Tell me about automotive air conditioning...

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Wife's car is a 2002 Toyota Corolla that is mechanically sound. The AC system works but it takes a little time to start cooling off and it does not get 'cold' per se, but it does get cool. The system has never been touched, never opened, never recharged. It's as it was from the factory.

So assuming that there are no leaks, what makes an older AC system start to lose effectiveness over time? Does the refrigerant wear out? Does the compressor not, uh... compress as well? Dirty condenser? As much as I'd love to fix this with a miracle in a can, I'm pretty sure that's not really the best way of doing so.

We have a much newer car (a 2015 Accord) that gets real cold pretty much instantly so maybe our expectations are out of whack now.
 
R134a will slowly leak out through rubber components, and there's no stopping it. Have the system serviced.

Or you may need a compressor. They all wear out eventually.
 
Most of the time it's a refrigerant leak. It might be a leak that just started recently, or it might have been an extremely slow leak that took several years for the AC to lose effectiveness. It's acceptable to simply recharge if the leak is extremely slow. If it's a more major leak that started recently, the leak should be fixed before recharging.
 
Originally Posted By: rooflessVW
R134a will slowly leak out through rubber components, and there's no stopping it. Have the system serviced.

Or you may need a compressor. They all wear out eventually.


+1
 
Like said before it's probably low. I myself wouldn't use the cans. My truck went low one year and a shop topped it off and it worked well until it leaked again. I had a shop fix a leak at the low side port and it's been over a year it still blows cold. My compressor and condenser are original. I gather my compressor is weaker than what it was years ago as it takes a bit of time to cool down the truck. The condenser is atrocious. Do yourself a favor and clean the condenser. It will help prolong the life of the compressor. If it's a car you plan to keep for a while, I would have a shop change the drier too.
 
All systems leak. Some leak more than others. 15 years is a great run for an ac system. Most of the cars I see are about 5 yrs old and need a recharge.

Should add a splash of oil too.
 
Don't overlook condenser, if a lot of the fins are smashed from collisions with insects and such, the system will not work as well.

In my experience, compressors either work or they don't. Failure is usually catastrophic, not an "old and tired" type condition.
 
First thing to do is check the pressure?
If pressure is low, need to determine if there is any major leak or the compressor is weak.
Next, is there any funny noises when the compressor engange when you turn ON the AC?
Also, try to wash the cooling stack this usually include the radiator and condenser, they may be plugged up.
This is cheap, only takes a little time, some degreaser and water.

The good news is this AC is not that difficult to work on.
 
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+1 on looking the condenser over. I took my radiator out of my Corolla and back flushed the condenser and straightened out the fins as best I could. Made a noticeable difference in cooling. Lots of bugs, fur, leaves, pebbles lodged in there.
 
For a car this old also look at the air blend doors, see that they fully cycle from hot to cold,
they can stick, jam or break in one position and give the impression of bad a/c.

It's possible to have multiple problems, low charge and other issues.
 
My Accord behaved similarly last year. I added what I estimate to be around 6 oz of refrigerant (can felt half empty in the end; very scientific, I know). A/C performs much better now and the compressor cycles less.
 
You are low in refrigerant. When cars get old, you get leaks that, at least initially are often manageable like, adding a can in late spring and just doing that every year for a few years.
 
Originally Posted By: Bottom_Feeder
Wife's car is a 2002 Toyota Corolla that is mechanically sound. The AC system works but it takes a little time to start cooling off and it does not get 'cold' per se, but it does get cool. The system has never been touched, never opened, never recharged. It's as it was from the factory.

So assuming that there are no leaks, what makes an older AC system start to lose effectiveness over time? Does the refrigerant wear out? Does the compressor not, uh... compress as well? Dirty condenser? As much as I'd love to fix this with a miracle in a can, I'm pretty sure that's not really the best way of doing so.

.


ALL auto air conditioning systems slowly leak. They have a belt-driven compressor which means they have a rotating shaft seal... and that type of seal is NEVER perfect. It will probably be fine with a recharge.

Hybrid and electric cars now have sealed electric AC compressors, and those don't have the rotating shaft seal to leak, but they do still have rubber hoses and refrigerant does slowly diffuse through rubber.

Only home AC units, window units, refrigerators, etc. have truly hermetic plumbing (soldered connections and 100% hard lines, compressor fully contained in a metal pressure vessel) and are leak-proof until either the glass seal around the electrical conductors into the compressor fails, or a line corrodes.
 
I appreciate all the replies. Thanks!

So I guess after reading all this, assuming that everything else is in working order, and assuming that the refrigerant is just a bit low due to age and use, that one of those DIY recharge kits may actually be a solid idea as long as it's done correctly? I'm certainly willing to try that as long as it doesn't cause issues. We're probably only going to be keeping the car for another year or so but the temperatures we're seeing this summer is killing us.
frown.gif
 
Originally Posted By: exranger06
or it might have been an extremely slow leak that took several years for the AC to lose effectiveness.


100% true!


R-134a is a VERY TINY molecule.... so small, that is finds it's way through the pores in hoses on older systems easily.

Also, consider the shaft seal on the compressor... for these to be 100% leak free over 15 is almost an act of God.
 
Originally Posted By: Bottom_Feeder
one of those DIY recharge kits... long as it's done correctly?


It's impossible to combine these two pharses in one sentence.

A D-I-Y recharge kit (especially if it contains "stop leak") is never ever ever ever ever a good idea.

Just use pure R-134a only.
 
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