Community Forums

Cfyanes1 · 06-22-2016, 12:06 PM

Getting ready to find cooler weather in Colorado. We will be climbing a couple mountain passes. Do you turn off your dash AC when climbing. Any other considerations & thoughts would be appreciated

gemert · 06-22-2016, 12:10 PM

Quote:

Originally Posted by cfyanes

Getting ready to find cooler weather in Colorado. We will be climbing a couple mountain passes. Do you turn off your dash AC when climbing. Any other considerations & thoughts would be appreciated

I never use my dash air. I've been told and I believe that running the generator and house AC uses less diesel, is more efficient and does not sap horsepower.

kenandterry · 06-22-2016, 12:11 PM

Only if the engine temp gauge really starts to climb do I shut down the A/C. Just back off a bit....don't need to be the first guy up the mountain....and enjoy the scenery.

Waiter21 · 06-22-2016, 12:32 PM

I run the dash AC, and keep an eye on the temperatures. If engine starts getting hot, its time tio shut the dash AC off.

NOTE - When I climb, I force the transmission into lower gear and climb at a slower speed. I've never had any problems with temperature as long as I keep the RPMs up and select my gear so the throttle is never on the floor.

Sweetbriar · 06-22-2016, 12:32 PM

I do the same as kenandterry. Watch the engine temp and don't rush. I have run the generator and roof A/C when the heat is too much for the dash A/C but have yet to have down for engine loading and cooling purposes.

Take your time and pull over to allow those going faster to get by. Down shift and keep the RPM high which will spin the water pump faster to get a higher coolant flow rate to pull more heat from the engine.

ernest917 · 06-22-2016, 04:47 PM

Are you driving a gasser or a diesel???? Can't see that it makes much difference with my diesel... Keep in mind that you will be at elevation and most likely you won't even need your AC....

MSHappyCampers · 06-23-2016, 09:32 AM

Quote:

Originally Posted by ernest917

Are you driving a gasser or a diesel???? Can't see that it makes much difference with my diesel... Keep in mind that you will be at elevation and most likely you won't even need your AC....

X2 !

DeWat · 06-23-2016, 10:58 AM

I wouldn't be able to tell you if the dash AC in any of my motorhomes even worked (and that included 2 gassers, a '12 Thor Hurricane 32A and a '13 Winnebago Vista 35B). At 1 gallon or less per hour, it's always been the generator and all roof ACs for us. Keeps the entire inside of the coach nice and comfortable while giving the generator the needed exercise at the same time.

EDIT: and of course running the generator and roof AC has absolutely no impact on the engine or performance.

Atom Ant · 06-23-2016, 11:02 AM

I run mine, the few times I've got to use it so far. Mine runs super cool anyway (not sure that is a good thing).

My Ford pickup used to kill the AC somehow when really pulling. It would blow air, but it would get hot after a while. Once you started decending, it would cool right back down. I don't know if the gas motorhomes do that or not.

tderonne · 06-23-2016, 01:43 PM

Quote:

Originally Posted by Atom Ant

My Ford pickup used to kill the AC somehow when really pulling. It would blow air, but it would get hot after a while. Once you started descending, it would cool right back down. I don't know if the gas motorhomes do that or not.

This.

Any modern vehicle will kill the AC at some combination of pedal position, engine load, air temperature, water temperature, time, and other parameters.

Leave it on.

1ciderdog · 06-24-2016, 02:02 PM

I use dash AC and don't turn it off on grades or in the mountains unless it is 90 degrees or above outside, then I turn off the dash and run generator and house AC. This works for me.

Sky_Boss · 06-24-2016, 02:27 PM

Your brand might be the same, might not but...

On our side radiator, Newmar running the dash AC will lower water temps nearly all the time. My water temp drops from 200* down to 180* on the flats. OK...I know you are talking about mountains but bear with me.

I have found that my fuel mileage (combined driving and generator use) is as good or to a minuscule extent slightly better running the generator for AC instead of the dash and in most cases I feel more comfortable. The main exception to the comfort factor is driving in hot weather into the sunset and then the dash air is needed for direct airflow.

Why am I seeing this?

Newmar specs out that the radiator, CAC, transmission cooler and AC condenser are all sandwiched together. When the AC calls for cold air it locks the radiator fan into high. That forces unneeded cooling of the engine coolant with some reduction in engine efficiency. This is then coupled with the relatively small horse power drain for the hydraulic fan. But it all adds up.

I'm not saying it is a total wash because, of course, more hours on the generator means more frequent oil and filter changes so that has to factored into the equation. Still, by running our generator while traveling eliminates the need to exercise the generator simply for the lack of use. It might be a wash under some conditions.

So, if you find your coach has a similar set up then maybe running the whole debate about AC on or off under stressed conditions is moot?

You can verify if your system works like mine if you have a digital water and tranny fluid temp readout. Simply get things up to temp without the dash AC and then turn the AC on to MAX and see if you get the same results. If not...none of what I have and will say (except using high RPMs during climbed) applies to you. Pretty simple.

BTW...as has been said, keep that RPMs up during long climbs. That circulates coolant faster along with keeping the radiator fan speed up for the task.

BTW#2...If you understand this and it applies to your coach then you can use that to your advantage. During stop & go traffic on hot days when you start seeing water and/or tranny fluid temps rise, turn on the dash air to MAX and watch those temps drop.

BillJinOR · 06-24-2016, 02:42 PM

I have a c12 ( the precursor to your c13) its a very large engine with major torque .. I climb the passes with out even thinking about it if your cooling system is working properly you won't have any problems. Perhaps figuring how to pass everyone else. �� If it's hot out we run the gen and all a/c's !!!when I arrive I want the entire coach to be comfortable. Does it cost more in fuel ? Don't know and don't care, with the money I spent on this rig a mpg one way or the other is a drop in the bucket.

JgatorAZ · 06-24-2016, 04:50 PM

Just this weekend running in the 100's from Payson down to Phoenix through multiple 1000 to 2000 foot 6 plus percent climbs and had the AC on max with the pedal to the floor to keep the coach above 50 mph. No issues at all.