Rear defrosters?

[Semjon]

Anybody know the exact story on these rear defrosters? My car didn't come with them and had the holes welded up.
I also see different results in restorations, some cars have them and some don't.
Just curious if there's an idea behind it.

[304065]

Sure, there are small circular holes on the rear corners of the parcel shelf- all the way to the outside, all the way back. These defrosters go in the holes with the tubular part in the engine compartment. Inside the engine compartment, the unobtanium orange foam defroster tubes connect to the circular tubes on the frame rail. Hot air from the heat exchangers blows through the heater box into the frame rail and some of it works its way up and defrosts the rear window. (So effectively that electric defrost was later added )

[docrodg]

I will also add that many people delete them for a few reasons:

1. The smell of an aircooled engine heater.... "I love the smell of 10W40 on my drive to work"
2. Heater delete plates are installed on the engine cover to block off all heat from the fan to improve cooling to the cylinders, thus leaving the system inoperable - the defrosters are stripped to block the air and save weight.
3. SInce the hoses are indeed made of unobtanium foam they get taken off to prevent cold air from getting in when they deteriorate.

[Semjon]

Thanks guys! Already had that idea since mine were blocked off in a not very factory style
But since I'm going for originality I should add them again...

[kentf14]

I had them still in my old '65 build '66 MY also. To avoid the gas and oil fumes I discovered that a strategically placed wine cork on the engine bay side was just the thing to plug them up.

Kent

[Semjon]

Got the Porsche part number for that wine cork ?
Just a question for the purists out here; put them in or leave them out?

[edmayo]

They (the defroster pipes) are in and operational on my 67. Since it is meant to drive, there just too many times when I need a rear window defroster, such as this past weekend. An early 911 event down in the Texas Hill Country, morning dew on the glass, nice to have working defrosters, so you can see the car behind you.

[docrodg]

They (the defroster pipes) are in and operational on my 67. Since it is meant to drive, there just too many times when I need a rear window defroster, such as this past weekend. An early 911 event down in the Texas Hill Country, morning dew on the glass, nice to have working defrosters, so you can see the car behind you.

Why would you want to see that POS Hyundai behind you?

[edmayo]

Because there has been a time or two where I realized that some "POS" behind me wasn't going to stop in time and I had to take evasive action!

[PeterM1965]

Edmayo, I also drive my car reguarly, in the rain and other inclement weather.

Until recently I only had the rear defroster tubes on my 68 but they did not have the foam hoses nor were the holes plugged. At highway speed enough air from the engine compartment is forced through the tubes to defrost the rear window. So in a pinch you will get defrosting without the foam hoses, but not below about 3K RPM. You also get a nice oily rear window!

If originality is not paramount you can always retrofit a 69 and up window with electric defrost.

Peter