andyr354

It is just not keeping up. The passengers side is not getting much at all, the drivers is marginal. I can't keep ice off the windshield while driving and have to stop occasionally to scrape it.

I flipped down the glovebox like read in some other posts and here is what I can see.

The door all the way over to the right pulls shut and closes the inside air intake
The other vaccum pod in the middle pulls on both heat and defrost.
the cable to the mix door from the dash is working ok and moving the door.

Where is the door that either directs to the defrost or heat? I was just looking at it for a short time over my lunch and didn't have much time. There is still some air blowing from the heater vents while on defrost, but not alot.

Is there a connector between the defrost duct and the heater box? Maybe there are some papers or other trash in there that have fallen down in the vents.

Just asking of anybody who may have been in there, it is to dang cold to mess around all day with it.

greatwhite

i believe that the biggest culprit is that these engines run so cool that there just isn't enough heatto strip off and use. Blocking off your rad will help. Your op temps won't go up, but your heater output will. The old way was that on defrost 80% of the air went to the w/shld, 20% to the floor. Heat was the other way around, 80% to floor, 20% to w/shld. Now I think it is 100% to selected area. Choice of vision, or circulation in your feet. But mine will keep the w/shld clear in -30 and lower at highway speeds. Just don't expect much heat at low speeds around town if its not working. Blame it on your great fuel economy. Not enough fuel being burned to create enough BTU's for the water to carry to the heater core to keep your windshield clear. Thats my theory.

Then again if you have heat but no airflow, I'd check for something in the vent, or tubing if it seems your doors are all moving air where they're sposta.

uncleroty

Sounds to me like you may have a mouse in the house. Sometimes they make a nest in the duct work, and you get a problem like that. Mine heats up just fine in about 20 min idling and the temps where I am got to -37 with the windchill.

It especially sounds like it because I've noticed that my windows clear both sides at relatively the same rate. As suggested by greatwhite, check that everything is moving the way it's supposed to, and maybe take it apart and check for stuff inside. it's a pain in the behind, but better than not seeing where you're going.

Good luck with it.

wannadiesel

Like Uncle said, I suspect mice. When I bought my old '85, I found that the entire heater box was full of the firewall insulation. Defrost worked much better once I cleaned all that out.

ChrisLib

Is this what yer talking abuot wannadiesel?.
http://ramchargercentral.com/boards/...owtoshow;id=45
I did this on my 86 and it did alot for airflow, worth ck`in out.

wannadiesel

That's pretty cool! I wish I had thought of just hacking the box open, I actually took it apart. It was a beater truck, so there was no reason to try to keep it looking factory. This was actually the wool/felt off the back of the firewall cover and floor mat, chewed up and made into a nest, not just trash and dust that got sucked in the cowl.

andyr354

Hate to cut a hole, but might have to do it. Would suck to have to pull the entire assembly.

But I seem to have decent airflow while on vent or AC out the dash vents. Guess I will compare it to my dads 90 and see how it is.

jiMMyCTD

**** that link is exactly what i need to do. i know i have leaves inmine. when i turn it on you canhear the russling over there and some come out. ive been snagging them with needle nose when i see them close by, im sure the fins are even worse.
ill bust out my all in one cut tool my pops got me with the flexi shaft to cut that.

jiMMy

Den

I need to tear into my dash and work on the switch system itself. The 2 highest settings on the fan are the same. No max fan..it's the same as the one before it


Den

mopar2ya

I bought some snazzy Lund grill inserts to reduce the airflow to the radiator,and I cut the grill inside for the recirculation and cleaned a ton of leaves from around the evaporator whcih allowed more air to be pulled in and through the heater core. Then I covered it with door screen.

hippie

I have a 93, I cut a square hole in the hearter box so I could clean it out. I clean it every year, you would be suprised what you will find in there. I cut a pice of metal that's a little bigger than the hole Painted it and put gasket on the back side. I Put enough holes along the outer sides of the cover so that when you replace it it will seal. I also used self taping screws to hold it on. I'll take a pic of it tomorrow and post it...

andyr354

Thanks. I think I will have to try this. I think I will get one of those little router like bases for my dremmel and use it to cut the hole nice and clean.

What did you use for gasket material? Cork or some type of foam or rubber?

hippie

I used some flat thin rubber. after I glued it to the cover plate I cut out the screw holes. Good luck on the project...

cLAYH

I replaced my thermostat with a NAPA one and found it helps keep the engine temps up higher in the winter. Come towing season the Cummins one goes back in.

Apparently the NAPA one starts to open at a higher temp than the Cummins one. Both should be fully open at the same temp.

Last winter with the Cummins one I could not keep the windows clear. This year with the NAPA one there is a noticable improvement.

I also have a aftermarket temp gauge that I installed last summer. The NAPA t-stat the engine seems to run about 5-10 degrees hottor than with the Cummins t-stat.

I also run Lund grill inserrts in the winter to block airflow and have a non-LE model so no interior insulation.

At -30C with just myself the windows stay clear. With the wife and baby in the truck the side windows start to ice up. Last year I couldn't keep the side windows clear at anything below -25C with just myself in the truck.

andyr354

I can't melt windshield ice at 15 degrees above with a new thermostat and lund inserts.

EDIT: guess you are probably talkin celcius since you are north of the border though.

Just barely any air out the defrost vents, though it is decently warm.

While in the hardware store picking up a dremmel bit I saw what might make a nice hole plug. Got a dual gang outdoor outlet blank. It is the right size I think and came with a gasket in the package. Just need to paint it black.