Fixing wiper issue with snow

[diesel4me]

A trick an old timer taught me that helps is to use something to prop up the rear of the hood slightly,like a rubber eraser or piece of heater hose,so the rubber seal between the cowl and hood wont seal,this lets heat from the engine and radiator fan blow back onto the windshield..

On my '71 GMC plow truck, it had lost the rubber seal long ago,and the hood was slightly bent up in the rear,like someone shut it when something was in the cowl area ,so that didn't have much problems with snow build up,plus the heater in that thing just about threw flames !..

I had to do that a few times during our nasty Nor'easters that often have 3+" per hour snowfall rates and 60+ mph winds--my diesel plow truck wont always blow hot when its idling or run slow,but will when you start pushing snow and load it down.....but every trick in the book doesn't always prevent you from having to get out,and manually remove the snow build up sometimes,under those extreme conditions !..

 

[campfire]

A trick an old timer taught me that helps is to use something to prop up the rear of the hood slightly,like a rubber eraser or piece of heater hose,so the rubber seal between the cowl and hood wont seal,this lets heat from the engine and radiator fan blow back onto the windshield..

On my '71 GMC plow truck, it had lost the rubber seal long ago,and the hood was slightly bent up in the rear,like someone shut it when something was in the cowl area ,so that didn't have much problems with snow build up,plus the heater in that thing just about threw flames !..

I had to do that a few times during our nasty Nor'easters that often have 3+" per hour snowfall rates and 60+ mph winds--my diesel plow truck wont always blow hot when its idling or run slow,but will when you start pushing snow and load it down.....but every trick in the book doesn't always prevent you from having to get out,and manually remove the snow build up sometimes,under those extreme conditions !..

Hadn't heard that before, sounds like a neat idea. Thanks for sharing!

 

[dyeager535]

Snowed again. This time at freeway speeds, above freezing, so large flakes. Majority melted on windshield, so significant amounts of water flowing down the window on each swipe, but not enough to melt what was accumulating:



It was almost to the point of not allowing the newly-installed wiper motor to park, which I am sure puts undue stress on the motor and linkage. Going to have to fix this issue. Thinking about creating a small diverter to direct some of the duct heat over to that area, but I don't think it will be enough. This just doesn't happen often enough for me to test any time soon.

Due to curvature of the windshield, I can't think of a good way to utilize the handlebar heater and ensure it makes good contact with the windshield, but I think the direct application of heat would work far better than trying to use heated air to do it.

 

[Carcinogen]

So weird. Mine does not do that, although it takes a minute to defrost that center section. Mine has a dash pad though, which might help direct the flow a little. The pad has some baffling, for lack of a better word, to direct the airflow

 

[dyeager535]

So weird. Mine does not do that, although it takes a minute to defrost that center section. Mine has a dash pad though, which might help direct the flow a little. The pad has some baffling, for lack of a better word, to direct the airflow

Can you tell me if yours actually angles the airflow over to that area? I have no idea if there are differences, but my unknown 80's vintage dash pad seems to be just a square pattern, no thought except straight up.

 

[campfire]

Mine does not have this problem. We had (and are still having) a pretty good snow storm today (8-12", 2"/hr snowfall rate), and I made a run to town toward the beginning of it. No issues defrosting (starting from a frozen windshield and parked outside). As the snow fell, the windshield continued to stay warm, and the snow flakes melted fast enough for the wipers to keep the windshield clean.

Tried to get some pictures, but they turned out quite blurry. This one is a couple of minutes into the drive. You can see that not all the windshield accumulation has melted yet, but the wiper path is clean.






I don't see a dashpad in your picture. Are you actually using your air baffles, or is the duct hanging loose?

 

[Can Can]

This simply looks like winter to me?????? We deal with snow below the wipers for 5 months a year. Worse yet, imagine your steering wheel being cold to the touch for over 30 minutes every time you drive your rig.......

 

[1-ton]

You could look and see if the hood cowl area is clogged with dirt and leaves. The hood cowl area is supposed to feed hot engine bay air to the lower windshield area.

 

[dyeager535]

I do need to clean the cowl area out, the design is terrible IMO, and the truck gets coated far more with fir and cedar "needles" than it does snow, so I'm sure there is junk in there. The only heat would be radiated though, correct? No inlet from the engine bay?

Yes, no dashpad, but the vents are hooked up and do direct air properly. No large leaks that might reduce flow over the window either. Even with defrost on, other than directly above the vent (a very small area) the windshield wasn't even luke-warm to the touch. Engine was running 195+.

Anyone got outlet vent temps with heat on full? I put the heater core in long ago, back when ill-fitting ones didn't exist, but it's possible the outlet temp is a factor. This has been going on for years though, it's not a recent or building problem.

To not make people read back a bunch, I'm using longer than stock wipers, maybe 1" more per blade. Largest that fit without hitting anything in any case. Can't imagine that extra swept area results in my problem.

At least if this happened all the time, it would be easier to correct. I am happy that my wheel isn't cold for half an hour lol. Subaru's are one application I've seen that use a heater matrix in that area, so I assume in very cold areas it's somewhat of a problem. I'm not in that climate, but with moderate to heavy snowfall, this happens almost instantly.

 

[campfire]

I do need to clean the cowl area out, the design is terrible IMO, and the truck gets coated far more with fir and cedar "needles" than it does snow, so I'm sure there is junk in there. The only heat would be radiated though, correct? No inlet from the engine bay?

Yes, no dashpad, but the vents are hooked up and do direct air properly. No large leaks that might reduce flow over the window either. Even with defrost on, other than directly above the vent (a very small area) the windshield wasn't even luke-warm to the touch. Engine was running 195+.

Anyone got outlet vent temps with heat on full? I put the heater core in long ago, back when ill-fitting ones didn't exist, but it's possible the outlet temp is a factor. This has been going on for years though, it's not a recent or building problem.

To not make people read back a bunch, I'm using longer than stock wipers, maybe 1" more per blade. Largest that fit without hitting anything in any case. Can't imagine that extra swept area results in my problem.

At least if this happened all the time, it would be easier to correct. I am happy that my wheel isn't cold for half an hour lol. Subaru's are one application I've seen that use a heater matrix in that area, so I assume in very cold areas it's somewhat of a problem. I'm not in that climate, but with moderate to heavy snowfall, this happens almost instantly.

FWIW, my cowl is full of needles. I'm using 18" wipers (vs. the 16" that is stock for these trucks). I don't have a temperature reading, and it depends on the air inlet temperature, but your fingers should be quite warm when you stick them in the air stream. Once the truck reaches steady-state, it should be warm enough that you don't wanna leave them there indefinitely.

I live in a cold-steering-wheel climate, and that's the biggest thing that puzzles me. You don't have nearly enough winter to warrant heating issues. I've had no problem defrosting my truck at -20*F (though starting the diesel in the wintertime can be a whole other issue ). And, as Can Can said, snow below the wipers is normal during the winter months. That shouldn't cause the rest of the windshield to frost over.

FYI, a good pair of gloves will keep your fingers warm if you ever do move to a cold-steering-wheel climate.

 

[dhcomp]

are you SURE all your HVAC ducts aren't leaking? I had to go back and tape all mine, and it made a HUGE difference.

Also, the there all small diffusers on the outlets in the dash pad, just to spread the heat.

With the HVAC issues on the 2003, i'd MUCH rather drive my 91 in the snow than the Dmax.

 

[dyeager535]

It's definitely "hot" coming out the vents, but it's not hot enough to make me consider moving my fingers. Kind of why I'd like a temp reading if anyone had one, since that's less arbitrary.

It's not really a defrost issue per se, it's plenty for defrost (and removing the condensation inside ) but maybe a lack of more heat is keeping more from melting as it hits? The stuff that piles up is obviously what is coming solely from the wipers moving it. Are most of you seeing the majority of snow melt before the wiper even moves it? I'm leaning more towards a heater core issue, but I'd like concrete numbers to compare to before considering pulling it out. Not one of those "might as well" jobs I'd like to tackle.

I don't have AC, so it greatly simplifies what I've got to deal with. Also, no trim makes it easy to check things like the ductwork. I'll re-verify, but last I did check, there was no substantial issue at the one joint. Obviously they leak somewhat as there is no positive seal there, but it wasn't a large percent that was leaking out. The vast majority is definitely coming out the defrost vents. Blend door and diverter to the windshield/floor is working fine.

What I saw of the diffusers in the dash was that they were just a grid pattern. I couldn't tell that any were angled. Did I miss that?

 

[dhcomp]

I think they were slightly angled, but its been a while since i've had a close look.

I was just trying to make sure your defrost is up to par. Snow piles up on mine just the same as yours.

Wonder how much less effective Defrost without AC is? I know the a/c runs with the defrost, but don't really understand why. Guessing its more of a humidity control aspect?

 

[dyeager535]

I think they were slightly angled, but its been a while since i've had a close look.

I was just trying to make sure your defrost is up to par. Snow piles up on mine just the same as yours.

Wonder how much less effective Defrost without AC is? I know the a/c runs with the defrost, but don't really understand why. Guessing its more of a humidity control aspect?

Yep, you got it, humidity. Not an issue here, but that's due to our relatively low humidity I'm sure.

I've got the HD heater setup too, so I'm theoretically moving more heated air than a standard heating setup.

 

[dhcomp]

What you should do is toss in a remote start setup.
For less than $100, my truck is WAY more comfortable to drive in the winter. Below 10 degrees, sometimes it stalls, but other than that, its unstoppable.

Roll out of bed, push remote starter, walk out 10 min later and knock the melted snow off the truck

 

[Jester1]

Again winter hit and still no problem with the 86. I do get a little ice build up at center of window from parking and water running down to it but ice scraper knocks it right out.

On my 79 and 86 i have installed the 18 inch blades and seems to do a better job of not stock piling snow there. I am thinking cowl and wiper upsize for you as what ice and snow is left melts rather quickly once the vehicle is run for any given time on mine. One of the things I am dreaming up is to remove that dumb ass center speaker and allowing air to rise up from there or duct it a bit in some fashion. On thing i have noticed with mine also is the heat/defroster door doesn't completly cut off air flow to one or the other so I have warm air moving there in one way or another constantly.

 

[campfire]

Yep, you got it, humidity. Not an issue here, but that's due to our relatively low humidity I'm sure.

I've got the HD heater setup too, so I'm theoretically moving more heated air than a standard heating setup.

Our area (along the shores of the Great Lakes) is not particularly dry, and I have never had to run A/C to defrost a windshield. So it's not just in the desert that defrosting works without A/C.

 

[campfire]

It's definitely "hot" coming out the vents, but it's not hot enough to make me consider moving my fingers. Kind of why I'd like a temp reading if anyone had one, since that's less arbitrary.

Yeah, I know that numbers are golden. But I don't have any. And I'm not likely to drive my rig until the salt season ends.

 

[dhcomp]

Our area (along the shores of the Great Lakes) is not particularly dry, and I have never had to run A/C to defrost a windshield. So it's not just in the desert that defrosting works without A/C.

My understanding is that on AC trucks, the A/C compressor runs whenever defrost is on. No choice. So, if you have an a/c truck, i'd listen for your compressor. Bet it is cycling on and off.

 

[dyeager535]

One of the reasons I don't have AC. I don't need it for defrost, I just need the air heated, that works fine. Until this thing goes indoors, I'm likely to be dealing with large drops of water on the windshield as I am just condensation.

My problem rarely happens due to just sitting, almost without exception the snow problem is after the truck is warmed up and I'm driving. It just doesn't melt off the windshield as fast as the wipers move it. At this point I'd have to stop, get out, and reach across as best I can to remove the large chunk of snow/ice. Not happening on the freeway! But since the last wiper motor park position got screwed up, I'm attributing that failure to the wipers being forced against that pile every time they swiped. I don't want to cause that again.

I was in snow maybe 10 minutes when that picture was taken (and in that picture it had just stopped), other occurrences have been with lower temperatures, but the result is the same.

It's not like this is a life or death issue, I rarely deal with snow, but that's part of the problem. Any changes I make aren't going to proven for some time.