recharged AC on Yukon still no cold air

ezbtr

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With new rechharge kit, pressure is in. Green zone, when AC on. Compressor clutch engages but no cold air?? Ideas?
 

alldodge

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With new rechharge kit, pressure is in. Green zone, when AC on. Compressor clutch engages but no cold air?? Ideas?

Could be a few things, but mostly depends on what pressure your reading and what was the current outside temp. To do it correctly you need a digital temp gauge so you can read what the temp is at the truck. Note in the pressure chart in the link below, the pressure should change based on outside temp. If you get where the low side is correct but don't have a high side gauge you could have a orifice, or expansion valve restriction. This being said need also to make sure your damper door is opening allowing air to pass through the A/C coil. Your low side (suction) line should be cool to the touch and have water bead up on it.

http://acprocold.com/faq/r-134a-system-pressure-chart/
 

MTboatguy

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How much 134 did you put in it? I just did one of my older Ford Trucks and it didn't get cold, didn't get cold and didn't get cold, even though the gauge showed it had the right amount in it, come to find out, it did not, It ended up taking 36 ozs of 134a to get it cold again.

By the way, found out, that Home Depot has the least expensive price on 12 oz cans of 134a, I paid $7.97 a can for it the other day, after I paid $12.99 at both Autozone and O'Reilys auto.
 
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ezbtr

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90 degrees outside, guage shows 50 PSI and 375 Kpa at end of green zone on guage seems like maybe 1/2 of the 20 oz. can, didnt want to overcharge past green zone, also AC comp/clutch goes on and off every few secs when AC turned on
 
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alldodge

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90 degrees outside, guage shows 50 PSI and 375 Kpa at end of green zone on guage seems like maybe 1/2 of the can, didnt want to overcharge past green zone

Sounds within range provided the high side is not going past it's limits. For a simple adding of Freon is fine with a single gauge, but problems such as yours you need a high side gauge reading to find out.

By the way, found out, that Home Depot has the least expensive price on 12 oz cans of 134a, I paid $7.97 a can for it the other day, after I paid $12.99 at both Autozone and O'Reilys auto.

Found 30 pound tank for 79.99 at TSC, after shipping came to 10210
Comes to 2.55 a 12oz can
 

bruceb58

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Ad Dodge stated earlier, just because the air isn't coming out cold does not mean it needs more refrigerant. You could have a bad expansion valve and that could be the cause.

Has the system ever been open to the air? Was the system operating properly and it just started getting warmer over time?

Was the compressor not coming on until you started putting in the 134?
 
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no704

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Also change (read remove) the cabin air filter under the passenger side dash.
 

midcarolina

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90 degrees outside, guage shows 50 PSI and 375 Kpa at end of green zone on guage seems like maybe 1/2 of the 20 oz. can, didnt want to overcharge past green zone, also AC comp/clutch goes on and off every few secs when AC turned on

It's either still low on freon and is cycling on low pressure or is cycling on high pressure.........
When the compressor is cycling is the gauge moving a considerable amount? if not try different gauge.... those kit gauges are super cheaply made
does the electric fan in front of the condenser ever come on?

If you have a harbor freight nearby they sell a manifold set that comes with the low and high side adapters.....they will work just fine for DIY and think they are around 50 bucks
 

ezbtr

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Retested just now and when AC is on, compressor kicks in for a few seconds, pressure drops on gauge idle rises, when trigger depressed, then when trigger released pressure back up to max in green zone, idles down, return line NOT cold
 

MTboatguy

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Sounds like you are still low on 134a in the system, you might drop by a shop, I know most of the shops around my area will check them out and don't charge to do it.
 

midcarolina

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The low pressure switch cuts out around 25 psig.........and cuts back in around 50-55 psig, your gauge should confirm this, if not like I said earlier get a different gauge.........two things will cause the low pressure, low on freon or screen at orfice clogged.
That system should hold a little over 2 lb of freon you can look at the tag under the hood to verify.
 

alldodge

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Retested just now and when AC is on, compressor kicks in for a few seconds, pressure drops on gauge idle rises, when trigger depressed, then when trigger released pressure back up to max in green zone, idles down, return line NOT cold

If you compressor is only turning on for a few seconds you don't have enough Freon. What puzzles me is the rest of your post; when you pull the trigger the reading goes down. I assume when you pull the trigger on the hose the Freon starts going in, the issue is the gauge should be going higher not lower. Pressure in the can is higher then 55 except when it's empty.

can I hurt anything by "over charging"?

Yes, if pressure gets to high the compressor and other components can be damaged
 

jimr

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what year Yukon is it ? Our Tahoes are horrible about the blend doors having to get recalibrated all the time.
 

Ol' Man

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The DIY freon set ups sold at parts stores should be outlawed before some gets hurt or just causes more harm than good. Sounds like the expansion valve and or blend doors as mentioned above. Just because the AC doesn't blow cold doesn't mean you need to add freon. Find a competent repair shop.
 

MTboatguy

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If you pick up a set of gauges at Harbor Freight, like I did,and read a bit, it is not hard to repair a air conditioner in a vehicle. it is a heck of a lot easier these days, than it was in the days of R12 refrigerant, that stuff could kill ya!
 

Fishing Dude too

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How many ounces of Freon is to be in the system? You need to go to a repair shop, these add Freon kits ruin more systems than they help.
 
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