Limping up the mountains

[hockeybuff]

On our recent trip from North Carolina north thru the Blue Ridge Mountains we experienced a few tense moments when the thermostat in our 29 ft. class C motorhome suddenly rose to the most extreme position and refused to drop until I found a safe pullout and waited 10 minutes, then turned back on the engine and waited another 5 minutes until the temperature gauge returned to normal.  Then we resumed our trip at a slightly slower pace -- 55 mph rather than 65.  When we arrived home, I immediately went to the Ford dealer and asked for a thorough checkup.  Everything checked normal with no loss of coolant.  Bearing in mind that a new radiator and thermost has just been install a year earlier, we still feel like we're playing Russian roulette whenever he head south thru the mountains.  Any comforting thoughts on what might have caused this to happen would be gratefully appreciated.

2008 29' Class C Winnebago Outlook w/ Ford Fiesta in tow.

 

[Scott 3]

What was your tachometer saying?  You were probably pushing too hard.  I have lead foot with a pension for the left lane but I slow down when towing.  I believe I've read where people drop into the low 50s regularly

 

[driftless shifter]

Was the radiator replaced with the proper core count? Adding an addition transmission cooler may help.

Bill

 

[Lou Schneider]

I found a safe pullout and waited 10 minutes, then turned back on the engine and waited another 5 minutes until the temperature gauge returned to normal.

If this ever happens again, leave the engine running in neutral after you pull over.  The cooling system shuts down when you turn off the engine and there's nothing to carry the heat away from the internal parts.  The engine bakes in it's own heat and raises the coolant temperature even further.

When you drive in hilly terrain, staying in top gear and maintaining road speed via a heavy throttle creates lots of heat in the transmission's torque converter that is then dumped into the engine's radiator.

Manually downshifting into a lower gear to let the engine run a bit faster will do a lot to keep the temperatures cooler.

 

[BigLarry]

Back in the 1960's I had a truck that tended to overheat when pulling a trailer on steep grades.  Eventually I replaced the radiator with one that was larger and solved the problem.  Until I fixed the radiator, I found out I could turn the heater on full hot and the fan on high and it cooled down the engine quite a bit and eliminated stopping to let it cool off.  I was amazed at how much the heater could cool the engine.  Of course, it wasn't very comfortable in the cab, but it did mitigate the problem temporarily.

In later years I did the same thing when we were pulling a popup tent trailer with our station wagon.  I rarely needed the extra cooling, but it helped when I did.   

 

[RVRAC]

Three things I suggest, 1) try 55 next time and see what results you get, 2) as mentioned above when you stop do not turn the engine off but let it run idle for some minutes, 3) if the problem continues consider adding an electrical fan to the radiator.

 

[Arch Hoagland]

If you have a tailwind you can overheat too as the forced air ram through the radiator is not as strong.

 

[Gary RV_Wizard]

Interesting that you've already had the radiator replaced once in a 2008. Sounds as though the cooling system may be marginal to begin with. What was the previous problem that led to replacement?

An auxiliary transmission cooler or an extra, electric driven fan are worthy of consideration. Either (or both) would likely give you some extra margin of cooling when needed. Not always easy to fit in a Class C engine compartment, though.

 

[hockeybuff]

After 7 years of traveling thru the mountains I had to replace the original radiator because it developed a leak and also replaced the thermostat because it was failing to open properly.  Will definitely heed recommended lower speeds (low 50's) while in the mountains and probably install an oil cooler, as a margin of safety.  Great ideas, all.
Howard (the snowbird)

08 Winnebago Class C w/ Ford Fiesta in tow. 

 

[TonyDtorch]

  no motorhome towing a car or trailer should ever be going up any incline at 65 mph...( legally the towing speed limit is 55mph in N/C )

it's very likely there is nothing wrong with the cooling system, you just overworked/overheated the engine and trans. that motorhome is probably operating at 100% load capacity and you were pushing it 65 up a mountain !


if it ever starts to get hot again , turn the heater on full blast and slow down, if you must pull over and stop... let it idle and DO NOT TURN THE ENGINE OFF !

http://towingworld.com/towinglawsbystate.cfm?state2=NC

slow down and stay cool...

 

[robertusa123]

I recommend  adding a engine oil cooler.  They do wanders when the radiator is not up to the Task.  I have one on my tow van. A Chevy with the 350.  I can tow up a grade with it floored all the way Ac on in the summer and not over heat

 

[pchicken]

Did the Blue Ridge X-Mas 2104 in a 911. Snow blocked the Asheville exit and had to take a hairy little road down. It was fun but wouldn't wanna to it in any RV.  :-[

 

[odwil]

if it starts to overheat on a grade try taking it out of overdrive and slow down if to temp still gets to high pull of as soon a you safely can put in park and rev the engine just over an idle that way you move more air thru the radiator and more coolant thru the engine never stop a hot motor if at all possible thing tend to cook like oil and hoses 

 

[Gary RV_Wizard]

No modern transmission is going to stay in overdrive climbing a hill. The OD activation switch (if any) may be on, but the tranny will have downshifted on its own.

 

[hockeybuff]

Three mitigating factors -- some mountains (i.e. Blue Ridge and Appalachian chains in particular) seem endless and one can easily find himself struggling to find a save pull-out plus the additional obstacle of being hot weather (mid-May).  Luckily it all turned out for the best.
Howard
08 Winnebago Class C w/ Ford Fiesta in tow.

 

[Nomadb1]

I once had a truck that refused to stop overheating. Finally put in a Howe aluminum racing radiator. Fixed it. Even after I lost my fan belt and about cooked it it cooled the engine in about 5 min on the side of the road. NOT smog legal though for those constrained by that stuff.

 

[grashley]

Sorry, but how does an aluminum radiator make a car not smog legal???  There should be no emissions of any type other than heat from a radiator.

 

[TonyDtorch]

Sorry, but how does an aluminum radiator make a car not smog legal???  There should be no emissions of any type other than heat from a radiator.

That would not surprise me...I know out here on the Left coast they can fail you on the visual inspection if they "see" any modifications to almost anything under the hood, even if it's an improvement on emissions levels.

( Sacramento secretly wants everyone to either drive a Prius or ride a bullet train )

 

[Nomadb1]

They feel they can mandate low e window treatments on cars because it would lower need for ac thereby lower amount of gas you need to burn. If I make my car run cooler then originally designed it will not burn as efficiently or completely. I disagree but I don't write laws.

 

[Gary RV_Wizard]

Changing the radiator doesn't make the engine run cooler - it is still supposed to operate at the same minimum temperature (established by the thermostat). But if you remove or change the thermostat temperature range, you can affect engine operating temperature, which will indeed alter the burn efficiency and create more pollutants.