Run the truck all night in negative temps or plug it in?

If you keep the engine on, make sure you kick up the idle.

 

Plug it in if you can. Not sure what you mean by the cold leaks?

 

Not a whole lot of benefit unless you haven't treated your fuel. You'll get extra wear from cold starting but not as much as running it for 10 hours at idle. Really depends on how cold you're expecting.

 

I'd let it run. Kick the idle up.

 

What equipment are you on?

 

And how long

 

Depends on how confident you are in your fuel. Plugging the block heater in won’t do much to help if your fuel is bad and your filters plug up.

 

I’d shut it off, plug it in. Any cold leaks, lets you know if a clamps loose. Shouldn’t get any if you have constant tension type clamps. Unless it’s a brand new Truck. Silicone hoses only. Any other cold leaks are a problem.

 

Treat the fuel. Run for a bit and plug it in. .????