Community Forums

gjos · 10-13-2021, 09:48 AM

I've been is some chilly weather with my coach, but this is the first time for really cold prolonged temperatures. Im in W Yellowstone and for the next week temps are in the teens at night and some days never getting above freezing. If I keep the floors heated and my fireplace going, the Oasis never kicks on when set to 67. I was feeling good about the diesel savings until I started thinking that the furnace keeps the basement from freezing. I've noticed before that my floor heat keeps the basement warmer than ambient, but I don't think that I should rely on this. Is there a thermostat in the basement that will trigger the furnace independent of the coach temperature? If not, then I guess I need to turn the fireplace heater off to cycle the furnace in order to protect the basement.

R.Wold · 10-13-2021, 10:02 AM

Something to think about driving in temps in the teens. They say DEF freezes at 12* but twice Ive had errant low def warnings driving in these temps and my “belief” is that while this may be true in a tank or jug, it might start to slush at higher temps (teens to 20’s) in the lines, reducing flow to the doser and causing the low def response. So if this happens to you, it may not be the dreaded DEF head failure but a temporary condition.

ThunderRidge · 10-13-2021, 10:14 AM

The furnace will come on when it needs to. There’s a sensor for the basement heat. I believe it’s 45 degrees, maybe 40.
I’ve camped in below zero temperatures and the DEF has not been a problem.

Dutch Star Don · 10-13-2021, 10:58 AM

Keep in mind, if the floor hear is left on, it not only radiates up into the coach, but it also radiates down into the bays. I've always kept an indoor/outdoor thermometer in the basement to keep track of the temps....mainly high temps in the summer.

I think if you were to check the temps in the bays, you'll find them in the 40's. If your concerned about the DEF, throw a 100 watt trouble light in there. The bay heater won't reach the DEF tank because it's in the water bay, but the floor heat may be over the DEF tank and providing some heat.

R.Wold · 10-13-2021, 11:48 AM

DEF in the tank should be fine even if it starts to freeze while parked because the in-tank heater will warm it up when the engine is running. My issue, if it was the cold, occurred twice while driving in mid-teen temps, and Im theorizing the stuff was turning to slush in the line between the pump and doser, because it self-resolved later in the day. But Im not certain, and only mention it because if you do experience erroneous low def warnings under these conditions this may be the cause and not a bad DEF head.

And yes, I do have floor heat envy...

Dutch Star Don · 10-13-2021, 02:24 PM

R.Wold made me think of something else, but don't know how effective it would be or if it would even work. The DEF tank has coolant lines running to it. If the block heater was left on, which heats the coolant, it MIGHT migrate to the DEF tank lines.

Either way, in those temps, you should be running the block heater the night before your planned departure day.

Rev. Roy · 10-14-2021, 12:04 PM

My wife and I are avid cold weather campers, many night below 0, so I can share what we do. First, the basement has a sensor and the heat will come on. We've never had any issue with DEF in cold weather. I always add after market anti gelling additive to the diesel tank. I know we have a block heater but I do that so it won't gell and clog the filters on the Oasis furnace or the generator. Is that necessary? I don't know but I'd rather error on the side of caution.