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A/C: Compressor engages, but no cold air

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Old 07-30-2009, 10:23 AM   #1
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A/C: Compressor engages, but no cold air

as the title says, my A/C compressor engages when I turn on the A/C, but there is no cold air. A buddy of mine and I refilled the system with a R134a refil kit thinggy from walmart and still nothing....it blows air, so it's not the blower, but it blows outside temp air.

Ideas on what to look at next?
Old 07-31-2009, 10:44 AM   #2
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Re: A/C: Compressor engages, but no cold air

Check the airbox door, my van I had it adjusted to provide most heat as alot of the foam had disappeared, when I refilled the AC it blew slightly cool air.

Does the compressor cycle on/ off?

You said you refilled it, was it empty? Did you pull a vacume on the system before refilling?
Old 08-09-2009, 12:27 PM   #3
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Re: A/C: Compressor engages, but no cold air

I do not like the "new"-er R134a..

But I think it is about the only game in town. And it is probably OE stuff.

The system CANNOT have any air in it, and that is why les asked if you vacuumed it.

You said that the compressor ran OK. That says that it is not low enough in pressure/fill to have the low pressure switch be holding out the compressor from running. But it may be that it doesn't have ENOUGH R134a in it to blow cool air.

I am having issues right now with the AC in my Motorcoach. But my problem is that I can't get the AC compressor clutch to run. My system is either low (and the low pressure switch is holding the clutch out or the $20 switch itself is bad), or it is something else, more expensive.

I have decided to let a Shop look at it.
Old 08-09-2009, 02:54 PM   #4
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Re: A/C: Compressor engages, but no cold air

Quote: Originally Posted by Steady Eddie
I do not like the "new"-er R134a..

But I think it is about the only game in town. And it is probably OE stuff.

The system CANNOT have any air in it, and that is why les asked if you vacuumed it.

You said that the compressor ran OK. That says that it is not low enough in pressure/fill to have the low pressure switch be holding out the compressor from running. But it may be that it doesn't have ENOUGH R134a in it to blow cool air.

I am having issues right now with the AC in my Motorcoach. But my problem is that I can't get the AC compressor clutch to run. My system is either low (and the low pressure switch is holding the clutch out or the $20 switch itself is bad), or it is something else, more expensive.

I have decided to let a Shop look at it.
I got to thinking Eddie, wonder if the Engine vacume would be enough to suck one down, might try to make an adapter next time instead of my ancient sealed compressor setup. Wonder if the compressor oil is bad for O2 sensors?
Old 08-09-2009, 04:37 PM   #5
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Re: A/C: Compressor engages, but no cold air

OK guys , this was told to me by a dealer mechanic

you can chalk this up to an urban legend , pure BS , or take heed

DO NOT burn r-12 freon in any way , the end result is similar to mustard gas !

Nope , I dont know if its true or not , but i always heeded the warning , a vac seems awful cheap compared to death , lol
Old 08-09-2009, 06:13 PM   #6
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Re: A/C: Compressor engages, but no cold air

I would say check to see if the compressor is kicking on if it isnt check the cycling switch

u do need to REPLACE the accumulator when u convert from a R12 to R134a system and pull all the hoses off and clean them with a cleaner including the evap and condensor so u can look up the PROPPER amount of oil in each even the compressor and replace the factory oil with PAG or MINERAL oil when u chean the hoses i would put in a orific tube (1-3bucks) then put the retro fit fittings on and pull a vaccum for a min of 15min 45 max the longer the colder it will be up till 45 min then it doesnt seem to matter after that. then u can charge the system to the right amount with i think is like 1lb9oz but it should be under hood on the A/C sticker

sry dont mean to step on any toes but ive done this at the dealership alot here lately since no one wanted to sell there old cars untill the govt clunker thing
Old 08-09-2009, 07:31 PM   #7
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Re: A/C: Compressor engages, but no cold air

No prob man, always open to an honest opinion or fact.... I have done several conversions, and being lazy I only sucked them down and refilled, didnt clean anything up, didnt change accumulator oil or orrifice tube. Altho I probably should have everything has always worked fine.... Maybe just lucky....
Old 08-09-2009, 09:22 PM   #8
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Re: A/C: Compressor engages, but no cold air

Hey--

This has turned into a swell thread, I think..

I wanted to point out one other thing..

If you have a R234a system that is slam empty, then you have to put, like a 1/4 full charge into it, to get the clutch to pull in and over ride the low pressure switch. Then, you may have one bad leak someplace, and pssttt..all the R134a you just put in it, goes away. It is one of the reasons to take it to a Shop, as they have UV dye, that shows the leak under a black light.

"They" say to jumper out the low pressure switch to see if the compressor clutch will pull in, if it isn't, when you turn on the AC. I would be scared to do this, however.

May be the jumper would be OK for a quick test, but the R134a is a lubricant. I'd be worried about the compressor bearings.

I was not aware of the older R12 turning into a poison gas when burned...?? Guess that vetoes the idea of using engine vacuum..

Last edited by Steady Eddie; 08-09-2009 at 09:32 PM.
Old 08-10-2009, 02:30 AM   #9
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Re: A/C: Compressor engages, but no cold air

as said above remove the Cycling switch (lowside) pressure switch on the accumulator and jumper it just one pin to the other (make shure a/c is cut on in car) but if that works u can put a set of gauges on it and u can use the yellow 3rd hose with a can tap to charge the system and i know autozoo sells r134a with UV dye for like 9 buck a can (12oz) ull need allittle over 2 cans
Old 08-10-2009, 07:36 PM   #10
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Re: A/C: Compressor engages, but no cold air

Quote: Originally Posted by brios
as said above remove the Cycling switch (lowside) pressure switch on the accumulator and jumper it just one pin to the other (make shure a/c is cut on in car) but if that works u can put a set of gauges on it and u can use the yellow 3rd hose with a can tap to charge the system and i know autozoo sells r134a with UV dye for like 9 buck a can (12oz) ull need allittle over 2 cans
Yeah, what he said...
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