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the only way to really clean the Evaporator Coil well is removal, and soak in coil cleaner.
you can remove most of the debis in the box, but for full blown effect you have to remove the evaporator.
When I restore Vetts i pull heater cores, and evaporators, and clean, while everything is apart. clean pressure test,
including the new replacement units.
Yep/dump/recover freon. I use spray on Insulation on the inside and outside of the boxes too !
I wonder if someone could call the auto parts stores and try to borrow or rent a bore scope and snake it through the resistor hole to check it out. Saves a lot of work taking it apart and finding it not clogged.
I think Harbor Freight sells a bore scope for little money.
Otherwise doesn't the blend door swing back and forth between the heater and A/C core so could block the A/C core by putting it on heat only to see if it blows any differently through the A/C core to check if that is clogged?
I found the only way to clean this out, without taking 1/2 the car apart was to obviously remove the RF wheel, and cut out the fender liner, remove any overflow tank, and then the blower motor... get a small powerful suck hose in there very carefully down to the evap housing down LO, I used a full size shop vac with 3" hose necked down to about 1.5" so it was screaming,.....and with flashlight and mirror, determined that it was clean.....then looking straight ahead through the blower housing you see that silly outside air door, it's normally open....so go remove it entirely via the bolts in the wiper housing, lift it out and remove the springs on it, reinstall with it in the closed position and seal it shut with a good coating of RTV....go inside behind the pass/right side kick panel, and remove that silly flapper door.....
now to make a pattern on the blower motor, cut out a 3/4" thick piece of plywood to match that pattern so you can drill/cut match it to space the motor out by 3/4 inch....then go buy a early C4 blower/fan combo from O'Reilly auto parts.....
that ground lead off the motor frame, replace it with a 10 gauge wire to the engine block along with the other leads from the fan and wiper motor.....
SO you have superior blow power, increased airflow, and better voltage to the blower.....and it's on constant recirculation, meaning you get no more leaves/crap in the ductwork to block airflow....
CASE CLOSED!!!
don't forget to block that control air line that fed the two valves....
So I'll have to lose all my Freon and disconnect it huh ?
NO...take it to someone who has the AC machine that can suck out your Freon...and then they can put it back in after a vacuum has been pulled on the system.
It is not a good thing to just let Freon out of a system into the environment. I know many do....but I would not advise it.
Also...the half of the evaporator case closest to the engine can be removed...then the evaporator core can be removed after is has been disconnected. The half pf the evaporator case with the blower motor can stay. Some of this removal can be done from the underside. I do not cut on the body.
NO...take it to someone who has the AC machine that can suck out your Freon...and then they can put it back in after a vacuum has been pulled on the system.
It is not a good thing to just let Freon out of a system into the environment. I know many do....but I would not advise it.
Also...the half of the evaporator case closest to the engine can be removed...then the evaporator core can be removed after is has been disconnected. The half pf the evaporator case with the blower motor can stay. Some of this removal can be done from the underside. I do not cut on the body.
DUB
I'm with this guy. Yes, it's always faster to take a saw and cut a hole. But is it the right way? Not for me anyway. This job can be performed without cutting holes, and can be cleaned out via the blower motor access by removing it and working carefully with a vacuum. I have reduced the vacuum hose to 1" id so I could access this area in other cars as well. A previous poster showed a PERFECT reason as to why you might have a restriction. I too did the blower motor mod and addressed this issue of less than acceptable air flow. It involves 10 gauge wiring, a C5 blower, a 1" spacer plate, a relay and a 14+ volt feed from the alternator output. The need for a GOOD ground issue has already been brought up by another poster. This mod offers MUCH better air flow. In addition, if your car was ever smoked in, there are a few extra things that need done, unless you can live with your car smelling like an ashtray. Mine was lived in by a smoker, and though it was always garaged, I had to literally remove both the evaporator and heater core and give them a good acid bath with condenser coil cleaner. Yes. Acid based. I don't want to ever have to smell a 40 year old cigarette in my car. An overnight soaking in a solution that "purple" cleaner followed with a good scrubbing of all interior surfaces of the car when the interior was gutted, and I paid special attention to the areas that carried air, both on the supply and return side before reassembly. For the areas I couldn't reach with a scrub brush, I borrowed an industrial strength Ozone generator and allowed it to run a few weeks in the interior of the car. Great airflow. No bad smells. Good luck!
Since someone brought up cutting the car... What about going to the inside, remove the passenger dash with pocket which is easy. Expose the inner side of the heater box. Cut a 6X6 inch square in that have a good look and clean out that way. Patch it up good. Replace the dash panel. No possible visible evidence until someone started to take the car apart. Would take 30 minutes of easy access work. Done
Getting back to your original request "I want a LOT more air flow from my AC" here is what I did to my 79 to make big improvements. You said you installed a 84 fan blade but didn't mention anything about spacing it out. The 84 fan has more blades that are more aggressively curved but it is also longer. To get the most out of it make a spacer to get the total length inside the blower area. I made mine out of plywood, sanded it smooth and painted it and nobody has noticed it in 14 years. Plus it is not a permanent mod.
Another thing I did was stuff flexible defroster duct1 1/2 inch I think, in the 2 lower side vent tubes and seal them at both ends with foam. What it does is restrict the air in those very large side vents and increases the velocity of the air coming out of all of them, side and dash.
Works great on my 79. Hope this helps.
Since someone brought up cutting the car... What about going to the inside, remove the passenger dash with pocket which is easy. Expose the inner side of the heater box. Cut a 6X6 inch square in that have a good look and clean out that way. Patch it up good. Replace the dash panel. No possible visible evidence until someone started to take the car apart. Would take 30 minutes of easy access work. Done
This idea is fine in 'theory'....if you are wanting to cut and get all that dust in your interior. And even with a vacuum...you will get dust regardless of some degree. Once again... I do not desecrate a Corvette.
ALSO...I have run into so many evaporator cores that have a slow leak...and the core is coated in oil and dust and crap ...and UNLESS you remove it.....vacuuming it out is pointless due to it being plugged up inside the fins.
I also use the vacuum hose method where I step it down to a small heater hose and suck out anything I can get. BUT...even doing that...the shape of the evaporator case is made in such a way where debris can still be stuck in the bottom. YES...it is a small percentage of the overall surface area...but knowing that my OCD kicks in....I feel that it I am going to do it..I might as well do it right. AND I have had the debris in the bottom being a caked mud material due to years of decomposition and moisture getting it wet and drying constantly.
I'm asking where is the opening at that created this mess?
The fresh air (and leaves and dirt) come in through the windshield wiper well. There are screen on either side.
Friday morning I'm going to remove my blower motor and attempt to vacuum and clean the evaporator as best as possible.....wish me luck and I'll report back with and improvements - good or bad
I'll also make up a finer screen for my fresh air intake !
While you have the blower out, also pull the resister from the clean side of the evaporator, stick an air blower with a long bent tip in there and blow air back through the coil while vacuuming the other side, that's about the best you can get it without pulling it apart.
Here's a pic of the fresh air screen
If it's that dirty, I can imagine my evaporator !
To me it looks like you may be ok in there. The screen did what it was supposed to and stopped the large debris. Look at the pic above, clogged with leaves and big things that your screen would not have let in. Do you have history on how it was cared for? Stored outside?
To me it looks like you may be ok in there. The screen did what it was supposed to and stopped the large debris. Look at the pic above, clogged with leaves and big things that your screen would not have let in. Do you have history on how it was cared for? Stored outside?
Don't really know the history except for the 13 years I've owned it.
Now ya got me wondering if I would be wasting my time by pulling it apart.????????
Only one way to know for sure I guess......
07-09-2014, 05:34 PM
Not for me anyway. This job can be performed without cutting holes, and can be cleaned out via the blower motor access by removing it and working carefully with a vacuum. I have reduced the vacuum hose to 1" id so I could access this area in other cars as well. A previous poster showed a PERFECT reason as to why you might have a restriction. I too did the blower motor mod and addressed this issue of less than acceptable air flow. It involves 10 gauge wiring, a C5 blower, a 1" spacer plate, a relay and a 14+ volt feed from the alternator output. The need for a GOOD ground issue has already been brought up by another poster. This mod offers MUCH better air flow. In addition, if your car was ever smoked in, there are a few extra things that need done, unless you can live with your car smelling like an ashtray. Mine was lived in by a smoker, and though it was always garaged, I had to literally remove both the evaporator and heater core and give them a good acid bath with condenser coil cleaner. Yes. Acid based. I don't want to ever have to smell a 40 year old cigarette in my car. An overnight soaking in a solution that "purple" cleaner followed with a good scrubbing of all interior surfaces of the car when the interior was gutted, and I paid special attention to the areas that carried air, both on the supply and return side before reassembly. For the areas I couldn't reach with a scrub brush, I borrowed an industrial strength Ozone generator and allowed it to run a few weeks in the interior of the car. Great airflow. No bad smells. 
Good luck!
