My defrost is worthless!

[Internexus]

I have a 65 stang and the defrost is absolutely worthless, is this common amongst all 65-66 stangs or is something seriously up with mine. I get about a 6" round area cleared out on the drivers side and a 10" long strip by 3" wide on the passenger side after forever of defrost being on full blast.

 

[Nosboss]

My '66 does the same thing. I have only had to use it a couple of times and it truly is worthless. How did they get by in the old days when the car was new???

 

[rbohm]

understand that modern cars use the a/c system to help clear the windshield because it acts as a dehumidifier. older cars used air that was directed through the heater system. take the time to warm the car up a bit more before turning on the defroster, and it does work a bit better.

 

[Internexus]

I don't bother flipping on the defroster until the car is completely warmed up as is.

 

[ForceFed70]

Havn't used it much, but when I did the defrost on my '70 worked pretty good.

Does it have good airflow, nice and hot, etc? Prior to changing the heater core, my heat hardly worked at all. Turns out the heater box and heater core itself were completely plugged up due to mice nesting.

 

[Internexus]

The 67+ model cars had a different defrost vent system that is more efficient by default, you have slats across the window we have 2 round openings pointed at the moon.

 

[Edster]

Are you opening the vent/wing windows any? These only let in a a small amount of air but also suck out air as well. This will help your defroster out. Also check the condition of the defroster duct and its cones at the register. Sometimes these go bad as the register cones are made of paper and rot. Also the heater plenum may be faulty and it was paper too. Lastly check you linkage for the heater system. A long shot but it is a possibility are pin holes in the heater core or a loose or faulty heater hose.
The older systems weren't that bad as long as you used the system in conjunction w/ the vent/wing windows. I believe they were supposed to be used in that manner. Half of the cars I have owned have had vent/wing windows and I always used them in conjunction w/ the defroster and had few issues although it did take a little longer to defrost. I sure wished they still put those things in cars today, sometimes I want just a little fresh air but not all the wind and road noise.

 

[Internexus]

I have never heard of using those in conjunction with defrost, do you just crack them slightly? I will give this a shot on the next chance I get and see what happens with this.

 

[Edster]

Yeah just crack them open about 1/2 to 3/4 inch. Now of course this will only start working when you start moving but once your moving it works better. Also at lower speeds you may need to
crack it open more then at higher speeds. It won't be that much colder in the winter not like riding your bike!

 

[jcp123]

Do what they said above, let the car warm a bit. But also, how about the little hoses that take the air to the vents? In my '68 I used to have, these hoses were shot, hence, no defrost. That was fun when we were on the interstate in a rainstorm in that flat evening light with a frosty windshield, slow wipers, on a bridge over a lake.