A/C Clean?

[Dropped88]

You can add a screen to back side of cowl plastic like the gmt800s which would help keep junk out.

And you really wouldnt want to add a cabin air filter to a gmt400 since realistically they just push just enough cfm to be Ok but if you add a filter it'll make a restriction and wont blow as hard. Same way on a 99-02 (03 + no filter again)gmt800 take filter out and it blows a considerate amount harder then with a brand new filter. So add that to your 400 and it'll be worst

Screen cowl for big stuff and make a filter from quilt batting or something similiar to put over recirc. Air inlet and be done

 

[BonestockK1500]

On 94 and earlier there’s really no way to access this stuff (blower/evap/heater core area) without basically removing or at least loosening the entire dashboard, is that correct?

I had some initiative to clean the blower area once and about the time I found myself with the PCM out laying on the seat just to get to the bolt that secures the plastic cover for the blower I thought, this is the dumbest thing GM did to these trucks. I gave up , put it back together and went fishing instead.

seems to be a huge pain in the ass to access that area.

 

[bugdewde]

You can add a screen to back side of cowl plastic like the gmt800s which would help keep junk out.

And you really wouldnt want to add a cabin air filter to a gmt400 since realistically they just push just enough cfm to be Ok but if you add a filter it'll make a restriction and wont blow as hard. Same way on a 99-02 (03 + no filter again)gmt800 take filter out and it blows a considerate amount harder then with a brand new filter. So add that to your 400 and it'll be worst

Screen cowl for big stuff and make a filter from quilt batting or something similiar to put over recirc. Air inlet and be done

Once everything has been cleaned and "fixed" .... this seems the best preventative measure.

 

[Eveready]

OK I admit it I am a lazy SOB. It probably has to do with the fact that I older too. (not THAT old but old enough!) After thinking about it I took the truck in to a trusted shop and left instructions for sorting and charging the AC, changing the blower motor which just started squealing even on "high" (specified Delco blower motor). It ain't gonna be cheap but I will be riding around in a truck with good AC this Summer. The money will only hurt for a little while and my family needed to be on a diet anyway!

Yes I could have DIY'd the job but that is where the lazy part comes in.

 

[PlayingWithTBI]

Here's one for ya. I ran short on lumber for a couple cabinets I'm building, so I got in my truck and drove the 42 miles one way to get 2 boards of clear alder (what a waist of fuel). It was about lunch time so I stopped at a local stop-and-rob, picked up a couple 24oz Dos-XX and a beef stick. I was eating the beef stick and washing it down with my beverage (I didn't do it, nobody saw me do it, you can't prove nothin') when I had to hit the brakes pretty hard. The other adult beverage rolled off the passenger seat and fell on the floor. It's kinda hot today, ~107* and I had to turn my fan up to high. After a while, I still wasn't comfortable, I looked down where the other can of refreshment was and noticed the plastic bag was sucked up in the blend door vent near the passenger side kick panel and blower motor. Needless to say, I got off the next exit and removed that bag. Now it's blowing cool and I enjoyed the rest of my ride home, LOL. Anyway, I got proof my blend door works when I have the fan on 2nd or high!

 

[alpinecrick]

Here's one for ya. I ran short on lumber for a couple cabinets I'm building, so I got in my truck and drove the 42 miles one way to get 2 boards of clear alder (what a waist of fuel). It was about lunch time so I stopped at a local stop-and-rob, picked up a couple 24oz Dos-XX and a beef stick. I was eating the beef stick and washing it down with my beverage (I didn't do it, nobody saw me do it, you can't prove nothin') when I had to hit the brakes pretty hard. The other adult beverage rolled off the passenger seat and fell on the floor. It's kinda hot today, ~107* and I had to turn my fan up to high. After a while, I still wasn't comfortable, I looked down where the other can of refreshment was and noticed the plastic bag was sucked up in the blend door vent near the passenger side kick panel and blower motor. Needless to say, I got off the next exit and removed that bag. Now it's blowing cool and I enjoyed the rest of my ride home, LOL. Anyway, I got proof my blend door works when I have the fan on 2nd or high!

Too funny.........

 

[alpinecrick]

To add to this.....

Yesterday the heater control valve split on my 96 Express. It's plastic..........and is mostly hidden behind the accumulator and HVAC box. Which necessitated removal of the blower and front of the HVAC. On a van it's all out on the firewall--nothing like the trucks. Took most of the day to remove, find the replacement part and get it back together.

The evaporator is in the box and I had the opportunity to clean it out, it can be partially pulled out of the duct. Besides debris caught in the fins, there was 2-3 inches of debris in the bottom of the duct that probably blocked 15-20% of the evaporator.

There were TWO sets of stainless screens, one attached to the backside of the evaporator and another further into the duct.

My friend down the road is a commercial refrigeration tech and a Ford guy (I like him anyway), so I texted and asked what is the best stuff to clean the evaporator. He was on his way home, stopped by and handed me a can of this:
https://www.amazon.com/Nu-Calgon-41...+18+oz+Evaporator&qid=1593211338&s=hpc&sr=1-3

He said spray it on and let sit 10 minutes and rinse. The foaming Blackhawk stuff actually caused a lot of the debris buried in the fins of the evaporator to back out, and then I could just barely stick my hose behind the evaporator and push that stuff out. I did it three times and got it fairly clean.

I ordered some and I'm going to try it on the condensers of a couple of my vehicles.

 

[Schurkey]

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.

It's a centrifugal blower. Doesn't matter which way the motor runs, it's going to blow the same direction. Only difference is that one direction will be "efficient" and flow lots of air, and the other direction will be "Piss-Poor air flow, inefficient".

 

[alpinecrick]

It's a centrifugal blower. Doesn't matter which way the motor runs, it's going to blow the same direction. Only difference is that one direction will be "efficient" and flow lots of air, and the other direction will be "Piss-Poor air flow, inefficient".

In other words, if the squirrel runs backwards in the squirrel cage it won't move much air..........

 

[Donald Mitchell]

I added a filter at the intake under the cowl. It used a piece of fiber and charcoal filter like goes in your return air in your house and made a holder for it to fit the opening. It does not restrict the airflow but keeps all the junk out.