fan under the back seat

Is the fan 12V DC? If so, you may need to properly plan/design where you draw the air from. You don't want to pull warm air across the engine...

JM2C

-- Mel P.

...............I tried one of those things many years ago and found that it wasn't effective. Tight leakproof connections from the heater boxes forward to the outlet ducts are what's needed. If there's any leakage between that fan and the heater box, it'll make things worse than if you didn't have it because it'll suck cold air into the heating system.

Kind of on the same topic.. does anyone have any old "home remedies" for coping with the heating system fogging up the windows?

I spent some time recently, knowing that cold weather is coming, and sealed up the accordions to try and keep the tubes dry. Few days later it was quite rainy out, and to test it out I opened things up, and par for the course all the windows fogged up.

I've always assumed the beetle does this because moisture collects in the tubes and when you turn the heat on, the heaters evaporates the water and quite cheerfully condenses it on your windows. Once the moisture is gone, the windows properly defog.

This doesn't really bother me, really, and I have pristine grease-free windows so a quick swipe of my chamoi sponge clears everything right up, but I've always been curious if anyone's ever found a way to limit this effect.

.....................The real manly men from upstate NY like myself open the glass vents and roll down the windows until the heater/defroster gets hot enough to stop fogging the glass. Also, when it's below zero Fahrenheit, to prevent our breath from contributing to the problem, we stick our head out of the window but when you get over 60 mph it's hard to drink coffee and smoke a cigarette and use the cell phone all at once unless you can shift gears with your right knee.

I have experimented with several different fan configurations. Only one has worked, and it works really well.

In the end, I installed a BILGE BLOWER FAN (available at any marine engine store) in the flexible hose that runs between the heat exchange and the body. Its important to put it here for two reasons:

1. It doesn't make very much noise in that spot. I have had fans under the seat, and they are really loud, although still very effective at pushing and pulling lots of air.

1. It pulls a huge amount of air from the heat exchanger in this position. I've tried fans in the engine compartment, and it just doesn't make it any better than the stock setup.

The engine fan pushes the air into the heat exchanger, and the bilge blower pulls it out at an incredible rate.

The amazing thing is, they don't melt. I have had the fans running and I would put my hand over the heater outlet at the back seat. It was so hot, I couldnt hold my hand there for more than 3 or 4 seconds, I was scared I would get burnt. That plastic must have a high melting point.

I used the rear window defogger circuit since it already had a relay and a switch conveniently mounted.

At first I only used one bilge blower, on the drivers side. But now I have one on each side, and its amazing how quick it can clear the windshield.

The bilge blower fans are the 3" variety and are 140 cfm each. Make sure your heat exchangers and muffler connections are in good condition, since any exhaust leaks are really noticable with this fan sucking in all that air. I was breathing exhaust air when I first set this up, but I fixed the leaks and its fine now.

The only time I use my bug is in the winter time, when its really cold. I do have a gas heater, and I rely on that quite a bit. But if you seal up the fan really good on the hose (cut out about a 4" section, then use tons of duct tape to seal it.) is unbelievable how well it works.

I have done that, but I've found that by that point it's usually warmer to leave the heater off and keep the windows closed. ;)

Make sure you dont have a leaky front window or leaky hood. Both can leak down into the A channels where the tube from the heater channel comes up and attaches to the vents in the dash. If they get soaked they can steam up the windows...and water in the A channels is very bad. Tim

Look here:

-- Dave "Busahaulic" Pearson Fall City, Washington Remove obvious from addy to e-mail

configurations. Only one has

any marine engine

exchange and the

had fans under the

effective at pushing and

in this position.

doesn't make it any

the bilge blower

running and I

It was so hot, I

was scared I

point.

had a relay and a

side. But now I have

the windshield.

each. Make sure

condition, since

sucking in all that

but I fixed the

really cold. I do

you seal up the

then use tons of

box, it'll make

suck cold air into

"home remedies" for

coming, and

Few days later it

up, and par for

moisture collects in the

evaporates the water and

moisture is gone,

pristine grease-free

everything right up,

way to limit this

That sounds good, you don't happen to have a picture of your setup, right? Ant

Ryan Lester wrote:

What sort of CFM should I be looking for ?

James

Buy a small 12 volt heater that plugs into the cig liger to defog the windshield. I have seen them at harbor freight and in catalogs.

Bruce Amatuer radio is fun! Listen to Gary Clark mornings on Oldies 103 WRKA.

Both have brand new seals, less than 6 months old. After all this surgery the fogging has been reduced by quite a bit, which is good in my book.

Most of my time working on the car this summer was spent dressing up the poor thing after 37 years of abuse under the California sun so it can survive the next 37 years suffering under Chicago humidity and salt. ;)

My biggest worry is the rust, probably suicide to drive it in the winter out here but life really hasn't given me much choice in the matter.

Sorry, no pics.

But the installation is very simple. Basically, I took the Atwood 3" bilge blower which is around 5 or so inches long, and cut out a section of the flexible duct hose the same length as the fan. I put it in the straightest part of the hose, close to the heat exchanger. Then use duct tape to seal it up.

Works like a charm and if you turn off the fan(s), the engine fan still blows the same amount of air through as it did before, so you can use that as your "low speed".

Its the Atwood 3" Bilge blower with 135- 145 cfm. Cant remember exactly what the cfm was but it was in that range.

I wanted to find a picture of what the blower looks like, and here's what I found via a google search:

And regarding mounting, here's what I think you said (in my own words):

You cut out a piece of the stock flexible hose that sits between the heater box (heat exchanger) and the body. This is in *front* of the engine (front is front).

You then inserted the blower inline into that hose and secured it basically with lots of duct tape. That tape is 1) sealing the hose-to-blower connection, and 2) holding the blower in place, including the weight of the blower.

The wiring is connected to the rear window defogger circuit. The defoggers don't work anymore anyway, so why not? Good call.

One other question: When the blower is off, it doesn't impede the flow of air from the engine fan at all?

-Rob

Ryan Lester wrote:

See inserted text below.....

That is the exact unit. The 3" unit is the easiest to install and its around

As for mounting, you have it right on the money. Basically substitute a chunk of the hose with the blower fan. The duct tape both seals it up and holds it in place.

Yep, that worked like a charm.

It doesn't seem to slow it down, at least I can't tell a difference. When I had only one on the drivers side, the passenger side didn't seem any different. I imagine the fan spins a bit with the air being forced past it.

With the fans on, if the engine is above 1500rpm, it blows this massive amount of HOT HOT air out from under the back seat. If you direct the air to the defrost, its not nearly as hot, but it still pushes a lot of air. My car is rusted so bad the heater channels are exposed to the cold air, so I imagine a lot of heat is lost there. If you had a rust free bug, with no air leaks, this system would work really well.

I use my bug in the winter to plow the driveway (for pics go to

I sawed the mounting bosses off the Atwood unit and did a little grinding to make it fit where I needed it to. Very inexpensive and very effective modification. See my previous post for West Marine link.

One fan hookup, that seems to work well, is a 12 volt fan from