[jdkskyking]

UPDATE (10/4/2025) CUT TO THE CHA$E!

We completed a trip to Breckenridge Colorado from Bentonville Arkansas and back. First big trip in two years.

The Newell climbed the Rockies without any trouble or overheating while towing a Jeep Gladiator.

What was different on this trip?

1) I modified the coolant system by adding a temperature sensor that controls the hydraulic manifold solenoid controlling the fan speed. At 212° the fan goes to high until the coolant temperature reaches approximately 204° and the system resets to fan low speed (normal ops).

2) I re-pitched the cooling fan to 25° for more airflow. This pitch is an intermediate pitch that improves airflow but is not enough for optimal performance. When I complete the hydraulic system modification with a dedicated hydraulic pump for the cooling circuit, I’ll re-pitch the fan to 30-35°. I need to move more air through the radiator and engine compartment.

3) New Radiator - Newell installed a new radiator last year. This made a significant improvement despite all of the work I did trying to clean the original unit.

4) New CAC - Newell installed a new Charge Air Cooler which was a game changer for the Caterpillar C-13 Compound Turbocharger system. I’m now seeing as high as 50 psi boost in some conditions.

5) Divorcing the transmission from the radiator - installing the stand alone transmission cooler was a game changer for my transmission. Fluid temperature is now rock steady at 194° F not being influenced by constantly changing coolant temperatures.

Bottom line… new components and adjustments/modifications were necessary to getting closer to having a fully functioning and normal performing coach.

$$$$$$money$$$$$money$$$$$money$$$$$

Back to the original post….?

Good afternoon Newell owners,

We’ve got the Cat-13 ACERT in our rig. On our last trip we experienced fluctuations in our cooling temps. The cooling temp increased when we were pulling Colorado mountains more than I liked. Thanks to Newell’ Mike E, Richard, and their expertise we were able to manage our situation. 

Now I’m entering the question and answer game with our 15 year old cooling system. So many variables to look at in this scenario. 

I have no idea how many rigs have the C13 engines, my guess is not many. If you have one or had one I’d be interested in hearing how yours behaves. Before we left on our trip I added a PDI Big Boss Tune. I have no idea if it’s a contributing factor good or bad. I’ve been told by a C-15 owner with the tune he notices no difference. IDK...

My immediate questions:

After warm up, in normal operating conditions, what’s your coolant temp run? Does it fluctuate +-20*?

How does your hydraulic cooling fan behave? Slow, med, high speeds? Is it idle at times? If you unplug the fan solenoid does your fan blow your hat off?

How often have you had to change the engine thermostat? Sensors? Modifications in general?

How does the coach climb a grade in high altitudes? Hot temperatures? Heavy? What speed to you climb a grade at... usually? Any special techniques used? Manual shifting? Maintaining a specific RPM band? 80% throttle?

Have you ever had scale buildup in your radiator reservoir, radiator, plumbing, engine? (Loaded question because you have to take stuff apart to find out and that’s not fun. I have some scale buildup in the throat of the reservoir. Soon I’ll drain it and borescope it to investigate more but possibly someone has had work done that could help me understand what could happen to the inside of a radiator). 

I know Caterpillar makes a great engine.  They’ve been around for a long time and moved dirt around the world. I’m still learning all I can about these big Diesel engines and in some cases more than I wanted but that’s part of playing with the big boys... 

I’ll appreciate any info anyone has about how’s these machines behave when traveling around this great country. This topic is cooling...  When I’m done solving this issue I certainly hope it helps others understand a little more about the machine that follows us around all of the time... 

In normal operating conditions I’m seeing the coolant temp fluctuations anywhere from 165* to 185*. Pulling a grade, high, hot and heavy, we’re seeing above 215* at the toughest times. When we pulled over the temps decreased to normal range in less than two minutes. 
JK

[Fulltiming]

You are correct, Newell did not use many C-13's. Although I am certain there were a few more, I am only aware of 8, 6 in model year 2005 and 2 in model year 2006. There were a few C-12's back in the 2003 model year. Most of the hydraulic cooling fans I am familiar with have a high speed and a low speed. When the solenoid is unplugged, they will all default to high speed so that is normal. Since I don't have a C-13 I will leave the driving and maintenance details to someone that does.

[jdkskyking]

Thanks for the information. 

When I’m checking the hydraulic fan system, do you recommend a engine RPM setting that will provide sufficient hydraulic pressure to ensure the fan is operating at a speed that will yield the two settings? 

JK

[encantotom]

on the series 60, at high idol, when unplugging the solenoid at the hydraulic block in the back near the radiator the fan will roar.

when it is plugged in the fan may or may not run depending on the temperature of the engine. sometimes the fan will not be running, sometimes very slowly and if really warm (below 204 on the series 60) if will run but not roaring.

on my series 60 when the engine temp hits 204, the high speed fan mode kicks in and it will cool the engine down very quickly.

tom

[bikestuff]

Jeff,

On my C12 the temperature stays at 186 for most of my driving. However, if I get stuck in traffic on a hot day, the temps will rise up to about 205 but then start dropping once the fan cuts on. In other words the 20 degree range of coolant temps are perfectly normal.

So....do you see the 20 degree swing when the engine is not under load?

Have you verified that you have enough water/coolant in the radiator (from the filler cap not the overflow tank)?
Have you dipped out some of the coolant and looked at it? I have heard that if you mix different incompatible kinds of coolant, you can cause a sediment to form that can be suspended in the liquid. I believe it would show up as a cloudy sludge in the coolant.
How clean is your radiator / CAC? If you open both side bays of the engine you should see light through the rad. If not, there are a couple of threads on here about cleaning your radiator....but be careful of Simple Green. It reacts with aluminum. They say the Simple Green Extreme is safe for radiators.

From what you wrote...the 165 on the low end sounds strange....too low. That would point to a thermostat that is stuck open. If the temp is moving around a lot when engine is not under load, I would suspect a temperature sensor...but to be honest I have no idea where mine is. (You might want to drop into a cat dealer and get them to look at thermostat(s) and do a fluid analysis. (They can do coolant AND oil)...that might tell you something.

bill

[jdkskyking]

My current game plan is:


-Verify coolant temps with a IR temp gun. 

-Verify coolant level. 

-Inspect coolant reservoir for integrity, inspect caps (two), drain and clean, consider a SS replacement. 

-Pressurize coolant system and leak down check. 

-Isolate cockpit heating lines to eliminate possibility of leaking heater core.  

-Identify engine coolant temperature sensors and test 

-Replace engine thermostat. Opening that housing may give an idea if there is buildup in the coolant system. 


That’s where I’m going to start.

Thank you for the tip on Simple Green, I was going to buy some this morning. I had no idea regular SG was harmful. 

Thank you!
JK

[encantotom]

at least on the series 60 coaches, newell put 4 old fashioned valves in a manifold to isolate the coolant lines going to the dash and the aquahot. they are on the framerail on the drivers side just inside the back of the coach. on mine there is a plastic plaqueard that labels which is which. one valve is going and one is coming back.

a word of caution is that they are not ball valves so exercising them may make them leak. at least it did on mine.

tom

[jdkskyking]

I’m assuming you changed them out?
What did you use?

[encantotom]

actually no. what was my problem was my dash heater core sprung a leak. my aquahot has lines that run to the dash for defrost and there are aquahot heaters at the drivers and passenger seat ankles so i just wanted to turn off the lines that run to the dash. i did so and the valve at the block in the rear i am referring to started leaking. they only leaked when they were turned off. so i took a short piece of heater hose and put it between the in and out valve on the block and turned them both back on.

the valve that was leaking was in the middle of the block so i would have had to replace them all.

so i took the cheap and easy way out

tom

[jdkskyking]

Great idea!!