At what temperature do you idle no matter what, even if you have an apu

The Series 60 Detroit engine we could just set the idle at 1200 rpms and be warm all night.

Relying on the truck stop to blend the diesel for the local temperature can be bad idea. Because they might not blend it at all or correctly. I remember long time ago in Iowa at a Pilot truck stop. Truck were pumping fuel and gelling up at the fuel pumps because they did not blend the diesel at all and it was super cold like -5 or something.

 

I would previously go to -5 before idling overnight (with a bunk heater, of course)

I've since added a diesel fired coolant heater that heats things up to idle temps within a couple of hours. I am looking forward to shutting the truck off down to -20 or so now that I can run that and the bunk heater all night. I won't chance colder though without block heater, anti gel, and battery charger because I don't trust our winter fuel (or my batteries) beyond that.

 

I would idle, not use the APU, when temps got above 95-100 F or below 10 F. My diesel heater Webasto or Espar would easily keep the cab warm enough for me but I wanted to be sure the truck engine would stay warm & I have no faith the APU or bunk heater could guarantee that.

 

The secret is not to work for a company that doesn't micro-manage driver decisions in extreme temps.

 

2 nights ago. I went to sleep, using the APU, the temperature was 15°.
I woke at sunrise, temperature was -3°. I had blended fuel.

I probably won't idle until -10 going to sleep.
Apu had coolant temp at 39°.

This is 2nd winter with this truck. Last winter, I was either parked at home or south when the subzero cold passed thru.

 

10 degrees is my limit

 

I’ll run my bunk heater down into the low single digits, close to zero and below and the truck runs. I don’t run diesel additives. If it’s supposed to get cold I’ll blend in #1 or stop at Kwik Trip for some of their TundraMaxx.

 

My boss and I have an agreement, if I'm cold the truck is idling, if not I'm getting a hotel and he's guaranteeing the truck will start in the morning.

 

It's not usually the truck stop but the distributor or the trucker supplying it, we buy fuel in bulk, used to get it from Sapp Bros., few years back when we had that massive cold snap around Christmas, coworker gelled up bad in Northern Montana, was able to limp to a shop that got him inside and thawed out, they dumped a bunch of additives to his fuel to help him get back. Meanwhile, all of us were having gelling problems, big time. We found out that Sapps was getting their fuel from the cheapest source locally, Marathon, they were putting very little anti-gel in the mix, we weren't the only ones with the problem. Few months later we switched providers, they get fuel from a different source with a better mix, no problems.