Technical Hot air through fresh air vents

When driving my 55 Ford with the fresh air ducts open I get very little air movment and extremely hot. Any ideas how to cure this.

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Join the 52-59 Ford social group here on the HAMB. Lots of good info plus how to fix this. I canthelp because I removed mine.

 

Make sure all the outside air ducting is clear.

If the outside air is routed thru the heater case, make sure the coolant shut-off valve to the heater core is closed. Not sure if your car even has one but you can easily add one to the heater inlet hose. In a bind you could even rig up a garden hose shut-off valve.

 

As was mentioned, make sure the wire mesh inside the grille isn't blocked with debris and these cars didn't have the best ventilation system anyway, the hot weather doesn't help ether. HRP

 

The right side air flow CAN go by the heater core but not the left.
Does yours have the Delux heater? The wiper vacuum line tees off and goes into the heater box. When you move the cold/heat slider it actuates the vacuum to the valve on the front of the intake allowing water to circulate thru the heater core.
Some remove the valve and put in an elbow and hot water flows thru the core all the time. A mechanical shut off is available so you can close it in summer and open it in winter.

When my heater is off and the trap door shut the air on the right comes in fairly high under the right corner with the selector on right air. When closed, no air flows.

 

Put in a Vintage Air unit, then it will be cold air. Or just wait until winter for colder outside air.

Vent air will always be hot to a certain extent, more so if the ducting goes by the engine or exhaust. Even windshield cowl vent air is warm unless it's a cool day. Just because it's fresh air coming in doesn't mean it's any cooler, just means you have more air coming in.

 

The drivers side fresh air vent is a straight shot to the front air intake, controlled by a pull knob to the left of the steering column that operates a fresh air flapper valve. If you're not getting air movement when the valve is opened and the screen in front is clear, you probably have a rodent nest in the vent. There's a tin sleeve connecting the inner fender panel duct to the body that's lined with fiberglass; it's a favorite spot for nests. Remove the sleeve and clean. Make sure the tin flapper valve is hooked up and has free movement.

The passenger side vent if the car is equipped with the base heater (single heater control knob on the dash) or no heater will be the same as the drivers side, except the pull knob will be under the dash. Probably the same problem.

If you have the Deluxe heater, it's essentially the same except the sleeve has a 'tee' to the heater fan, and the fresh air flapper valve is operated by the heater controls. Again, check for flapper valve operation and nests.

Heater temperature control is done with the vacuum-operated valve on the intake if you have the Deluxe heater. If that valve is missing (very common as it's expensive to replace), you have no control. The base heater lacks the valve from the factory, the owners manual states that you can 'regulate temperature by rolling down a window'.

 

I’ve had a number of the vacuum operated valves that work at low rpm, but at 3000 rpm or so, you get a sudden flow of heat. Apparently it won’t hold the even minimal pressure from the water pump. Likewise with the “aftermarket” replacement valves sold by the t bird guys.

I’ve taken to hooking them up to the garden hose to check them first.

 

For the vacuum actuated valves you might try finding one of these vacuum check valves to put inline in the vacuum hose. It should help delay the vacuum drop at higher RPMs and during acceleration.

Probably easy to find at the salvage yards or looks to be still available new thru GM or ACDelco jobbers. Just not sure what hose size you're working with.

 

Hi...All of the above posts are correct..... So the idea is to eliminate as much heat as possible...Obviously we can't change the ambient temperature...As per previous posts there are various ways to shut off the hot water...take your pick...if after eliminating hot water and cleaning the ducts we still blow hot air here are some considerations....the metal vents absorb heat from the engine compartment...in a car that has been lowered the under hood temperature increases because there is less space for air to escape...the answer? remove any mud guards from the wheel wells and front of engine...anything you can do to help ventilate the engine compartment...We actually took the ducts apart as far as we could and glued a thin layer of insulation on the insides...lot of work but every little bit helps...

 

My '59 passes a lot of air through the vents. I took the cables apart and made sure they all worked easily, actuated the flappers in the tube under the hood to make sure they were free and open. I had my screens both off, found a heater hose clamp in one side... assembly line humor.

I'm missing the door seal on one side so I get hot air from the engine compartment bleeding into the interior on hot days, one of the little things I have to install before winter.