A/C Pros - Replace expansion valve with compressor?


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Old 10-28-12, 05:32 PM
J
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A/C Pros - Replace expansion valve with compressor?

My wife was complaining that the A/C in her '04 Camry 4-cyl stopped working suddenly. It has had a small leak for years but for good measure, I stuck my gauges on it before heading to the parts store to pick up a can of R-134a.

To my dismay, the high and low sides both read 50 psi with the engine on and compressor clutch turning. Sounds like a bad compressor... fantastic...

I know it is good practice to always replace the filter/dryer and expansion valve with any compressor replacement. I did a little digging and it looks like Toyota was kind enough to put the expansion valve on the evap coil, buried behind the dashboard. Book says about 7 hrs labor for that job. I've replaced evap coils in other vehicles before and it isn't fun.

If anyone has experience with this particular make/model/year, think I can get away with just replacing the compressor, filter/dryer and condenser coil - leaving the evap coil and expansion valve alone?

If it matters, the compressor sounds "normal" when it runs. No weird sounds that would indicate that it has failed.

Thanks!

- Joe
 
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Old 10-28-12, 09:41 PM
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these are known to have bad expansion valves but i don't see where 7 hours is needed are you sure you looked it up right?? but a low charge alone could cause this. with a/c systems temp is normally = to pressure. if it don't start at room temp meaning its lower than air temp then the system is low.giving a 10deg diff. having the same pressure on both sides can mean one of two things. A the charge is to low for the valve to work correctly or B the valve is stuck open but even then the pressure should still be = to air temp or within 10 deg.
 
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Old 10-29-12, 05:58 AM
J
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You're right - it was 7 hrs for the whole job. 5 hrs for the expansion valve.

I wouldn't be surprised if the system is low - it has a slow leak and I haven't charged it in a while. Every automotive A/C system I've worked on had a low pressure cut-off switch that would open the compressor clutch circuit if the pressure dropped too low. The compressor clutch wasn't cycling - it was on solid and the high and low sides didn't change from 50 psi. I did this test yesterday morning - probably 75 deg or so.

Still think this might not be the compressor?

Thanks!

- Joe
 
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Old 10-29-12, 08:29 PM
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50 is low even when a/c is off. the pressure switch you talk about should activate around 25-30 psi and with yours at 50. i would still start with the expansion valve. if its stuck open there is no way for the compressor to change pressure.
 
 

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