Author Topic: Cummins ISL 400 Overheating During Climbing  (Read 381 times)

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Offline rlwitt

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Cummins ISL 400 Overheating During Climbing
« on: July 24, 2017, 10:44:47 PM »
2008 Monaco 43' with Cummins ISL 400.  Just started having overheating on this trip starting in June 2017.  Going through NW TX into NM.  All of a sudden temp started climbing to about 215 to 220 then it would drop back to 197 while driving on flat roads.  Air temp around 100.  Started up Raton Pass and temp came up.  Doing all the normal. RPMs up tactics and right at top it went to 225 and engine light came on.  Backed off and exited at RV Park at the pass (planned stop).  Left engine running while checked in.  Temp went back down to 195.  Ended up at Mhc Kenworth shop who changed the thermostat and everything was running cool again.  Continued trip in all flat land until yesterday.  In mountains and temp going back up again.  I'm keeping at 2000 RPM climbing in 4th. Same things I've always done with no temp problems.  Today started getting up to 215/220 range only when climbing.  As soon as I level out it goes back to around 197.  Prior to this trip had some work done on dash AC.  They said they found a hole in the condenser so that's why it wasn't blowing cold air so they put in new one.  It blew cooler for a few weeks and now not cooling much better than before.  Thought?  Is it possible they did something to cause this when they put in condenser?

Offline Brett Wolfe

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Re: Cummins ISL 400 Overheating During Climbing
« Reply #1 on: July 25, 2017, 05:37:39 AM »
First a  question:  Side radiator or rear radiator?  If rear, stacked or sandwiched CAC/radiator?

Brett

Offline rlwitt

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Re: Cummins ISL 400 Overheating During Climbing
« Reply #2 on: July 25, 2017, 06:57:13 AM »
Sorry, meant to put that info in original post.  Side radiator.  Fan is running and was checked when thermostat was replaced.

Also, on Roadmaster frame.
« Last Edit: July 25, 2017, 09:33:52 AM by rlwitt »

Offline Brett Wolfe

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Re: Cummins ISL 400 Overheating During Climbing
« Reply #3 on: July 25, 2017, 10:02:37 AM »
With the side radiator, it is sometimes difficult to determine if the fan is "doing its thing".

Fan speed is not OFF/ON, because even with low coolant temperatures, there has to be air flow through the CAC (Charge Air Cooler).

So, fan goes from LOW to HIGH.  Again sometimes difficult to determine that it is going to high.  With the Monaco product, you might contact Source Engineering for help with troubleshooting fan speed: http://sourcerv.com/conversion

They are ex-Monaco engineers and familiar with this issue.

Brett

Offline rlwitt

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Re: Cummins ISL 400 Overheating During Climbing
« Reply #4 on: July 25, 2017, 01:20:50 PM »
Do you think there is any chance they did something to cause this when they replaced the dash AC condenser?  I know they did something close to the radiator because they left the cover open that swung out once I got on the Interstate.  I was not having any problem with overheating until I had this work done.  Is there any way to disconnect the condenser to see if that makes any difference?

Offline Brett Wolfe

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Re: Cummins ISL 400 Overheating During Climbing
« Reply #5 on: July 25, 2017, 02:36:10 PM »
Sorry, can't speculate as to what they could have done/not done.

No, disconnecting the A/C condenser would probably not be a good idea-- opening up the freon system would result in additional work.

Offline blewis9991

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Re: Cummins ISL 400 Overheating During Climbing
« Reply #6 on: August 02, 2017, 04:46:23 AM »
I had something similar almost exactly the same date in Texas, then New Mexico. I bought a 2000 Safari Continental 330 Cat 3126B, rear radiator. This scenario is different from your but you may find some information.

The outside temperature was about 100+, the coach would run at about 190F - 200F at any speed on level ground. But on a long and not that steep  hill, the temp started climbing until it hit 230 at which point the engine check light came on and the power automatically de-rated. Since this was a 'as-is, where-is' purchase (I flew from Canada to get it sight unseen other than pictures and verbal assurances) it was a heart stopping event.

Here is the tests I did. Hold a ribbon behind the rad to check for air flow. Found there was none, ribbon stayed vertical.
Check the obvious, water coolant for oil  - none, oil for water - none, coolant level - low, added coolant, found a cracked hose on the overflow return. Cut it back and re-installed with new coolant, not water. Checked for outside indications of leaks and found none. So I hoped that the issue was just related to either the radiator plugged externally or internally.

There was no place to flush the radiator at the RV camp site without making a mess of the pad and I didn't have the time or funds to take the unit to someone else to trouble shoot. Just reading on the forums was a better source of information then a crap shoot at some unknown RV or radiator shop. My personal experience is if you do not know the people that will work on the unit personally, you probably will get a $15 per hour lot boy working on the problem under partial supervision of one mechanic overseeing several other jobs. Therefore it was fix it myself, the only option.

This worked as a temporary solution until I could get the unit to San Diego where I had a brother and place to work on things. I bought a patio misting system from Lowes for about $40. Mounted the sprayers in an arch around the fan shroud, clamped the end of the tube off with a vise grip because the end blew off with the pressure, then connected the tube feed to a garden valve (Orbit). The valve was wired to a 24v power supply which plugged into a remote control unit that turned on with a key fob ($9 from Lowes). Then the control unit plugged into a 120v bay receptical. The water source for the sprayer was connect into the water tank system through the garden valve.

So when on a hill and the engine temperature started to climb I could push the button on the fob and turn on the misting system, then by watching the engine monitor and keeping the maximum engine load at under 60% I found that I could maintain the engine temperature at a maximum of 210 - 220F on hills. This used very little water because it was a mist but it kept me going. There is a grade of about 15% I think called the Grape Vine coming from the east to west on Highway 8 with turn outs every mile and radiator water. The coach never had to stop for the 15 mile climb, but i did have to run in 3rd gear at about 25mph at times.

So I know this is maybe irrelevant to your situation but it was a temporary fix and it worked. Once in San Diego I bough some ZEP industrial cleaner from Home Deport and used a garden sprayer to spray the rad from the back of the coach. I tried the front (Bedroom side) but I couldn't get the spray in properly and this is acid based so I didn't want to try doing this from under the coach. Using this product was a mistake and I wouldn't do it again. It says clearly on the container it is NOT for aluminum. I didn't find all the other recommended cleaners so I used this one inadvertently. There was no damage but I wouldn't recommend it again. However I applied this three times with a lot of rinsing each time and there was no leaks or damage. Do not use a high pressure wand, just a garden hose or the fins will bend.

Next tested with the ribbon and there was a lot of air flow. Retested on the way back to Canada on all the hills and the temperature stayed at 190 - 195 on even the steepest hills.

Now as relates to your problems. It could be something the dealership did, or it could be the perfect storm. Your system could be on the edge and needed cleaning. Also I have read that the variable speed fan issue can cause overheating on side mounted rads. Others just turned the fan on to maximum and bypassed the variable speed. If I had this system I would run the fan at maximum speed. As an engineer, I tend to lean to the least risk policy not the optimum best case scenario. I

Offline Brett Wolfe

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Re: Cummins ISL 400 Overheating During Climbing
« Reply #7 on: August 02, 2017, 06:48:59 AM »
blewis9991,

Welcome to the Diesel RV Club.

The VAST majority of the debris obstructing air flow is on the FRONT of the CAC. It can only be cleaned from the front.

And Simple Green Extreme is the proper aluminum-friendly degreaser.

And, be careful with a mister. Unless you use distilled water, you will quickly get mineral deposits that will be impossible to remove.
« Last Edit: August 02, 2017, 07:01:09 AM by Brett Wolfe »

Offline blewis9991

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Re: Cummins ISL 400 Overheating During Climbing
« Reply #8 on: August 02, 2017, 06:48:13 PM »
I agree Bret. I got bumped off before I finished the post and thought it was lost.

I know from your postings the cleaning has to be done from the CAC side but given the circumstances I did what I could. The mister was just a temporary solution in a disastrous circumstance which no options. This may be of use to someone that gets caught a long way from home and in similar circumstance that needs a temporary solution to the overheating problems. I have seen that it is a crap shoot when disadvantaged by shortness of time, and no options with the only RV shops you land in by happenstance. The use of ZEP was a mistake that fortunately didn't go really bad and I would not make the mistake again.

Now the coach is home and there is the possibility to clean this correctly as you have pointed out. What I wanted to post that might of help was that others with a side mounted radiator and the same engine, changed the controller to run full speed all the time. Something to research.

Thanks for your advice, I have searched through your posts in researching my problems and they were a great deal of help.

Robert