of your vehicle. Keep your fluid levels topped up, regularly check the condition of the oil in your engine and change it whenever you notice it’s starting to look dirty, dark or thicker than usual. Check hoses and connections regularly. Basically, get to know your engine so that you can quickly spot when something isn’t quite right.

One of the most widely fitted engines within the RV and motorhome market is the Cummins X15. Whilst it does have numerous benefits and advantages which make it really popular – it has good performance overall – but it also has some known issues.

In this article, we will talk about some of the most common problems, how to identify them, and what your next step should be if you think you are suffering one of these problems.

Cummins X15 Problems

1. Fuel filters clogging

Fuel filters clogging

One of the most common issues with the Cummins X15 is that their fuel filters clog up much quicker than is usual. This is particularly prevalent for those regularly travelling to, or living in, colder climates. Although replacing the filters is a relatively straightforward job and not really a problem as a one-off, this is not ideal if the issue keeps happening.

Residual particulate matter can cause the clogging, therefore there is always the chance that the issue might be with the standard of fuel you are using; a dirty batch as a one off or refuelling at an unfamiliar location where you don’t know the quality of fuel on offer can create problems. However, if you are confident there is not an issue with the fuel and the problem keeps happening, then you need to find a more permanent solution.

One way to try and resolve this is to replace the filters with a larger gauge filter. However, you should be aware that this could cause other problems and should only ever be done under advisement from an expert. Many users have reported that, after seeking advice, they have replaced the factory fitted 10-micron filter with either a 20-micron or 30-micron filter and this has eliminated their problem completely.

If you do live in a colder climate this may not work for you. By all means try it, but if it doesn’t resolve the problem then you could also consider having a heated filter fitted, possibly alongside a tank heater, or just a tank heater on its own. Although this is quite a costly fix, it is the recommended fix from the company and therefore should eliminate the problem.

2. Camshaft issues

Camshaft issues

Another common fault is with the camshafts. In some models, the rocker arms stop some components getting adequate oil. Then, because they are not fully lubricated, this makes them stick and hit the camshaft. Over time, these become flattened. Unfortunately, it is difficult to diagnose.

However, if you have experienced a loss in performance this is worth investigating further to see if it is the cause. If you lack the mechanical knowledge to check yourself, you can take it to a workshop and explain your suspicions to the mechanic as this will give them a good starting point.

3. Knocking noise

Knocking noise

This issue is not just specific to this make of engine; however, it is a common issue and therefore is worth including here. If you notice knocking noises coming from your engine bay, there is a good chance your engine oil needs a top up.

In some cases, it may be in need of a complete oil change. It’s advisable to always carry a little extra engine oil with you. However, if you don’t have any, then you should purchase some as soon as possible. Continuing to drive with low levels of engine oil can cause significant damage.

4. ERG Valve leaks

ERG Valve leaks

Like a great many engines that are fitted with an EGR (exhaust gas recirculation) system, sometimes problems can be caused by a leaky valve. Whilst this may not seem a significant problem, the problem can compound over time and cause big performance issues.

This is another issue that can be difficult to diagnose, but there are some giveaway signs that this may be affecting you. If you notice your coolant levels being consumed much quicker than usual, you have fluctuating levels of coolant consumption that don’t relate to the conditions, or you have white residue indicating burnt coolant, then you need to take your vehicle to a professional for further investigation.

5. Cylinder liners

Cylinder liners

The Cummins X15 is a mid-stock steel cylinder liner equipped engine. In other words, there is a cylinder liner that is put into the engine at the factory. It is supported halfway down the liner.

If a piston seizes, then it is possible for the cylinder liner to get broken at the bottom. Then, if the connecting rod or piston comes loose, they could detach altogether and destroy the engine – so it’s really important to spot any issues in this area quickly.

Typical indicators of problems in this area are as follows: a drop in pressure, leaking coolant, and an overheating engine block. If you spot any of these problems, we recommend that you take your vehicle for inspection by a professional as soon as possible and avoid driving it in the meantime.

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