how long for heat

Yep, I'll explain it.
The CAC requires consistent air not only to keep it cool but also to keep it from distorting. When you block air flow it allows part of the CAC to expand a disproportional amount compared to the non blocked section.

If a working truck can't keep a constant temperature then in all likely hood thermostats are required.

 

i don't know about yours but mine will idle at 600 rpm until it heats up a little then it jumps to 700 rpm. it depends on how the ecm is programed.

 

i use a winterfront where im at 15 to 20 deg. it will run at 170deg. with the winterfront it will run around 190 deg. all day. and the fan doesn't kick on once. warmer is better! but not to warm.

 

I have found this is normal amongst Detroit engines.

Every Detroit I had did this. Idling, they wouldn't stay warm to save there lives. Even when everything was running the way it should, water temp would fall to 160, 170 idling. As soon as you get going, your working the engine so it generates the heat needed and gets back into the 200 range. I had to shut the heat off periodically going down the road or I would have roasted my walnuts.

I always guessed the Detroit's had a hard time keeping water temperature at idle because there a small engine. I never had that issue with big 14.8L CAT engines. Technically that shouldn't have anything to do with it, but I can't think of why EVERY Detroit I have been in has acted the same way, maybe it was a fluke and I had a bunch of bad trucks.

 

I have a hard time keeping my ACERT at 180 or better when things get much below freezing. Is there a hotter thermostat we can go to ?

 

And NJ will only let you idle 15 minutes every 3 hours when the temp is below 25 . None of our trucks have APU's . That's why I refuse NJ loads . PA is the same way . I do a drop and hook in McAdoo , PA but stop in VA the night before .