400 Cummins overheating

[KentandJoyce]

Hi Folks, I have a '06 Windsor with a 400 Cummins, 41,000 miles, very well maintained. Just got back from the Nevada desert. In climbing the passes (approx. 7,700 ft. elevation, high 80's ambient temp) the motor temp. got to 214 degrees on several different pulls. I was towing our Jeep Wrangler, no water, empty black/grey tanks, manually downshifting as necessary to keep RPM's up. As soon as I quit climbing and level out or start heading downhill, she cools down immediately to the mid 190's. I'd like to state that I recently changed all fluids including anti-freeze and the radiator stack is very clean with no obstructions. This isn't the first time that it has over heated while pulling hills, one time the temp warning sensor came on, I pulled over and again she cooled off in short order.Is this normal? Should I consider adjusting the hydraulic cooling fan motor to come on sooner, is that even possible? Thanks for any advice.
Kent

[DriVer]

Quote:

Originally Posted by KentandJoyce Hi Folks, I have a '06 Windsor with a 400 Cummins, 41,000 miles, very well maintained. Just got back from the Nevada desert. In climbing the passes (approx. 7,700 ft. elevation, high 80's ambient temp) the motor temp. got to 214 degrees on several different pulls.

Kent, 214° in my opinion this is anything that you should be worried about given the described task that you wrote in your post. The point at which water boils does not matter since your cooling system's coolant and radiator cap operate under pressure and the boiling point of the coolant is raised considerably over the 212° point.

Keep on truckin' !

[hardy1000]

My 07 40 PDQ Dip ISL400 runs 177 - 187 towing my Wrangler in 100 degree weather. I had the gages checked at Cummins because I could not believe it to be that low.

[Norm4015]

214 degrees is not overheating for your 400 hp Cummins ISL. That is a normal temperature for climbing mountains in the summer. I talked to Cummins about my ISL engine and they told me any temperature below 220 is normal and if my temperaature went over 220 degrees I should down shift to increase the rpm to help cooling. But they said below 220 degrees, just enjoy the ride. By the way, I use a VMSpc to get the actual temperature because my dash gauge is hard to read.

[squeak]

I just power washed my radator lots of dirt came out I always downshift to get the rpm up

[Diplomat Don]

Kent.....I don't think you have an issue at 214 degrees. A couple of questions though....are you getting that number from the stock Monaco gauges, Alladin system or something else? When you changed fluids did you go with the OAT coolant?

[KentandJoyce]

DD, I'm getting the reading from my Alladin Jr. system, my dash gauges are analog with no numeric values. I used Peak 50/50 antifreeze. I'm not sure what OAT antifreeze is? If 220 is the high end for temp as Norm states, then I'm in good shape. I'm pretty good at monitoring my gauges, so I'll keep an eye on them. Thanks for all the help.
Kent

[Diplomat Don]

Kent......OAT = Organic Acid Technology. Most motor homes now come with this type of coolant. It doesn't require SCA's or DCA's or checking of them routinely. I flushed my coach about a year and a half ago and replaced with the OAT coolant. My coach runs cooler with the new coolant by a few degrees.

[EngineerMike]

Ditto on the 214 not being overly hot. If you have never seen this temp before, probably good PM to wash (gently) the radiator sandwich elements to get oil & road dirt out for better heat exchange. Otherwise, sounds A-OK.

[Norm4015]

Just some information from Cummins... My first motorhome had a 1999 Cummins ISC engine and it ran 180 degrees on level ground and 190 pulling mountains in the summer. The transmission stayed about that same temperature.

I traded for a 2005 motorhome with a 2005 Cummins ISL and it ran 200 degrees on the flat and up to 212 degrees in the mountains. The transmission stayed about those temperatures too. I thought it was over heating and called Cummins. They said my 99 ISC had a 180 degree thermostat and my 05 ISL had a 195 degree thermostat so running 200 degrees on the flat was normal. I asked about mountain driving and they said up to 220 degrees is normal and if it goes over 220 to down shift to increase the rpm for cooling.

I have a Spartan chassis and I asked them about switching to OAT. They said it would be very expensive and the coolant that came in it (standard old green stuff) is good for 3-4 years and they recommended I stick with it. The coolant level sensors in my engine will not work with OAT and they would need to change out two sensors and reprogram the ECM. With that work and a complete flush and refill with OAT would cost $700. So I decided to stick with the cheap green coolant.

[walt2137]

Ber careful changing to OAT antifreeze, see past below. I bought a used chevy truck that had the antifreeze mixed and had the gasket failure.
I also think you need to clean your radiator and CAC.

Organic acid technology

Certain cars are built with Organic Acid Technology (OAT) antifreeze (e.g., DEX-COOL[11]), or with a Hybrid Organic Acid Technology (HOAT) formulation (e.g., Zerex G-05[12]), both of which are claimed to have an extended service life of five years or 240,000 km (150,000 miles).
DEX-COOL specifically has caused controversy. Litigation has linked it with intake manifold gasket failures in GM's 3.1L and 3.4L engines, and with other failures in 3.8L & 4.3L engines. Class action lawsuits were registered in several states, and in Canada,[13] to address some of these claims. The first of these to reach a decision was in Missouri where a settlement was announced early in December, 2007.[14] Late in March 2008, GM agreed to compensate complainants in the remaining 49 states.[15]
There are rumors that mixing DEX-COOL with standard green (non-OAT) coolant causes a chemical reaction that produces sludge in the cooling system. According to the DEX-COOL manufacturer, however, "mixing a 'green' [non-OAT] coolant with DEX-COOL reduces the batch’s change interval to 2 years or 30,000 miles, but will otherwise cause no damage to the engine."[16]
According to internal GM documents, the ultimate culprit appears to be operating vehicles for long periods of time with low coolant levels. The low coolant is caused by pressure caps that fail in the open position. (The new caps and recovery bottles were introduced at the same time as DEX-COOL). This exposes hot engine components to air and vapors, causing corrosion and contamination of the coolant with iron oxide particles, which in turn can aggravate the pressure cap problem as contamination holds the caps open permanently.[17]
Typically OAT antifreeze contains an orange dye to differentiate it from the conventional glycol-based coolants (green or yellow). Some of the newer OAT coolants claim to be compatible with all types of OAT and glycol-based coolants; these are typically green or yellow in color (for a table of colors, see [4])

[Diplomat Don]

Guys.....Most companies, including Monaco changed over to OAT coolant several years ago.

[walt2137]

Don I think what caused the problem was folks mixing the green with the orange without flushing, If I was going to change to the OAT I would flush a couple times with the heater in the on position.

[Diplomat Don]

walt2137....You're right about mixing them.....not a good idea. I used Final Charge and they actually make a product that converts the standard coolant into the OAT coolant. It's sold primarily to large trucking companies that don't want the down time. It was very pricey.

You'll never clear an entire cooling system of old product without an engine rebuild and hose replacement. I think a small amount after flushing is not going to hurt anything.