Heater question regarding residual blow through

[cfriedman67]

I have the factory five suppled heater (2016) with a Gen 3 coyote in my roadster. When the engine heats up and the heater swithed off I am getting a small amount of heat coming though the vents. In the hot summer months its enough to be annoying. I have the switch on the dash pushed all the way in and it is not turned on. I found some old posts back from 2013 and is states that the blower is open to the engine bay so that hot air from he engine bay is pushed through the system. Does anyone else have this issue? One suggesion was to cover the blower intake in the summ
e and remove it when it cools down.
Thanks Craig

[Nigel Allen]

I recall someone mentioned using a shower cap to cover the heater assembly. Effective, but not pretty

[ptstew]

Hmm, I have that problem, too. I think maybe I’ll try to find a black shower cap. Thanks.

[boat737]

I made a shroud to cover the blower motor. The intake for the shroud is the PS foot box. Be aware that the blower motor sucks air from both sides of the squirrel cage. Here's an old thread from my heater install that shows the shroud.

https://thefactoryfiveforum.com/showthread.php?20883-Vintage-Air-mounting-modification

[Blitzboy54]

I get the blow through but do not get hot air as I have the heater valve shut. Your still getting hot air with it closed?

[cfriedman67]

Yes I still ge hot air wih the valve closed. I assume i is pulling hot air from the engine bay.

[cfriedman67]

Thanks for the info. I read that some one velcro'd a piece of aluminum on the driver side of the unit. I might give that a try and remove it when it gets cooler out.

[GTBradley]

Boat737 has an excellent mod for this very thing. If that heater box were better designed it would have the ability to take outside air. That way you could use it for cool air too, but it just blows hot in summer months. I plan to mod mine some day, but for now I put a tennis ball can lid over the left side. For the right side I had to cut a strip of thin aluminum sheet and wrap it around the intake. They both remove easily if needed.

[nuhale]

You are not alone in this. The only damper in the whole system is the gimbal vent louvers which does little to stop the airflow. When moving the air pressure build in the engine bay forces the hot air through the blower fan. The hot air is not coming from the heater core with valve off. In hindsight a fabricated box with some sort of damper in the bay would have been ideal. I've used a plumbers plug in the round opening of the blower but there is still flow from the electric motor side. My solve is using a black plastic disposable shower cap over the whole unit which works pretty good. Easy on/off too so little hassle. I keep a couple in my trunk tool bag.

[egchewy79]

I've notice the same. Time to get a shower cap. Of interest, I read Boat737's post on this a couple of years ago during my build and stole the idea of the aluminum strips on the inside of housing to get a more solid attachment of the heater to the firewall. works like a charm.

[cfriedman67]

You are not alone in this. The only damper in the whole system is the gimbal vent louvers which does little to stop the airflow. When moving the air pressure build in the engine bay forces the hot air through the blower fan. The hot air is not coming from the heater core with valve off. In hindsight a fabricated box with some sort of damper in the bay would have been ideal. I've used a plumbers plug in the round opening of the blower but there is still flow from the electric motor side. My solve is using a black plastic disposable shower cap over the whole unit which works pretty good. Easy on/off too so little hassle. I keep a couple in my trunk tool bag.

Thanks for the idea. Going to order some right now. Sounds like a simple fix to get me trough the summer unil I get time to make something more elaborate.

[CP82AERO]

Here's what I'm going with--the dash bulkhead will have thermal/sound mat and so hopefully the air drawn from that space will be pretty close to ambient.
169554

[nuhale]

Here's what I'm going with--the dash bulkhead will have thermal/sound mat and so hopefully the air drawn from that space will be pretty close to ambient.
169554

That should help but you still will get airflow from the fan motor side (unless you covered this somehow).

[J R Jones]

My 2JZ cooling system requires coolant flow through the heater core. I mounted the core in the engine compartment with the Spal drum fan and air intake in the cockpit. The fan blows air from the cockpit through the core and back into the interior. With the fan off there is no air pressure delta to flow and the core radiant heat stays in the engine compartment. All duct housings, no hoses.
jim

[Walt]

I had the ffr heater set up in mine and had the same issue, found out the water valve that came with the kit does not turn all the way off. I replaced it with a Ford unit from O'Reilly and it fixed the problem.