65-66 owners or ex owners please respond

[sixystyle]

we just bought a 2nd addition for our stable. a 65 with a fresh 289, car runs and drives great! has some rust issues.....no biggie. but the defroster sucks! I looked at it tonight and all the hoses are hooked up, door moves good but when you open the defrot ducts it still leaves the rh floor duct open and about 50% of the air comes out there. I dont see where there is anything missing or broken. It just looks like a piss poor design to me. I have also worked on alot of these cars for other problems and have noted the same thing with them. Are they all like that??

[bmxmon]

I've had problems with mine too, though I'm pretty sure my linkage and whatnot is messed up. The hoses that run from the box to the defrost vents always come off on mine too.

[sixystyle]

Have you looked at how it shuts off the defrost and how it opens etc.? My plenum looks to be untouched but no matter where you set the defrost it leaves a big hole open to the floor on rh side of tunnel. Thanks for you input alex........if these are all that way I am going to do sometin with this sucker! All the humidity in the pacific nw it would have to idle in the drive way for 2 hrs before I could drive it to work! I couldnt imagine what would happen if it frosted.

[rwhite65]

It probably wouldn't hurt to rebuild the whole heater unit and assembly. I took mine out and re-did it, taking my time. But in all honesty, it really isn't that hard or long of a job.

Then you would be able to get in there and see if it is all working correct.

[jwboner]

You are right. The 40 year old design isn't that good compared to today's standards. And just blowing hot air on the windshield doesn't always cut the frost away.
The best advice is to remove it and get a modern a/c unit and defroster in one from Vintage Air or somebody like that.

[dav65mus]

I have owned 6 different 65-66 mustangs over the last 28 years and back in the day when I was in highschool (80-83) I hated the defroster on my 66.

I used to carry a roll of paper towels in the car with me and when it was cold and damp I would wipe the moisture off of the inside of the window

I did not have a leaky heatercore or hoses, it was just humid,cool, Louisiana winters.

The previous poster hit the nail on the head.... new cars have dehumidified defrost air.... old mustangs don't.

I currently own 2 65 stangs a coupe and a fastback, but they are only fun good weather drivers so the defrost does not matter.

You can get a modern air/heater/defrost setup made for classic stangs that will work like a newer car, but they run around $1k for a kit.

Good luck