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Car AC troubles

Started by Qweaver, May 06, 2014, 08:02:35 PM

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Qweaver

My daughter's 4 year old car is blowing hot air.  I tried to add 134a today with a new pretty good quality gauge and manifold set and I could not get it to take Freon. Suction was 40, tank pressure about 70 and high pressure a little over 100 and up t0 150.  I have no clue what was happening here.  The pump clutch was working and with that delta it should have been sucking Freon.  I've worked on many home and car AC units and never had this happen.   It never made any cold air even when the high pressure was 150.  ?
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

yukon cornelius

a lot of new cars have a door that opens and closes stopping the flow of air through the heater core and forcing it through the evaporator.  the door has a motor and they fail or the door fails. most likely cause given your description. ok does the ac clutch cycle on and off? if it stays on its not low on freon. at those pressures I don't believe its low. another check is to feel the accumulator usually at the firewall. an old saying is beer can cold, good to go. if the accumulator is cold and sweaty as a can of beer just pulled from a cooler its not low. hope this helps
It seems I am a coarse thread bolt in a world of fine threaded nuts!

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pineywoods

Agree with Yukon, most likely an air duct control problem. Most vehicles use a vacuum pot to activate the doors in the ductwork. A broken or missing vacuum hose could do just what you see.
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yukon cornelius

I just remembered the name of the duct door. its called a blend door. a have had a few that ive had to fix. some are vacuum controlled but some have a small motor. some have a cable. you might try a google search on that model car "ac not working"
It seems I am a coarse thread bolt in a world of fine threaded nuts!

Making a living with a manual mill can be done!

ScottAR

Most of the late models I'm seeing these days  have electric motors on the blend doors.  Blend door actuator.  Some models have 3-4 of the little buggers and most are not cheap.  Also, don't remove them from the blend door they run and cycle them off the heater box.   Messes up the guts and they don't work right after that.    Same goes for the new replacement...  put it on and then cycle it. 
Scott
"There is much that I need to do, even more that I want to do, and even less that I can do."
[Magicman]

clearcut

I had a similar problem, and the solution came out of left field. It's simple but worth a look. The nut that held the temperature control assembly to the dash had worked its way loose, though it was not obviously loose. The electronics were shorting and not allowing the blend door to operate correctly.

I simply pulled off the temperature control knob, tightened the nut and solved the problem.
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albirk

Check to see if it has a (cabin filter) my 01 chevy had one and the 03 did not

Qweaver

Thanks all.  I will try to check out the blend door operation today.  I still wonder why the pressures would not come up when I tried to add Freon.  The high pressure was around 110 and came up to 150 a few times.   It appeared that no Freon was being put in from the tank.   But we should have got some cool air at those pressures which really makes the blend door theory probable. 
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

Qweaver

Took the car to a local repair shop today.  He could not get the pressures to come up either.  Said the pump was bad.  $600 + to replace.  How did I get the high side up to 150 psi if the pump is bad.  But I did not make cold air that was getting to the car at those pressures.
So Many Toys...So Little Time  WM LT28 , 15 trailers, Case 450 Dozer, John Deere 110 TLB, Peterson WPF 10",  AIM Grapple, Kubota 2501 :D

yukon cornelius

!!!!SECOND OPINION!!! first off your pressures are not far off at all. I never check high side due to large amounts of refrigerant loss. I don't believe one bit the compressor is bad. feel the low side line at the accumulator. is it cold?
It seems I am a coarse thread bolt in a world of fine threaded nuts!

Making a living with a manual mill can be done!

jargo432

You won't believe this, and I'm sure it's not the problem but...

Years ago I had a car that had a bad sensor in the suspension that caused the A C not to work.  The way it was explained to me was the car was designed to shut the AC off in the event of extreme shifts in the car.  The manufacture was afraid if the AC compressor kicked on during an emergency it would cause a power change in the engine and thus a loss of control.

Got the sensor changed and it fixed the problem.

CRAZY
Jack of all trades.

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