Added Auxiliary Heater - now there's no heat!?

[roadtripcrazed]

This is a re-post from the GENERAL VEHICLE MODIFICATION forum, but as it may pertain specifically to a Nissan vehicle I chose to place it here as well.

I recently installed an auxiliary heater in the canopy of my 2010 Nissan Frontier. This is a simple coolant-type heater which is tied into the heater hose in the engine bay. As long as the engine is running at ~1800rpm or higher, there is excellent heat produced in both the cab and canopy. Unfortunately, when the engine idles there is not sufficient coolant flow to produce heat at either locations.

When installing the auxiliary unit, I was sure to include a bypass so I can isolate the original system from the additions. By using the bypass I get solid heat to the cab at all times - idle or high rpm. It is only when I add in the new system that I get a decrease in performance.

I assume this is due to the volume of coolant that the engine needs to circulate. Or is this caused by something else? Air lock? Restriction?

Any thoughts are appreciated. I have attached a diagram of the coolant system to assist those with questions.

Thank you!

 

[gwhipp]

I just read about something similar on another forum. Here is the link to it:

http://www.clubfrontier.org/forums/f23/heater-doesnt-work-when-its-idling-why-54007/

I would take a guess that there is an air bubble in the aux heater.

 

[roadtripcrazed]

I just read about something similar on another forum. Here is the link to it:

http://www.clubfrontier.org/forums/f23/heater-doesnt-work-when-its-idling-why-54007/

I would take a guess that there is an air bubble in the aux heater.

I've read into that as well - on the same forum. However, I can't figure out how to work an air-lock out of the new system. There are a lot more bends, etc. to deal with ....

 

[sasfrontier]

I would take it somewhere and have the coolant drained and then filled using a vacuum fill tool. I work for Porsche and because the radiators are up front and the engine is in the rear there are high points in the system that can't be bleed, as in your situation there is a high point in the system where air may not bleed out. With a vacuum fill tool it pulls a vacuum and you shut a valve then open a valve on the tool to allow the vacuum to pull coolant into the system. The other option for you is to add some sort of t valve at your highest point in your new heater system then open it slowly while the vehicle is at temp and see if you get any air out or just coolant (be very careful as you could get burned easily if you open the valve all the way or to fast).

Also are you trying to heat the both spaces at the same time? If so you may be disipating to much heat through the heaters (i.e. "radiators") and may need to have them hooked up in parallel instead of in series for better heating efficiency.