Is there an easy way to improve rear heater performance in extreme cold? It is -7 degrees right now and my rear heater output is barely warm unless at highway speeds. It makes sense considering the hoses are so long. Is there a good way to insulate the lines or possibly routing them inside the van? When I'm out of town I use my van like a mobile office and it would be nice to be warm and toasty.

 

Have you try a new t-stat ? And maybe don't use the rear heat.

 

The t-stat is good and there is no air anywhere in the system. The front output is great all the time but the rear is only hot when driving. I like to sit in the back with my laptop and fold the middle row seat down as a desk. In really cold weather the windows just bleed to much heat to keep the rear as warm as I would like with the front heater. It makes sense considering the slow moving idle coolant has a long cold trip under the van before it hits the heater core. I'd like to think summer is on it's way but it was -5 here yesterday.