A/C runs cold, then turns hot (outside temp), but goes cold again when RPM is high

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girlfriendsls

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A/C starts off cold, eventually blows hot as outside temp, but turns cold again if I rev the engine to 3,000 rpm.

Sounds like a vacuum controller of some sort has a loose hose, but I read the air diverters are electric solenoids?

Any ideas from the experienced folks here?

Thanks!
 
From those symptoms, you are either low on refrigerant, or the evap temperature sensor is failing.
 
Replaced evap temp sensor, driver side. No change. (actually did both driver side sensors, did not do passenger)
Added refrigerant, no change.
It tends to work after I hear a valve making hissing noise. Just need to get the valve to hiss more often. LOL
The passenger is warmer than the driver.
Is that the DCC or the DCCV? I see both on eBay. Or something else?
Thanks!
Kelly
 
girlfriendsls said:
Replaced evap temp sensor, driver side. No change. (actually did both driver side sensors, did not do passenger)
Added refrigerant, no change...
Click to expand...

There is only one evaporator temperature sensor. There are two discharge air temp sensors (driver's side and passenger side), but those wouldn't cause your symptoms. There is also the ambient temperature sensor on the driver's side, but again that shouldn't cause your problem.

Did you check the high and low side pressures? What were they and what was the outside temperature? (And of course, you had the windows down and the blower on max speed and waited a few minutes for the readings to stabilize.) Surely you didn't add refrigerant without doing this...

I also assume that the compressor clutch is engaged the whole time.
 
I replaced one evaporator temperature sensor and one discharge air temp sensors while I had it all apart.

Did you check the high and low side pressures? - Nope, don't have the tools.
What were they and what was the outside temperature? - F-ing hot outside at the time, which is why I'm trying to fix it. :)
(And of course, you had the windows down and the blower on max speed and waited a few minutes for the readings to stabilize.)
Surely you didn't add refrigerant without doing this... - COME ON, OF COURSE I DID. It wouldn't be any fun if I didn't. Windows were down, max speed when I added a small can of refrigerant.

1loudLS is busting up right about now.
 
What do you mean you replaced one evaporator temperature sensor? There is only one.

You added a whole can of refrigerant without even knowing if it was low? I'm sorry, but I don't think I can help you. Still, I wish you good luck with it.
 
girlfriendsls said:
Did you check the high and low side pressures? - Nope, don't have the tools.
What were they and what was the outside temperature? - F-ing hot outside at the time, which is why I'm trying to fix it. :)
Click to expand...

well the you can rent the gauges for free at most auto parts stores, then once you have the gauge readings AND factor in the temp, then you can figure out what is wrong with the system. without at least that, itsd going to be pretty hard to fix it.


I hope you didn't cause any extra damage by over charging the system. or if it was actually low, you would have to have a leak, and if you have a leak, all the oil usually leaks out before the refrigerant does, so I hope that the system wasn't ran without oil destroying the compressor (and probably the entire system).

I wouldn't bust up mostly because you used the right terminology and called it refrigerant and didn't call it Freon... (thank you for that)


at this point, without the proper tools, your best bet is to take it to an AC shop and let them run a diagnostics on it and find out the problem.
 
March? So you went the entire summer without AC and are still trying to solve it in September?

Maybe I missed this, but what generation is this LS?
 
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