When to leave Truck Running overnight

Do you have a block heater? If so, plug the block heater into the apu and the truck will start easier. I'd leave the truck running anything below 0, block heater or not.

 

-15 here in Wyoming...the truck hasn't been shut off since yesterday morning.

 

The APU should be hooked into the block keeping it warm without the truck running. Any good APU is anyway. My tripac has a temp sensor so that when it gets so cold out it kicks on wether the batteries need it or not so it keeps the engine coolant warm and flowing through the block also.

 

When you get down to maybe 15 degrees and lower you want to consider idling, -15 definitely. That cold and you usually have wind involved making it that much worse. Richter it varies but many APU's are tied in with the truck's cooling system but it's not powerful enough to keep up in single digits. Also that cold I would consider keeping the brakes off if there is snow/ice around to keep them from freezing shut. Chock the tires. Avoid parking with the truck angled even slightly down hill on ice or snow or you might get stuck. Not just treat your fuel use brake line antifreeze. Disconnect your trailer lines, hold them up in the air and pour some brake line antifreeze in each side, then cycle your buttons a few times. Repeat a couple times.

 

Depends on the apu. Tripacs do have that feature (also keeps the fuel warm,) but it is a customer option like other apu's. I have a pos dynasis apu, and the engine was struggling to start at 15° yesterday morning. At -15°, I don't know if it would start. On top of that, cold batteries have about half the starting power that they normally have.

 

From what i understand, most have their own cooling system these days and relly ont he block heater to keep engine warm. This is so if apu fails you can run the truck still. You can also run both apu and engine at same time without overheat. I know rig masters can be set up either way, but they recommend not connecting to truck coolant. I htought tripack was designed no to use truck cooling these days as well. I think the joint collant is the old school way of doing it based on info from a few manufactures recently. Rigmaster recommends pluggin blockheater into apu.

 

When to leave the truck running...

Whenever you are in an area where if by chance your truck wouldn't start, you would be part of the food chain.

 

Another thing to mention is climate control. At those cold temps, the apu heater (especially if it's electric) just doesn't have the oomph to keep you warm all by itself. I have been running both my engine and apu to keep warm and have shore power. If the company doesn't like it, then they can put me up in a hotel.

 

So what rpm do you guys idle at ? I was always taught close to 1000 so it has enough oil pressure and does not slober oil.