Merle Coggins Posted July 23, 2013 Report Posted July 23, 2013 Yesterday on my way home from the WPC meet I had to drove through heavy rain for about 180 miles. I found that I still have some sealing to do on my windshield gasket. But the biggest problem was from the windshield fogging up so bad that I couldn't see. I had my Arvin heater on high trying to get as much defrost air as possible, but it couldn't keep up. The extra moisture inside the cab from the leaking windshield probably didn't help. I had some napkins handy that I used to continually wipe the glass so I could see. If the rain would let up some it would get better, but when it rained hard the fogging would get worse. I finally stopped at a truck stop and bought a clip on 12v fan, which I clamped onto my steering column so it could blow steady at the windshield. Since I have a 12v power socked wired to my 6-12v converter I was able to power it. That helped to keep the window clear enough to get home. So, does anyone have a defrost/defog fan mounted in their truck? If so, could you post some pictures? I'm thinking about finding a "vintage" 6 volt fan to mount on the windshield header to be used in these situations. It would probably come in handy IF I ever do the Cali trip. Merle Quote
Jeff Balazs Posted July 23, 2013 Report Posted July 23, 2013 Hi Merle; As you know my truck is not on the road yet......but this is a situation that I have been concerned with for some time. I can imagine how you felt. Driving with a fogged up windshield is miserable at best and almost always extremely dangerous. I am hoping that the provisions I have made so far will cope with this sort of situation. I have added the optional fresh air kit complete with cable operated shut off valve. This feeds through a reconditioned Mopar Model #65 heater that has the cable operated diverter valve that redirects the flow of air directly to the defroster vents. As part of this installation I made gaskets to help keep all the air coming into and generated by the fan inside the ducting. I also used rubber weatherstrip material to line and seal the inside of the interior windshield trim piece so that the air going to the two vent slots would actually be forced through those vents instead of just anywhere around the glass. I can't say for certain that this works perfectly yet......but I have to think it is going to be a whole lot better than the little aftermarket heater and no fresh air intake that I started off with. Jeff Quote
JBNeal Posted July 23, 2013 Report Posted July 23, 2013 I think the trick is ya have to crack the vent windows open a li'l bit so that there is less of a dew point gradient inside the cab. I've driven a car where the AC didn't have a charge, so when I would set it on defrost, the windows still fogged up cuz I was blowing warm moist air onto the cool glass Quote
Don G 1947 Posted July 23, 2013 Report Posted July 23, 2013 Merle, Don't want to hijack this thread, but can you tell me a little about the 6/12 volt converter you have? Seems I remember seeing a Trico vacuum fan on ebay. Probably more of a drain than a help, but kind of neat. Don Quote
Don Coatney Posted July 23, 2013 Report Posted July 23, 2013 That is the reason I always carry a towell in the cabin of my car. Quote
1950 Special Deluxe Posted July 23, 2013 Report Posted July 23, 2013 Yesterday on my way home from the WPC meet I had to drove through heavy rain for about 180 miles. I found that I still have some sealing to do on my windshield gasket. But the biggest problem was from the windshield fogging up so bad that I couldn't see. I had my Arvin heater on high trying to get as much defrost air as possible, but it couldn't keep up. The extra moisture inside the cab from the leaking windshield probably didn't help. I had some napkins handy that I used to continually wipe the glass so I could see. If the rain would let up some it would get better, but when it rained hard the fogging would get worse. I finally stopped at a truck stop and bought a clip on 12v fan, which I clamped onto my steering column so it could blow steady at the windshield. Since I have a 12v power socked wired to my 6-12v converter I was able to power it. That helped to keep the window clear enough to get home. So, does anyone have a defrost/defog fan mounted in their truck? If so, could you post some pictures? I'm thinking about finding a "vintage" 6 volt fan to mount on the windshield header to be used in these situations. It would probably come in handy IF I ever do the Cali trip. Merle Here are a couple of pictures of the defrost fan that 1940 Plymouth (Bob D) sent me a couple of years ago. I have cleaned it up and re-did the wiring. It runs great, once I get the rest of the truck operational I will mount it on the steering column. Quote
P15-D24 Posted July 23, 2013 Report Posted July 23, 2013 I have a Trico vac fan mounted in my B1. You can see it between the visors in the pic. It helps. Cracking the vent windows is good. Most of the aftermarket Arvin heaters (and others) have a defrost mode. You need to close the downward facing heater vents so the hot air is redirected into the windshield defroster tubes. I'm in the process of installing the fresh air heater (one with an air inlet at the front by the radiator) and I'm pretty sure that will fil the problem. But I will also have a towel close at hand on rainy days. Quote
Merle Coggins Posted July 23, 2013 Author Report Posted July 23, 2013 I did have the driver's side vent window open as far as possible without letting in more water. I tried closing it once and it got worse. GT, that fan looks pretty small, but that's kind of what I was thinking about. Have you used it for defogging? I'll have to look at my heater again. If I could have blocked more air from the main outlets it would have forced more air to the glass. I don't remember there being a door for that purpose, but I'll have another look when I get a chance. Otherwise I may have to carry a roll of duct tape to tape off the heater outlets. Merle Quote
MBF Posted July 23, 2013 Report Posted July 23, 2013 In my 36 Plym, I have a steering column mounted fan (with rubber blades). With the heater on, it will keep the driver's half clear. In the trucks I have the original defrosters, but there doesn't seem to be much air movement from the windshield frame, so on the dash I have a caged fan mounted that I can aim where I need it. Mike Quote
Don Coatney Posted July 23, 2013 Report Posted July 23, 2013 Several years ago a forum member gave me this period correct 6 volt rubber bladed fan. I did not use it so I gave it to another forum member. They are out there if you look. Quote
wallytoo Posted July 23, 2013 Report Posted July 23, 2013 (edited) the fresh air kit in my truck works very well. i also crack the vent windows. i haven't added any extra "insulation" around the window trim piece. still, the defroster seems to do a good job keeping the window clean. the windshield rubber doesn't leak, which does help. we've had plenty of rain in the last year for lots of testing opportunities. just in case, i carry a small squeegee, about 7", in the glove box. i also carry one in my jeep cj, which i have to use a lot. much, MUCH better than a towel. stop using a towel, you'll be happier with the results. edit: for clarification, my truck has the complete "fresh air" kit, with screened intake at the grille, 4.5 inch duct hose, control valve to close off fresh air, and the heater with driver's side defroster ports. wally Edited July 23, 2013 by wallytoo 1 Quote
Alshere59 Posted July 23, 2013 Report Posted July 23, 2013 I have to agree the squeegee is the way to go. Faster and keeps the streaks away. Quote
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