1993 Corolla automatic 4-door sedan A/C question

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  #1  
Old 07-10-06, 03:34 PM
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1993 Corolla automatic 4-door sedan A/C question

In 2004 I had a new A/C system installed, which worked for one day. In 2005 the same service department replaced the condensor, which was still under warranty, and the A/C worked so-so. This summer, the A/C was blowing mildly cool air. Because there is no more R-12, I had to have the car retrofitted for the new freon. Now it is coolish sometimes, not cool other times, never very cold. Is it possible to repair an A/C system, or does it mostly have to be replaced? The car runs well but has high mileage.

Thanks for any help!

silvermarple
 
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  #2  
Old 07-10-06, 03:37 PM
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You need to monitor the pressures of the a/c system. Then we can diagnose it. The only way to get your a/c colder than it was before r12 is to find a shop that has hot shot refidgerant
 
  #3  
Old 07-10-06, 04:41 PM
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1993 Corolla A/C issue

Do I understand correctly that there are two issues?

1. The pressure of the A/C system.
2. The type of refrigerant.

How do I monitor the pressure?
I can call service stations about the refrigerant.

I don't need the A/C to be colder than it was before it failed, just as cold as it was.

Thanks!

silvermarple
 
  #4  
Old 07-10-06, 04:57 PM
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type of refridgerant you really can't do anything about. unless you get a vacuum pump and a $25 cracker jack box epa sect 609 license.

You want the low side to be around 35-40psi and the high around 230-250psi

r134 won't get as cold as r12
 
  #5  
Old 07-10-06, 07:13 PM
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You said they replaced the ac system. Was this everything (compressor, evaperator, condenser, dryer, orfice tube, hoses/lines)
Then after it stopped working they replaced the condenser under warrenty. Why did they replace the condenser? was there a hole in it or something? I dont really see how a condenser could go bad in that short amount of time.

134a isnt as efficient as r12 so if you just retrofit, your ac will not be as cool, however you said they replaced the ac system.

I would recommend checking the pressure on both the low and high side.
 
  #6  
Old 07-10-06, 08:09 PM
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My fellow posters are correct, R-134a is not as efficient as R-12. However, the average consumer won't really notice a huge difference between the two under normal operating conditions. I wouldn't worry about that particular part. Besides, R-134a is cheaper than R-12. If you have to have further work performed on your AC system, it's going to be to your advantage.

Further information on your part would be helpful as zzzz1486 asked for. An A/C system consists of a condensor, compressor, evaporator, receiver/dryer, hoses/lines, pressure switches, relays, etc. Do you know what exactly they replaced? Is there any chance the system is still under warranty?

The way you described your problem, that it gradually got warmer over time, leads me to believe that you may be slowly losing your refrigerant (a leak somewhere). Chances are the people who serviced your system previously placed a UV dye in the A/C to help detect future leaks. That would be the first place I would start.

To answer your last question...an AC system can be repaired to a certain extent without replacing the whole system. Some types of repairs require the replacement of multiple parts of the system. For instance, a failed compressor requires that you replace not only the compressor, but the receiver/dryer and the expansion valve/orifice tube as well. This is because a failed compressor will often contaminate an A/C system...thus requiring the replacement of those other parts.

Take your car to a shop you trust and ask them to check the AC system for leaks. Make sure you tell them the history of the vehicle.
 
  #7  
Old 07-14-06, 03:47 AM
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1993 Corolla A/C question

Thanks, zzzz1486 and davzack. After reading your posts, I consulted with my spouse, and got some details.

The original replacement was a complete replacement; it cost about $1000. The part that failed and had to be replaced after about a day of operation was, he recalls, the compressor, not the condenser.

When the system wasn't working this year, we went back to the original repair shop. They told us that we would need a retrofit for R-134a, it would cost about $1000 again, and there would be no guarantee it would work any better.

We took the car to another shop, which retrofitted the system for about $250. My spouse thinks, therefore, that the whole system was not replaced.

Whether it's under warranty or not doesn't matter, because we have moved to another state.

The system blows plenty of air, and part of the time it's quite cool. But it's not reliably cool, especially when it's really hot. The guy we talked to at the original repair shop told us that he wouldn't try to fix the system if it were his car, because it worked pretty well. He said there was no leak.

I don't know if this information will be any help or not. My own inclination is to accept the system as it is, especially since I now know that R-134a is not as efficient as R-12. But it would certainly be great to be able to breathe when driving in the summer.

Thanks!

silvermarple
 
  #8  
Old 07-14-06, 08:14 PM
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It would probably benefit you to have someone hook up a set of manifold gauges to check the low/high side pressures. IF the pressures are within specifications then there's nothing else to do...except maybe get your windows tinted.

You also have to remember that the ambient temperature greatly affects an AC system's ability to provide cool air. You can see temperature differences as great as 10 to 15 degrees F depending on how hot/cool and humid/dry it is outside.

Getting your windows tinted can really help more than you think.

Oh, and a lot of people don't know about the MAX setting or recirculate aspect of their AC systems. When you have the AC set to MAX or the recirculate button pushed...air is drawn from inside the car and then passed over the evaporator. When you don't have it set to MAX or you have the fresh air button pushed, air is drawn from OUTSIDE the vehicle and then passed over the evaporator. Obviously it's much easier to cool air that has already been cooled before rather than pulling new hot humid air in from outside the vehicle. In other words, make sure you have AC set to MAX or the recirculate button pressed for optimal cooling.
 
  #9  
Old 07-14-06, 08:35 PM
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usually r134a on retrofitted vehicles does not cool as good as r-12 and is most noticable on hot days like above 90 degrees in slow driving or idling conditions.
if your really are not happy with it then you should probably see a shop that specializes in a/c work and repair they can probably make it perform better using r134a by adding a better condensor or possibly an extra cooling fan or insulating the liquid line so it has less heat loss before it gets to the passenger compartment or they may suggest a different refrigerant that would perform better in your vehicle.
 
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