Cummins ISL 9L Problems?

[vett]

I currently have almost a year old ISL and looking for some info. I was wondering if any of you guys have had any problems with the engine. Also, what do you think of buy Cummins extended warranty?

[Electra 225]

I think it's a good engine, mine's being good to me. It appears to be reliable overall. Stay up on maintenance.

[Dutch Star Don]

The ISL9, which is also the ISL 360, 400, 425 and 450 has been a mainstay of the Cummins engine lineup for over 15 years. Personally, I think it's the best RV motor on the market and has been so since it came out.

[MuggsnMe]

Good morning
I have been a diesel tech for over 25 years & just wanted to let you know my experience. The CUMMINS isl is a very good engine, at our shop we have had very little major engine issues before the 400,000 mile range. When you get to 400,000-500,000 it will definitely need an over haul. But to more answer your question the issues before that mileage has been water pumps, air compressors, and on a rare occasion an injector or 2. We change the oil & all the filters at 7,000 miles. On all the 5 year extended warranty that we have purchased only a few times they have paid for themselves & they were on the ISLG ( natural gas engine) but not on the ISL 9L. Not to say something can’t happen but it is very rare with proper maintenance. The best advice I can give you, if you can, is to put $200-300 back every month in a separate account so when sometimes does happen you have the cash to help pay for it. But that is your choice, the extended warranty is definitely nice to have but in my opinion doesn’t always pay for itself. Hope this helps.

Bob

[willipaul]

Originally Posted by MuggsnMe

Good morning
We change the oil & all the filters at 7,000 miles.

Bob

there has been much discussion here over the years about recommended maintenance schedules and interpretation over what is best practice....

IMHO, the 15-20K or once a year intervals are just too long...i go every 8-10K, which usually puts me in for two changes a year on average......i do the same on the genset, roughly cutting the recommended intervals in half....

now, i imagine that a commercial fleet, that gets worked harder, and abused, far more than an RV, needs a more frequent heavy service interval, but RV's get worked hard as well....mountains, headwinds, stop and go traffic, short cycling....they all take their toll....

it's nice to see a tech post up an example of a more frequent interval....

[vett]

thank you all for your help

[lwmcguire]

Originally Posted by Dutch Star Don

The ISL9, which is also the ISL 360, 400, 425 and 450 has been a mainstay of the Cummins engine lineup for over 15 years. Personally, I think it's the best RV motor on the market and has been so since it came out.

Statistics show it is one of the best engines ever designed

[AE Wanderer]

I have a 425HP ISL. We have had 2 problems. 1) water pump went out. This could happen to any engine. 2) The EGR cooler went out. This is a known ISL problem. Cummins no longer offers the ISL EGR cooler. In its place they offer the ISX cooler and an adapter kit. Plan on $4.5K if unit has an EGR cooler and it has not been replaced.

[timjet]

Originally Posted by willipaul

there has been much discussion here over the years about recommended maintenance schedules and interpretation over what is best practice....

IMHO, the 15-20K or once a year intervals are just too long...i go every 8-10K, which usually puts me in for two changes a year on average.....snip

Why do you feel a more frequent mx interval (for example 15,000 mile/annual oil change interval) than Cummins recommends is necessary or prudent?
I believe the annual was added for infrequent users.

Just asking.

[willipaul]

Originally Posted by timjet

Why do you feel a more frequent mx interval (for example 15,000 mile/annual oil change interval) than Cummins recommends is necessary or prudent?
I believe the annual was added for infrequent users.

Just asking.

modern diesels with complex emissions systems are hard on fluids.....

it gives me comfort to cut intervals and change out fluids of all kinds on the earlier side.....

i think manufacturer suggested service intervals take into account other factors, such as total cost of ownership statistics, not just fluid longevity, in any given application.....and i think the total cost of ownership concept is particularly relevant with recreational applications.....

anyways, i do what i can afford and what makes me feel good....with the usual JMHO and YMMV disclaimers....

[MuggsnMe]

Hi all
I am going to try & help with this without going to far in depth.
Let’s start with the oil & filters
When the engine goes into regen, the exhaust temp will exceed 1000 degrees Fahrenheit (don’t know the cel. equivalent, lol). With this temp it will break down the oil lubricity causing more friction on the internal components, which will cause more heat, more heat causes more wear, more wear causes engine rebuild soon than needed. Also when an engine is started from cold (sitting overnight) it creates condensation that the oil picks up & the filters capture. It also can create more carbon build up. As the engine gets warm the condensation dissipates. Also dirt molecules & carbon get picked up in the oil & is captured in the filters. My opinion why CUMMINS has their oil change intervals as high as they are is because over the road trucks don’t shut down as often & if they did a 7,000 mile oil change it would be done every 3 weeks for them. This is just my opinion, I am not trying to change others that do it their way.
Next, Fuel filters
I am sure nobody goes to the same place all the time & fills up their tank, so.
I would rather change the fuel filter more often, than have the possibility of getting any dirt in the fuel system... if a small piece of dirt gets to the injectors it can cause an uneven spray pattern, like a direct spray instead of a mist. This will cause a hole in the top of the piston or on the cylinder wall. I have seen this happen, no joke! Keeping the fuel system clean will also help with the internal part of the pump.
Next the air filter
I would agree that it doesn’t need changed every 7,000 miles but it should be taken out & looked at & cleaned from the inside out. I have seen it on a few occasions that the air filter started to collapse & was caught in time before any damage. Also it should be rotated so the same filtration area on the filter is not always lined up with the outside air intake port.
Next water filter
If the coolant is tested for nitrate this will tell you the level & if the coolant filter needs replaced. The filters have a capsule it in for a time release to keep the nitrate level adequate. The nitrate protects the metals from any acids eating away at it & also helps the seals.
I think i might of went a little overboard with my explanation LOL
But this is just my opinion & others may vary.
So back to the original post about warranty, if these steps are followed a major engine overhaul can substantially be avoided in general, just not always, freak things do happen. With these steps taken other components like turbo, injectors, air compressor head, etc..can last a lot longer.
Sorry for such a long read, wanted to keep it short but just got too involved in the explanation.
A strong preventative maintenance program can go a long ways towards preventing major mechanical issues, thus giving you more time to enjoy the rv lifestyle.
Again this is not intended to start an argument I just wanted to share my views & opinions. Thanks

Bob

[timjet]

Bob, does the regen process increase the engine temp? I thought it increases the DPF temp to burn off contaminants, but not the internal temp of the eng.

I guess I'm lucky in the sense that my '06 build engine does not have a lot of the emission controls later engines have. I do change the CCV filter every other year according to Cummins recommendations.

Also modern diesel oil filters have become much better at filtering contaminants. I believe they have a double filtration process that is much more efficient at keeping the oil clean than older gen filters, or even filters on your car.

Bob makes a good point of rotating the air filter, I had not thought of that.

[lwmcguire]

Sure can't rotate my air filter

My engine temperature stays the same during regeneration

Filter cake builds up on filters making them more efficient

Filters are many times better today than the original Diesel filters

Oil test continues to show short oil changes aren't necessary

Everyone has their comfort zones

I change the fluids based on data only, not opinions

[MuggsnMe]

Tim
the regen will increase the engine temp through the coolant process & exhaust manifold.
the exhaust pipes get hot which in return will heat up the complete exhaust system, exhaust manifold, egr cooler, etc. Now that doesn't mean the the engine is going to get to 1000 degrees. it is just more heat that gets circulated thru the other components in the exhaust system. hope this help explain it better.
As far as the oil filters go you are correct technology has gotten better over the years & so has the oil. I am still old school & teaching an old dog new ideas is hard for me. Not to say you are wrong on your ideas.
Changing your breather filter is very good practice a lot of people don't think of that. Same as the air filter, it gets over looked as well. I hope my response has given some light on this & has help out some of you with any question that you might have been thinking about. I do not own a DP I have a Tiffen open road gas but I will be retiring in 2 years & have been looking at the Dutch Star, we just love the looks of this coach, that is my goal. All the info on this forum has been fantastic for my wife & I. If their is any negative I can say is that all the info on this forum has been so overwhelming positive that I do not want to look at any other manufacture other that Newmar LOL. We cant wait to possible meet some of you in person someday. Safe travels!!
MERRY CHRISTMAS TO ALL & HAPPY NEW YEAR!!!