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Any Air-Conditioner Improvement Mods?

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79K views 67 replies 42 participants last post by  sherlock9c1  
#1 ·
Are there any Air Conditioner Improvement Mods?

Just got my AC competely charged.
Works OK except in the Hot Sun.
Then takes a while to cool down.
and
Not very well at Idle.

My Dad's 94 Roadmaster seems to be cooler and quicker.

Was wondering if there were any tricks to improve AC performance?
 
#2 · (Edited)
Not really sure any mods are required as much as just making sure it is working as well as possible. There isn't really much you can do to the fundamental design of the system (evaporator and condenser areas are fixed).

I just went through mine recently and it is working as well as I remember my brand new Impala SS systems working. Cleaned the orifice screen, wiped down all of the seals with new oil, added new oil to the system, baked the accumulator/drier in the oven at 175ºF for about 8 hours, quickly threw it on the car, pulled the system down to -30" for a few mins, threw a quick charge without running the system and pulled it down to -30" again then charged it back up until the pressures were correct...with both fans running. Ice cold at idle in the current south Florida heat and the evaporator drain looks like a freaking faucet cwm4

All I can offer is:
  • make sure both fans run when it is warmed up and the A/C is on
  • make sure the condenser is clean
  • make sure the orifice is clean
  • insulate the cold line since the orifice is way up at the battery and the cold refrigerant has to go all the way back to the firewall past the hot engine
  • check the low/high pressure relationship carefully since this is where cold comes from
It's a lot more work, but if you are still unimpressed after all that, you may want to check that all of the mixer flaps are working correctly and the evaporator is as clean as possible.

EDIT: one last thing I forgot to mention was the fan thing. It turns out that replacement fans (the heater fan inside the I/P) have smaller squirrel cages with fewer blades. If you have ever replaced it, you might want to see if you have the newer (not) improved design that is moving less air than the original. There are pictures comparing the two floating around somewhere.
 
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#3 ·
Dan Fahey said:
My Dad's 94 Roadmaster seems to be cooler and quicker.
Click to expand...
That shows that the basic system is a good one. It is the same on both cars. Scott's tips are good ones.

Is your dad's car a lighter color? Does it have the Sungate windshield and yours does not?

I was suprised at how much better my system worked when I evacuated it and put in exactly how much refrigerant it called for. I had previously used the pressure chart from the FSM and it was ok, but it worked a lot better with EXACTLY the amount called for.

You may consider this;
http://www.aircondition.com/vov/

but you would be adding a moving part that could fail, vs the bulletproof orifice tube. I bought one, but never installed it. Lost it in the moves.
 
#4 · (Edited)
VaderSS said:
That shows that the basic system is a good one. It is the same on both cars. Scott's tips are good ones.

Is your dad's car a lighter color? Does it have the Sungate windshield and yours does not?

I was suprised at how much better my system worked when I evacuated it and put in exactly how much refrigerant it called for. I had previously used the pressure chart from the FSM and it was ok, but it worked a lot better with EXACTLY the amount called for.

You may consider this;
http://www.aircondition.com/vov/

but you would be adding a moving part that could fail, vs the bulletproof orifice tube. I bought one, but never installed it. Lost it in the moves.
Click to expand...

I went to my buddies gas station and used his AC machine to blead the system all the way down.
Put in new oil and freon.
Works well but in hot sunny weather think it should be colder quicker.

May replace the Fan Motor and Fan Blade. The Motor is buzzing at high speed.

But is there a intake screen on these cars?

D
 
S
#5 ·
No intake screen.

The VOV was discussed in this thread.

Use one of those reflective foldable windshield covers - it helps bigtime.

Do you have a crank underdrive pulley on your car? Are the idle speeds different?
 
#13 ·
As others have mentioned, you need a set of gauges, and a vacuum pump.

Here's an image, link and pricing for the gauges from Harborfreight:

Image

$49.99 http://www.harborfreight.com/catalogsearch/result/?category=&q=134+gauges

And also a vacuum pump. The first shown is a one that you use with an air line from your shop compressor, and the second is an electric.
Image

$12.99, http://www.harborfreight.com/catalogsearch/result/?category=&q=vacuum+pump+134

Image

$79.99, http://www.harborfreight.com/25-cfm-vacuum-pump-98076.html

I would suggest checking the orifice tube for debris. It's located in the lower tube of the condensor at the threaded line connections near the battery. This would clue you in to knowing if there is any debris in the system.

Image


$1.27, http://www.ackits.com/merchant.mvc?...en=PROD&Store_Code=01&Product_Code=31-50006&Category_Code=Chevrolet96caprice5-7

If this looks like it has any particles/debris on it, especially in the screen area, I'd suggest flushing the system (Condensor, evaporator core, and lines). This is the proper way to flush the heat exchangers:

The Evaporator's inlet is at the bottom and therefore only one flush in the back flush direction (top to bottom).

The condenser's inlet is at the top and as with all heat exchanger flushing, this must be back flushed first (bottom to top).

I used the cheap flush stuff available from Advanced, and although it worked, I was happier using a fluid gun and acetone. The stuff from Advanced didn't evaporate fast, much at all after I flushed with it, and used compressed air to follow it up. Acetone will flush the system of contaminents (and water!), and evaporate quickly.

The next thing to do is replace the O-rings and sealing washers @ the compressor. O-rings can be bought from Ackits.com as well, and here's an image, pricing, and a link:

Image


$10.51, http://www.ackits.com/merchant.mvc?...reen=PROD&Store_Code=01&Product_Code=CP3016&Category_Code=Chevrolet96caprice5-7

The last thing is the sealing washers at the back of the compressor. I believe you'll need a 17MM socket to get that flange nut off. These are ~$10 at the stealership

Image

Image


I like the typical electric operated vacuump pump, as opposed to the super cheapie myself. I like to draw a vacuum on the system for at least an hour. Using the gauges & pump you should be able to pull 30" of vacuum without a problem. Then, I pull the plug on the vacuum pump, and leave it connected for another hour to ensure the system is holding a vacuum.

Then charge the system thru the gauges (R-134 gets connected to the center {yellow} hose, and thru the low pressure (blue) hose.

The last thing I'd highly suggest on replacing would be the accumulator (receiver/dryer). They're cheap, and it'll ensure you don't have moisture in the system

Image


$15.60, http://www.ackits.com/merchant.mvc?...en=PROD&Store_Code=01&Product_Code=37-23289&Category_Code=Chevrolet96caprice5-7

Good luck.
 
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#11 ·
You can get the manifold gauges and a vacuum pump for AC systems at Harbor freight for less than $80 out the door(maybe a little more if you have it shipped). I had a friend who bought their gauges and vacuum pump and used it successfully on his Ford F150 truck. Harbor Freight may be inexpensive but they do sell some good stuff. - Peter
 
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#14 ·
I have used the vacuum pump that runs off compressed air, for years, with good results. However, now that electric pumps can be had for $80, I prefer them. I don't like running my compressor, for 30-45 minutes, to evacuate an AC system.

I also have Am American made R12 manifold set, which, of course, is better than my HF R134 manifold set (both get the job done).

TIP..just before you introduce the refrigerant into the vehicle, "purge" the manifold hose of air, by slightly lostening the fitting, at the vehicles service ports, to let a little R12/R143 push the air out.

READ UNDERSTAND ALL SAFETY RULES RE REFRIGERANT IF IT HITS YOUR EYE IN LIQUID FORM, YOU CAN GO BLIND. Also, if it contacts glowing hot metal, it can turn into a toxic gas.

If in dought, pay a pro.
 
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#15 ·
Lots of good info in this thread.

I bought those HF gauges and they leaked every where. Tightened up all the fittings on the manifold block and still leaked every where.
So back they went.



Any one else think this thread is Sticky worthy?
 
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#16 ·
GreenHornet said:
Lots of good info in this thread.

I bought those HF gauges and they leaked every where. Tightened up all the fittings on the manifold block and still leaked every where.
So back they went.



Any one else think this thread is Sticky worthy?
Click to expand...

MY HF gauges work good. I've used them on 5-6 cars
 
#19 ·
I wish there was a compressor upgrade or something.

Nothing sucks worst than sitting in traffic andlooking at people with their hair blowing in the wind like some damn Beyonce video while I'm still boiling in mines. :-(
 
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#21 ·
I changed my compressor and serviced the A/C the proper way as was stated earlier in the thread. The A/C blows icy now.

Something else to consider though is that I pulled the headliner out of my wagon a few days ago. The heat radiating off the roof is friggin brutal! Keep in mind that I'm 5' 2" and my head is nowhere near the roof, LOL. Before I put the headliner back in, I'm definitely installing some type of heat barrier. This HAS to provide some type of improvement/assistance for the HVAC system.
 
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#22 ·
When I did my interior, I applied "FrostKing" self adhesive foam backed aluminium "duct insulation" to the underside of the roof panel.

It made a big differance. Before, you could have fryed an egg on the metal (were it not for gravity). After it was warm, not HOT to the touch.
 
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#23 · (Edited)
bolt-on

Nobody mentioned the caddy rear airducts..

They will cool the rear 2 time faster, and will provide better flow to the interior venting.

Pick up from any caddy 94+, need the bottom dash vent from caddy too.

If the roadmaster had the electronic climate control, it's able to redirect air at many more place at the same time.
 
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#24 ·
SSnow said:
Nobody mentioned the caddy rear airducts..

They will cool the rear 2 time faster, and will provide better flow to the interior venting.

Pick up from any caddy 94+, need the bottom dash vent from caddy too.

If the roadmaster had the electronic climate control, it's able to redirect air at many more place at the same time.
Click to expand...
Actually, you can go back to '93. I just got a set from a '93, and installed them in our B4U. Nice addition, especially with the little one in the back seat.
 
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#27 ·
Everything CRASHED

Just as I was gathering everyones advice.
Then AC stopped working.
It almost disentigrated..
The Balancer ripped out and caused a huge vibration.

Limped to King Pontiac got all new parts
Then dropped off to a mechanic.

Spent $566 to get a whole new GM System.
Went to King Pontiac and got new parts.
Plus a new Tensioner and Belt
$430 plus $126 labor.

I have cold air now..
 
#28 ·
Good for you Mr. Big Wallet!

I got mines fices today and it cost me 103$ so NOW! LoL!

I would have felt better about it if my starter had not decided to go out on me just before I left the shop tho! (dammit)

Cost me 180$ So much for that good ole feeling.
 
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#29 ·
COFFEE said:
Good for you Mr. Big Wallet!

I got mines fices today and it cost me 103$ so NOW! LoL!

I would have felt better about it if my starter had not decided to go out on me just before I left the shop tho! (dammit)

Cost me 180$ So much for that good ole feeling.
Click to expand...
$108 that is great...

I wanted all new parts and Not a reconditioned AC.
The tensioner and new belt were part of the PM upgrade.
It wa a fair price and at the right time too.
Hot miserable days and do not have to use HIGH all the time.
Once cooled down can drop the Motor speed to a more quite postion.
 
S
#30 ·
Many of these cars will slowly leak refrigerant over time given their age. If the AC doesn't blow real cold, you could try putting a can in. 1.75 lbs is the total system capacity so don't overdo it. If yours has completely leaked out, go ahead and replace the orifice tube and O-rings, then vacuum it down and refill it (or have a shop do it).

The other thing is to prevent the sun from heating the interior by having your windows tinted and using a shiny aluminum sunshade on the windshield when the car is parked. These two mods will make a HUGE difference.
 
#32 ·
+1 on the HF gauges. Best $30 I ever spent at HF.

Get the electric vac pump, even with the pneumatic one with a huge compressor cannot pull as deep a vacuum as the electric ones.

Past couple cars I've totally flushed the system, replaced drier and o-tube and charged to factory specs. AC works better in them then any other car I've had.
 
S
#38 ·
Pusher fans on the front of the radiator setup instead of on the rear would push more air at low speeds. Caddy Cateras and Ford Tauruses have some nice fans from what I've heard.
 
#41 ·
Being that it is still summer here I have a tip

Take apart the AC box and CLEAN the evaporator coils. All sorts of junk gets caught in them and reduces air flow. You can pick out any loose stuff by hand, Maybe use a vacuum depending on how small it is. Low pressure water rinses out the junk good and it will drain out the AC drain as long as it is not plugged. I'm not saying its plugged on every car but its something to look at.
 
#43 ·
Yes! They also make cleaner that sprays through the drip hose. I used it on some cars in the past. It is supposed to foam up and clean all the junk out of the evap.. But I dont think it would do much for hair/ leaves... I'm pretty sure once the blower motor and or lower pan is out, You will have some access to clean it w/o taking the WHOLE ac box out.
 
G
#45 ·
This thread has been a life saver! Thank you all for your valuable input! I finished my putting my AC system together today. I've never done any kind of AC work short of buying a can with the hose and filling the system. I replaced the compressor(it seized), accumulator, orifice, and o-rings. I also flushed the whole system and vacuumed it with a vacuum pump and manifold gauges from HF as per recommended in this thread. I'm glad I went the route of buying my own AC tools since now I can do this on any car and save hundreds by not taking it to a shop to do something that was so easy to do. Took the car out for a drive and the AC vent temp dropped to 36 degrees!! I'm good with that!
 
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#46 ·
Image

evap I wasn't planning on pulling this out but, I'm glad I did it was nasty
Image

canister, accumulator or whatever you want to call it
Image


compressor

Image

accumulator polished:D:D

AC lines polished


these are the infamous AC line that right on top on the control arm. They were quiet dirty but, looked fine until I did the water test. Two pin size holes the naked eye couldn't see. So went to Advance put and order in and they will be here tomorrow.
Image
 
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#47 ·
Nice!

I saw this picture:

Image


and thought, he's not going to try to polish that compressor is he? Then I saw the next picture. :D Looks great!
 
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