Windshield constantly freezeing over.

I've got some Aquapel coming today. Can't wait to try this stuff on windshield, side mirrors and side glass to see if it helps. I know we're talking about ice, not water, but by your logic it should still help.

I'm also diggin' the 'lower the visors' idea mentioned here to trap heat from the defroster vents near the windshield. Nearly 30 years of driving commercially and I've never heard of or thought of that.

 

Keep us posted!

 

Dont know if you have an easy way to do it but disconnect the ac clutch at the compressor. That should get air a bit warmer on defrost, but if your ac is beating your heater core, something is seriously messed up

 

You gotta remember AC isn't always making cold air, AC dehumidifies too. If you've got your temp knob turned up your AC isn't producing cold air necessarily. That's my understanding anyway.

 

Yes but no,

typically the system runs recirc air through the ac core to condense out the water then through the heater core to heat it up for the cab.

Theres no real modulation to the amount of cooling youre doing to the air any time the ac compressor is running, the heat is another matter, while the coolant loop hitting the heater core is at engine temp coming in, that is modulated by a valve that increases or decreases the volume of coolant to the core.

 

I didn’t read every post, I did see. The post about the fans. Trucking in the 60’s almost all tractors had Aux. fans. Hoods had them on the dash, COE had them mounted on the roof above the windshield. I don’t have any idea why this practice went away as the years have passed.

 

Almost all of the trucks now use air doors instead of regulating coolant flow. The doors control how much of the airflow passes over the always hot heater core.

Anyone whose driven an old truck with no AC can tell you that the AC really helps the defroster keep the windows defogged.

HVAC systems have gotten much, much better over the years, reducing the need for the fans. Those old trucks moved so little air (and often no AC to dehumidify the air) that you either had fans or kept a clean rag handy to keep the windows clear.

 

The ac needs 50 psi for the low pressure switch to kick it on.

134 has a tendency to contract. Pressure drops.

I'm not sure on trucks since sleepers hold roughly 4 lbs. My last one was a daycab. 2.25 lbs.

My car holds 17 oz. The compressor don't work below 44*. Pressure drops. In January. My obd2 reads 5 psi.

Semis may have the same effect. May.

17 oz. Is easy to contract. I'm not sure how much 4 lbs. Would contract.

In cars. The compressor isn't even working when it gets cold. 134 wise.

Course. Today. The new thing is 1234. No idea on that one yet.

 

It's was - 8 when I was loading earlier, I forgot to switch off the def/heat blend when I got out. Fan kicked on (high pressure) to remind me I forgot.