Need help on Insulating my truck

[L35THERNECK]

Whats up! I got an '85 720 and Im getting tired of scraping ice of the INSIDE of my windshield. I need some info on what to use for insulation and where to use it. My friend was checking something out in the wheel well flashing a light around and being in the driver seat I saw light coming through onto my leg... Any help would be appreciated!

Thanks for reading.

  

[datzenmike]

Frost on the inside of the windshield is from wetness inside. Could be from slush or snow on your boots to a hole in the floor to a leaking windshield. What happens is while driving the interior warms up and the water evaporates from the carpet into the cabin air. When you get out and the vehicle cools down it condences on the cold inner glass. No amount of insulation will fix this. Keeping water out is the only answer. Try those floor mats that collect water or remove the mats regularily and dry them.

 

When I get out of my Datsuns and it's cold outside I leave the door open for at least 30 seconds while I put my keys away or get whatever out of the back. Two doors open is even better. The warm moist air is expelled and the interior cooled down. The longer the better and it really works.

[jvb5577]

You found your problem.. FIX THAT HOLE in the wheel well.  Then as stated above.  I always roll my window down just before I get home, seems to help with any moister that is in there since my window won't fog up then.

[Fat510]

patch the hole. maybe make some sort of carpet to lay down around the cab later if you don't have any

[L35THERNECK]

Frost on the inside of the windshield is from wetness inside. Could be from slush or snow on your boots to a hole in the floor to a leaking windshield. What happens is while driving the interior warms up and the water evaporates from the carpet into the cabin air. When you get out and the vehicle cools down it condences on the cold inner glass. No amount of insulation will fix this. Keeping water out is the only answer. Try those floor mats that collect water or remove the mats regularily and dry them.

 

When I get out of my Datsuns and it's cold outside I leave the door open for at least 30 seconds while I put my keys away or get whatever out of the back. Two doors open is even better. The warm moist air is expelled and the interior cooled down. The longer the better and it really works.

 

This would apply to a foggy windshield also? After I scrape all the ice off its starts to fog up at Ill have to drive around for at least 10 -15 mins. 

[datzenmike]

Yes but could be your breath also if the defrost is not on or warm enough. I find on really cold days, turn the fan on high so you breath is blown away from the glass and drive with the window slightly open to draw any humidity away until you get some heat happening.

[cruznude]

warm up vehicle before you just start and drive. duh?  Then turn on turn on defrost and don't forget to crack window for some air circulation.  But first patch up hole.

[qwik510]

Not sure if the 720's had it but use the fresh air vs. recirculate switch. Bringing in fresh air helps cut back on foggy windows when it's cold outside. My D21 has this feature and it fogs up bad in the recirculate position but not at all in the fresh air position.

[DanielC]

After your temp gauge is working, and you trust it, do this.

Another picture of lower part of radiator in my 521.

 

This is some foil insulation I found at Home Depot,

along with this spray adhesive.

 

After taking the door apart, I put this insulation in the door, like this,

 

to be honest, this is a spare door, and I have not put it on my 521 yet, too cold outside to work on the Datsun.

 

With the cardboard in place, I start my 521, with the heater on cold, wait about two or three minutes, and then start driving slowly, and down hill if possible.  After about 2 miles, the temp gauge is at "normal" and I can turn the heater on "heat".

[datzenmike]

Yes the 720 has recirculate. Not sure why it's used but I wouldn't in the cold. Fresh (warmed) air will be drier usually and displace the humid air in the cab out through the window or the flow through venting.

[L35THERNECK]

After your temp gauge is working, and you trust it, do this.

Another picture of lower part of radiator in my 521.

 

This is some foil insulation I found at Home Depot,

along with this spray adhesive.

 

After taking the door apart, I put this insulation in the door, like this,

 

to be honest, this is a spare door, and I have not put it on my 521 yet, too cold outside to work on the Datsun.

 

With the cardboard in place, I start my 521, with the heater on cold, wait about two or three minutes, and then start driving slowly, and down hill if possible.  After about 2 miles, the temp gauge is at "normal" and I can turn the heater on "heat".

How did you know my temp gauge wasn't working... lol The punk that own my truck before me messed with the vents so they're not that strong and only work for the windshield. Thanks!!! 

[L35THERNECK]

Yes the 720 has recirculate. Not sure why it's used but I wouldn't in the cold. Fresh (warmed) air will be drier usually and displace the humid air in the cab out through the window or the flow through venting.

God damn it I've only been using recirculate cause it seems to have a little more kick to it. Thanks again!  

[qwik510]

God damn it I've only been using recirculate cause it seems to have a little more kick to it. Thanks again!  

It may have more kick to the heat portion since it is not warming the outside (FRESH) air coming in but when in the recirculate position, the moist air inside the cab is causing the windows to freeze up. Using it in the fresh air position, it will bring in air from outside which is probably drier then the inside air and will help to solve the problem you originally posted about.

 

Datsun and Nissan trucks usually have very good heating systems. If your heat is marginal, you may have other issues. Clogged heater core, bad thermostat, etc. My D21 heater will blast you out of the cab on the lowest fan setting on 30 degree days. 

[datzenmike]

Lack of heat:

 

If you have a 180F swap in a new 190F for the winter. Spend at least $10 on a GOOOOD one. MOST COMMON THING

 

Old thermostat is stuck or part open and engine is slow to warm up. See above. SECOND MOST COMMON THING

 

Drain coolant. Pull the hoses on the engine side of the fire wall and flush the heater core with garden hose and heater in the HOT position. Go both directions several times until water runs clear. This will flush any rust or sediment out. THIRD MOST COMMON THING

 

Look under the cowl into the plenum below the wiper arms. This often fills with leaves and maple keys and will plug up or restrict air flow to the bower motor. FORTH MOST COMMON THING

 

Check dash controls are moving through their full travel. Be sure the HOT position opens the water cock fully. Be sure the flap gate is fully closed and you are not mixing cold air with the warm.

 

Check the the foam rubber seal around the core is good and everything air tight so no warm air wasted and cold air getting in.

 

Check the bellows hose between the blower fan and the heater core for mouse nest or blockage. Run the fan... is there good air flow???

 

Is the coolant low?