Cummins ISL 400 Overheating

[turbogrampa]

I have posted before with regard to this common problem and have received many solutions. I have pressure washed the stacked rad,,changed the thermostat and now have replaced the temperature sensor with one direct from Cummins, On a trial run the temp. gauge never moved. I took the sensor out and checked the resistance at room temp, It showed 7.5x1000 then out it in boiling water and resistance went down so low I could not read it on my meter. So I think the sensor is good.
Checked the wires to the sensor and one showed going to ground and the other about the same as the sensor. ANYONE have an idea as to what is going on??
Temp. gauge reads about 200-210 running down the road and climbs on all the grades. the alarm goes off around 225-230 the ECM thinks that it is really overheating ,but if I leave the rad. cap off it does not boilover???
Also changed the coolant with the long life antifreeze and 3 bottles of water wetter !!!
Any and all help will be appreciated, Thanks in advance.

[TR4]

I would start here. Get one of these,

https://www.harborfreight.com/121-in...ter-63985.html

Point it at the thermostat housing and confirm the temperature reading after reaching operating temperature.

Bill

[Dutch Star Don]

I owned a 2005 Monaco Diplomat with the 400 ISL. The day we bought it, I drove it home from Fresno California to Los Angeles. Part of that trip includes climbing the large grade into Los Angeles (Grapevine). There is a gradual grade starting about 10 miles before. As I started up that grade, I could hear a screeching from the dash that slowly turned into an alarm. I pulled the coach over and called Monaco. They told me that alarm was something added by Monaco and was useless. It was located behind the instrument pane and could be accessed from the dash cap. I was told to disconnect it, which I did. They also explained (this was my first DP) that if the coach was actually getting hot, the Cummins computer would derate the coach, through some dash codes and tell me there was an issue. Once I disconnected that alarm, I never had another issue over 10 years.

Your second issue....the dash gauge. Monaco had the worse dash gauges. If yours is like all the others, the transmission gauge never moves more than maybe a 1/4". I'm guessing your having an issue with the actual temp gauge.

There is a program made by Silverleaf, called the VMSpc program. The program reads EVERYTHING that the Cummins ECM computer reads. The program is free to download from their website to a laptop, but the cable that connects your Jport (OBDII port on motor homes) to the laptop is about $300.00. The program will tell you EXACTLY what temps you're running from trans to coolant to oil. The Cummins ECM does not look at EGR temps and is not connected to the exhaust. It looks at manifold temp for checking overheating. It may be worth your time and energy to buy the cable and connect to a laptop and REALLY see what temps you're running. I've been running the VMSpc on a small 8" laptop for over ten years now. I don't start or drive my coach without the laptop on.

Here is a photo of my VMSpc program running on my coach. I like running a rolling MPG gauge, oil pressure, coolant temp, trans gear, turbo boost, voltage, speed, three odometers and rolling HP and Torque.

[ronster]

Scan gage D,about 125,very small,does much of silverleaf does.If side radiator does the fan control work correctly?

[Gary RVRoamer]

Need more information to make any guesses. Is the radiator fan running and is it fixed or variable speed? Is the coolant actually over heated? Just running with the radiator cap off doesn't prove much, and the system doesn't work properly when not under pressure anyway.


Please include the year/make/model info, at least for the chassis. Cooling systems vary by both chassis manufacturer and sometimes the even chassis model/configuration.

[YC1]

Call Source Engineering and tell them your issue. I bet they have a solution.

[turbogrampa]

Originally Posted by TR4

I would start here. Get one of these,

https://www.harborfreight.com/121-in...ter-63985.html

Point it at the thermostat housing and confirm the temperature reading after reaching operating temperature.

Bill

Thanks Bill, That was the first thing I did. Housing running 215f, rad. too.

[turbogrampa]

Thanks Bill,
I all ready had one and that was the first thing I checked.
215f @ housing.
Rad. also about 212/217 depending where you read it.

[turbogrampa]

Originally Posted by Gary RVRoamer

Need more information to make any guesses. Is the radiator fan running and is it fixed or variable speed? Is the coolant actually over heated? Just running with the radiator cap off doesn't prove much, and the system doesn't work properly when not under pressure anyway.


Please include the year/make/model info, at least for the chassis. Cooling systems vary by both chassis manufacturer and sometimes the even chassis model/configuration.

2005 HR Endeavor 40PDQ, Cummins ISL 400.
I replaced the thermostat twice the last from Cummins (185F).
Pressure cleaned the rad. replaced the coolant with 55/55 and 3 bottles of water wetter. No help.
Replaced the temp. sensor with one from Cummins and it does not work at all.UGH!
Going to try Scan Gauge D to make sure that it really is overheating.

[rgl]

Is the fan operating ok? Are they a clutch fan on a rear rad? If so, maybe the clutch is failing?Is it possible that the shroud around the fan is missing, leaking ? Was the fan replaced, maybe with a too small unit?

[RonLC]

Those engines are bad about blowing head gaskets close to #6 and then catastrophically failing when other parts start flying around. Overheating is a symptom.

Go here...https://www.wanderlodgeownersgroup.com/forums/index.php... and do a search on head gaskets

[TR4]

Originally Posted by rgl

Is the fan operating ok? Are they a clutch fan on a rear rad? If so, maybe the clutch is failing?Is it possible that the shroud around the fan is missing, leaking ? Was the fan replaced, maybe with a too small unit?

I agree, this might be something to look at.

Bill

[A Traveler]

What kind of fan control do you have? If you have the side radiator, a hydraulic fan and the Sauer-Danfoss fan controller I can almost guarantee that is where the problem lies.

For years we have been told that if this system fails, the “fail safe” mode will run the fan on high. WRONG. My Sauer-Danfoss control system has failed and the fan is stuck on LOW SPEED. The result of this is that on level ground the engine temp will be OK at 190-205. However, even a slight grade will send the temperature climbing to 220+ in less than a minute, with no hope of recovery.

I’ve had more problems with this system than everything else on the coach combined.

I am about to install the Source Engineering Thermal Valve Conversion Kit (the wax valve) and be done with the trouble-prone Sauer-Danfoss system.

[turbogrampa]

Direct drive serpentine belt drive, no clutch, new tensioner. rear rad.