A/C Clean?

[div4scpro]

The screen attached on the downstream side of the evaporator everyone is referring to serves one purpose. It helps collect condensation created on the evaporator core in the AC mode and then it runs out the condensation drain for the whole box. Nothing more, nothing less. Believe me I wish there had been a provision for a pre filter before the blower motor to help keep everything from pollen to pine needles out of the air box.
I have good success using the no rinse foam condenser coil cleaners on the evaporator. They are designed to be non corrosive unlike some household cleaners, either too alkali or acidic. Either one can harm the aluminum of the evaporator and or heater core. One product I've used, Lubegard 96030 Kool-it Evaporator and Heater Foam Cleaner, or FJC 5914 Foaming Evaporator Cleaner - 16oz have small diameter spray hoses attached to the can. That makes it easier to direct the foam onto the evaporator core surface in the confined space. Here is another way to use that hose on the can. While you have the box open and the blower motor out you can carefully drill a small hole in the plastic part of the heater/evap box just upstream of the evaporator core. Make sure you already have a rubber plug so you drill the right size hole. This enables you to apply the foam into the evaporator core without any disassembly. You will the also be able to run the small hose in the foam can up the condensation drain to discharge the foam although this is not as precise as the first method. Either way once you have sprayed the foam give it time to stop dripping from the drain then run the AC on Max speed and recirc mode. This creates additional condensation on the evaporator to rinse it. None of this is a substitute for taking out the blower motor and inspecting the surface of the evaporator core and removing anything from leaves, locusts, and anything else that is dead in there. This whole process is also useful to make sure that your condensation drain is not clogged and you don't get soaked carpets later on.
Dont tell my wife but my old water pic o max works great at rinsing the surface of the evaporator core while you have it open.

Long winded but this has helped me never have to replace the heater or evaporator core on a 97 K1500 and it blows as hot and cold as I need it to.

 

[24 Karat Brown]

Considering that the blower motor is just two wires, is it possible to switch them and to turn it on full blast to "backwash" the system? Meaning blow all of the air OUTSIDE the truck to clean out the debris.

 

[alpinecrick]

The screen attached on the downstream side of the evaporator everyone is referring to serves one purpose. It helps collect condensation created on the evaporator core in the AC mode and then it runs out the condensation drain for the whole box. Nothing more, nothing less. Believe me I wish there had been a provision for a pre filter before the blower motor to help keep everything from pollen to pine needles out of the air box.

Now there's some helpful info--thank you!

 

[kennythewelder]

Considering that the blower motor is just two wires, is it possible to switch them and to turn it on full blast to "backwash" the system? Meaning blow all of the air OUTSIDE the truck to clean out the debris.

Best guess, I would say no, unless you wire it direct to a power source and ground. You dont want to back feed the resistor or any of the rest of the system. I just wouldnt chance it. Its not that hard to remove the blower motor and clean out the HVAC box that you can reach into. That is where most of the trash will be anyway. The condinsor core will block out most anything from going past it so the trash should be where the blower fan is anyway. Also I dont think your going to force trash back up into the cowl anyway, but you may force it onto the floor of the truck where the recycle door opens to the passengers floor, maybe.

 

[east302]

The screen attached on the downstream side of the evaporator everyone is referring to serves one purpose. It helps collect condensation created on the evaporator core in the AC mode and then it runs out the condensation drain for the whole box. Nothing more, nothing less.

Here’s a picture of the screen for those interested. The factory glued them to the evaporator.

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[Eveready]

Some kind of screen in the Cowl area might be a decent idea now that we are all agreed that many of these trucks will be kept for generations. Just a simple screen to keep the leaves and such out of the EVAP would likely be worth doing. I have a small camera I intend to use when I clean mine out just get a good picture of what has managed to get in there in 27 years.

 

[alpinecrick]

Considering that the blower motor is just two wires, is it possible to switch them and to turn it on full blast to "backwash" the system? Meaning blow all of the air OUTSIDE the truck to clean out the debris.

Remove the louvered vents from the dash. Be careful, some of the plastic vents are fragile/brittle as it gets older. Take your shop vac and put the hose on the exhaust side and stick the vac hose into the ducts--that will provide a lot more CFM backwash. It probably depends somewhat on the power of your vacuum. I also have a 1" diameter vacuum hose for my sanding tools and I used that to push a ways into the ducts. I did this to my 06 2500HD because it had spent some time in really dusty conditions. Then I used a couple spray bottles worth of Glass Plus and sprayed in to the ducts and both vacuumed and blew them out with both vacuum exhaust and compressed air. I removed the cabin filter when I did this and a lot of it ended up where the filter would sit.

 

[24 Karat Brown]

Best guess, I would say no, unless you wire it direct to a power source and ground. You dont want to back feed the resistor or any of the rest of the system. I just wouldnt chance it. Its not that hard to remove the blower motor and clean out the HVAC box that you can reach into. That is where most of the trash will be anyway. The condinsor core will block out most anything from going past it so the trash should be where the blower fan is anyway. Also I dont think your going to force trash back up into the cowl anyway, but you may force it onto the floor of the truck where the recycle door opens to the passengers floor, maybe.

With the dash in place (I am NOT removing another dash) theres not much room to get to any of that. My A/C system was rebuilt not too many years ago, hence why my blower motor was brand new. They might have replaced the other stuff too. Its possible these trucks just dont have a lot of airflow from factory

 

[div4scpro]

don't be afraid to use the condenser foam cleaning as a preventive method.

 

[NETFREEE]

Back to the original post by 24 karat gold. One thing to check in your system I'd look under the blower case on the passenger side to see if the blower has sucked any plastic or paper up from the floor area. Many times I have discovered that to be the problem with the air flow. Wouldn't that be great if that is the problem.