Air conditioning mystery... please help!
07-03-2014, 01:52 PM
#1
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SL Member
Thread Starter
Join Date: Aug 2006
Location: Greenville, SC
Posts: 66
Air conditioning mystery... please help!
Let me preface this by saying that I've tried searching but to no avail.
My wife's 2006 Scion xB, with 140k miles, is having the following AC issue:
At idle, it blows cold air, on both fresh air (56.7F) and recirculate (44.7) modes.
After idling for close to ten minutes or so, the car starts to blow warm air, and the engine overheat light starts blinking.
Here's where it gets weird: I can turn off the engine, and immediately crank it back up, and I immediately again have ice cold air and no overheating warning light.
What could be the issue? Here's what I know:
R134a pressure when I first started the engine and turned on the AC was perfect according to my gauge.
R134a pressure when blowing warm air while overheat light blinking was low... but my HVAC buddy says that's normal since the system needed less pressure with the colder air.
Compressor was running like it should.
Fan was running the entire time.
Low pressure line was cold and had condensation on it.
All vents are blowing evenly (a common-ish problem with earlier xBs)
Engine seems to be slightly under load at idle with AC on. Normally idles smooth as silk at around 850rpm. With AC on, it gets a little rough, not bad, and drops to about 750-800.
Any insight is greatly appreciated. :thumbup:
My wife's 2006 Scion xB, with 140k miles, is having the following AC issue:
At idle, it blows cold air, on both fresh air (56.7F) and recirculate (44.7) modes.
After idling for close to ten minutes or so, the car starts to blow warm air, and the engine overheat light starts blinking.
Here's where it gets weird: I can turn off the engine, and immediately crank it back up, and I immediately again have ice cold air and no overheating warning light.
What could be the issue? Here's what I know:
R134a pressure when I first started the engine and turned on the AC was perfect according to my gauge.
R134a pressure when blowing warm air while overheat light blinking was low... but my HVAC buddy says that's normal since the system needed less pressure with the colder air.
Compressor was running like it should.
Fan was running the entire time.
Low pressure line was cold and had condensation on it.
All vents are blowing evenly (a common-ish problem with earlier xBs)
Engine seems to be slightly under load at idle with AC on. Normally idles smooth as silk at around 850rpm. With AC on, it gets a little rough, not bad, and drops to about 750-800.
Any insight is greatly appreciated. :thumbup:
01-16-2015, 10:03 AM
#5
Junior Member
Join Date: Jun 2012
Posts: 17
I believe AC is fine. It's a heating issue. AC is programmed to turn off when overheating and the red light turns on. That's from what I've noticed. I've been having that issue too during the summer. My AC blows cold at idle, but if I sit too long I'll notice the air isn't cold anymore and I'll immediately look at the dash and the red light will be on.
Red overheating light seems to come on at around 250 degrees F.
Red overheating light seems to come on at around 250 degrees F.
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