Cummins ISX Years To Avoid (2004-2007 ISX Cummins Problems)
Successors are not always good. When you have to replace something that is good or excellent, the next invention may not be so good. This is the case with the Cummins ISX engine. It was the successor to the N14 but things did not work out so well for Cummins
It may come with 600 HP and 2000 lb-ft of torque but the ISX engine made by Cummins is not the ideal engine. This motor came with a lot of flaws that ruined its reign as a top Cummins engine option. It was a duel fuel engine but that did not improve its chances of being excellent.
To learn more about this engine and why the 2004 to 2007 models are motors to avoid, just keep reading our article. It gives you the information you want to know about so you can make a good buying decision. Not all RVs have this motor inside
Cummins ISX Problems 101
Cummins ISX Production Years
There have been many renditions of this motor and it all started with the EPA. This government agency implemented new rules and those rules made the N14 obsolete. In its place and in 2001, Cummins decided to make the ISX.
This model lasted until 2010 when new regulations were implemented. But the ISX series remained with some major upgrades. According to our research, the ISX signature series has been in the process of being phased out.
This phasing out started in 2016, 2017, and 2018 depending on the motor version you have in your RV. Whether it is still in production or not remains to be seen. Cummins has gone to the X 15, the X 12, & the ISX 12N.
So, yes, the ISX engine is still in production at a slightly reduced capacity. The new generation of diesel motors made by Cummins is supposed to meet all modern EPA and other standards.
Many people still would like to have the N14 motor back. It was supposed to be a great engine. People still talk about it today and some owners still have it under the hood of their RVs.
Best Year Cummins ISX
According to some owners, the 2002 model was the best year for the ISX. The reason given was that this engine did not come with all the expensive repair parts like- Pre EGR ISX, no EGR, no VGT, no SCR/DEF/DPF.
It seems that once the EPA got involved, it was impossible to build top engines due to all the emission control devices that had to be placed on different motors. The ISX suffered because of these mandatory additions.
Someone mentioned that there have been 50 recalls to the ISX over the years. We are not sure of that number or how many applied to the 2002 as we have been only able to confirm 4 of them. Those 4 were for the 2010 forward model years. They also had to do with emission issues.
What we have been able to confirm is that these recalls took place from 2016 onward. That helps bolster the case that the 2002 year is the best model year for this engine.
But the best label is subjective and you may have a different opinion or know someone who does. That is okay or as long as the engine does its job, it is the best engine and model year.
Cummins ISX Years To Avoid
This too is very subjective and a matter of experience. Some people think the 2004-05 motors are the best and better than the 2002-04 engines. Others think the reverse.
To be honest, we did not see anyone really talking about the best and worst years for this engine. They talked about the motor which had 600 HP or the 53 block and other features.
Owners are stating that those engines caused the most problems while others have said the 600 HP was a great engine. Still, others did not like the 2002 engine because the VP44 was supposed to be junk.
If you do not know what a 53 block is, this is the block that was badly cast by Cummins and it would tend to crack on you. The number 53 is included in that casting and it is supposed to be behind the driver’s wheel well.
This is the way our research went. There is no definitive labeling of these years are the years to avoid. Every production line in every industry and product will have flawed products. But those flaws do not ruin the rest of the production line.
2004-2007 ISX Cummins Problems
There are several common problems that have arisen over the years. here are some that may not be limited to those specific years of production:
1. Turbocharger issues- Prone to turbo lag which is defined as slow throttle response. This issue was or is caused by lubrication problems, clogged filters, and reduced fuel intake. This issue has been known to create engine damage. The earlier you identified the source, the better it is for the engine
2. EGR issues- this part’s problem centers more n the EGR valve than any other part in that emission control system. If this valve fails, then you will see more nitrogen oxide emissions and some performance-related problems. Signs this is the problem is engine performance problems, check engine alert, and rough idle.
3. Faulty Camshafts- this is caused by faulty rocker arms. These rocker arms become faulty when they do not get enough lubrication to do their job. Once that happens these arms flatten the cam lobes which damages your engine. They can also cause your engine to blow up.
4. Timing wedge issues- This part is located between the cam gears and its job is to redirect the oil as it goes through the camshaft. When these parts fail it could lead to delays in opening the valves. The fix for this is changing your oil filter.
5. Cylinder liner issues- The liners are capable of cracking and falling in the borehole. When this happens your engine is vulnerable to a lot of damage. The cause of this cracking is due to the following issues:
- Incorrect installation
- Erosion and corrosion
- Presence of foreign bodies in its combustion space
- Poor cooling
- Improperly fit piston(s)
The signs of this problem are a drop in pressure, coolant leaking, or overheating of the engine.
Cummins ISX12 Problems
The following issues may not be limited to the ISX 12 either. It is a diesel engine thus it will have related problems that come with all diesel motors. here are some of them:
1. Engine not starting or hard to start:
- low engine pressure
- low fuel pressure
- low cranking speed
- lack of fuel supply
- the fuel quality is low
2. Idle is rough or at low RPM:
The sources above apply here as well as the following additions:
- flawed fuel injector
- air intake problems
- faulty airflow sensor
3. lack of power:
- dirty fuel filter
- loose throttle linkage
- lack of air intake
- faulty fuel injectors
4. Black smoke:
- faulty fuel injectors
- flawed injector pump problems
- dirty air cleaner
- flawed intercooler or turbo
- cylinder head problems
- clogged valves
5. White smoke:
- engine & pump timing off
- low engine compression
- water or oil in the fuel
6. Blue smoke:
- worn-out piston rings or cylinders
- faulty valves or stem seals
- too much engine oil in the oil tank
- faulty lift pump or injector pump
There may be more and some of the common problems for the 2004 to 2007 models are listed for this motor as well. Most places do not list the exact year but simply say common problems for Cummins diesel engines.
You may experience some of these issues or you may experience the ‘eating of the valve’ problem that some owners have had trouble with.
2013 Cummins ISX15 Problems
This motor is going to experience a lot of the same common problems as the previous two versions have experienced. Every web page we looked at did not differentiate between model years.
Instead, they just listed a few common problems and attributed those problems to all ISX engine models. Those lists do not vary. They place the exact same parts in their lists.
Some owners have mentioned individual issues, for example, no regen below 330f. The possible source may be a dirty IMAP or the weather conditions are wreaking havoc with the sensors.
Or the airline from the control valve has a hole in it. But no one has linked to any report that states this is a common problem experienced by a large group of ISX15 owners.
Cummins ISX Reviews
One of the first things you read is the praises for the N14. With this much praise heaped on an engine you are supposed to be replacing, it is hard to match up.
One reviewer said that this model is a workhorse of an engine but it is no N14. it has its issues. Some people do not like the model that came with the 600 HP. They thought it under performed and had too many flaws. The early models of that motor were the ones that ‘ate the valves.’
Then there are those owners who liked the pre-2004 version because it did not have all the pollution control devices attached to it. The other side of the coin had owners praising the power that was built into this motor.
They also liked the fuel efficiency which was said to be better than the N14’s performance. It is a good engine as there are still millions of them on the road today that do not experience the problems mentioned above.
Is The Cummins ISX15 a Good Engine?
It is a matter of opinion. Different owners get different results and some are pleased while others are not. Then with the different versions that have been made, it will depend on the version if it is good or not.
Overall and generally, the ISX is said to be a good motor to have powering your RV. In fact, every major Class 8 truck manufacturer uses the ISX line. That says how good it can be.
Unfortunately, not every motor made on the production line will be great. There will be lemons from time to time but those flawed motors do not speak for all of them. The power is there and it is said to be a good tow motor.
We will leave it up to you and your judgment/experience if you think this motor is good or not. It does have the evidence proving that it is.
Are Cummins ISX Engines Good?
What has been said in the last section can and does apply to this generalization. The evidence is there that the Cummins ISX is a good engine. However, according to many owners, it is not as good as the N14 was.
That is a high standard to try to live up to and replicate, especially when the N14 was not hampered by a lot of pollution control devices. Those devices do influence performance and can make all the difference when you are replacing a superior motor. Some people call the N14 legendary.
The ISX engine does hold its own even with those common problems. You just have to do regular maintenance and watch out for the warning signs to protect the engine and help it last a long time.
How Many Miles is a Cummins ISX Good For?
500,000 miles is one figure that has been mentioned. The owner has that many miles on it already and is hoping to get about another 250,000 miles on it before he has to rebuild or replace it.
Another owner had to overhaul his at 950,000 miles and is now over the 1,500,000 mile mark. That is an additional 600,000 miles after the rebuild. What this tells you is that if you take care of the engine it should last you a very long time.
Some parts, like the 3 head and 2 head pumps, may only last to about 400,000 miles but they are very expensive to fix costing over $6,000. The type of longevity you get depends on your driving situation and how rough or kind it is to the motor.
Each owner should get a different result and do not be surprised if yours does not last as long as the next guy’s.
Cummins ISX Life Expectancy
This is as subjective as how many miles does a Cummins go. The reason we say that is if you only drive 20,000 miles a year, it is possible to have the engine last 30 years.
If you drive 100,000 miles a year, you may only get 6 to 10 years of life out of the motor. Also, how well you maintain the motor and how you treat it will influence how long it will last.
Badly maintained or treated roughly should shorten the engine’s lifespan considerably. If you are overloading your RV, then do not expect the engine to last a very long time no matter how few miles you drive each year.
When you have a good model, the engine could last up to 1,000,000 with ease. It will all depend on you and how good the parts are.
What Year Did Cummins ISX Get EGR?
2002 was the last model year that was produced without an EGR. That means that 2003 was the first year Cummins installed that part on its ISX diesel engines.
There may have been some late 2002s that received the EGR but that is doubtful. What this means is that you will not have any EGR problems on any pre-2002 motor. That is one common problem you can cross off the list.
The pre-2003 models were a lot better in some people’s minds. That is because they see the difference in performance between the pre and post-2003 eras.
Those engines probably performed pretty close to the N14 models which are said to be one of the best engines Cummins made. EPA regulations have a way of ruining top engines and making them more expensive and complicated to repair yourself.
Some Final Words
Improvements are not always turn out to be a good thing. One reason for this is all the new equipment that has to be put on diesel motors. While the ISX is a good motor to have, and it will last for a very long time under proper care.
However, there are some common problems that try to undermine that longevity and make it a common motor that won’t last. Just make sure to take care of the engine and you should be fine. It is hard to beat a Cummins diesel.
