Strange A/C problem...any help?

[HayaBuddha]

I've searched around and found no answer to this, so if anyone knows A/C stuff, please help out with some ideas.

I have had multiple cars before that sprouted leaks, ran low on freon or started having compressor issues, all of which had symptoms of the A/C kicking in and then later blowing outside air with no cooling. Our 2002 KJ Limited is having the opposite problem.

When you start the car, the A/C only blows outside air and it feels really humid. If you drive it awhile or leave it idling in the driveway, after maybe 10 minutes it will start to blow the normal good cold A/C air and continue until you stop the car. If you are driving and it has reached that point of working correctly but you stop somewhere, go in for one second and come right back out, when you restart the car, you are back to the humid, non-cooled air.

Any ideas? Thanks in advance!

 

[Porkchop]

Have you check the charge if you have 134a it is not the same as your older cars that may have had r12 and 134a will need to be charge to keep it at its peak over time.

 

[osufans]

my jeep did that...turned out to be a leak in the condensor. it would slowly lose pressure and not get as cold. mine was just a pinhole leak, so i repaired it with some JB weld two-part epoxy (the stuff in the tubes, not the putty looking stuff).

 

[bugnout]

I know this sounds strange, but do all of your fan speeds work? I thought my A/C was going out, until I changed out the fan resistor.

 

[HayaBuddha]

Thanks for the input folks...

I know this sounds strange, but do all of your fan speeds work? I thought my A/C was going out, until I changed out the fan resistor.

Do you mean the in-cabin fan control as in 1,2,3,4? If so, they all work, yes.

my jeep did that...turned out to be a leak in the condensor. it would slowly lose pressure and not get as cold. mine was just a pinhole leak, so i repaired it with some JB weld two-part epoxy (the stuff in the tubes, not the putty looking stuff).

Yours started off hot then went cold? How did you locate the leak?

Have you check the charge if you have 134a it is not the same as your older cars that may have had r12 and 134a will need to be charge to keep it at its peak over time.

No, I haven't had the charge checked...didn't think it would be that if it started not cold and then got cold without a problem after 5-10 minutes and stayed cold. Once it finally goes cold, it doesn't get "un-cold" until I turn the engine off again.

 

[LibertyTC]

Generally when AC/condenser is not working right the AC shops will re-charge and install a dye or tracer to locate the exact location of a leak. Many times it is a leak in seals of compressor or the condenser.
Best to have it professionally diagnosed. Best-O-Luck.

 

[JeepJeepster]

Do you mean the in-cabin fan control as in 1,2,3,4? If so, they all work, yes.

No, he means the engine cooling fan. The A/C will work while the Jeep is in motion but will not work while the jeep is stopped. Thus why your A/C doesnt work when you first start the Jeep.

 

[greg_kj]

In my case it was a faulty low-pressure sensor, also as an increased air gap in the worn compressor clutch. This two problems appeared at the same time resulted in totally inpredictable a/c behaviour

The great guide to a/c compressor clutches is at Sparky's: http://www.sparkys-answers.com/2009/03/2002-jeep-liberty-intermitent-ac.html

 

[HayaBuddha]

No, he means the engine cooling fan. The A/C will work while the Jeep is in motion but will not work while the jeep is stopped. Thus why your A/C doesnt work when you first start the Jeep.

That's what is weird. Whether the Jeep is idling in the driveway or driving for the 5-10 minutes of warm air, it turns cold after that time frame...it doesn't rely on the driving part.

I've replaced the fan with a better one and replaced the fan relay, as that is a commonly bad item on these things, but neither affected this change as they were some time ago.

 

[osufans]

Thanks for the input folks...

Yours started off hot then went cold? How did you locate the leak?

Hmm, well, it wasn't hot, but wasn't very cold either. After driving for a while (5-10 mins) it would start to cool better, but when I would be in stop and go traffic, the air wasn't very cold at all. It really only cooled efficiently at highway speeds with continuous driving.

I located the leak because the front condenser appeared oily on one side. I got a spray bottle with some soapy water in it, and spritzed it up and down the side that was oily. It started bubbling over the leak, and that's where I patched it up with some JB Weld. Been fine for over three months now.

 

[HayaBuddha]

Okay, got a chance to drive the Jeep today (it's the wife's KJ) for a little over an hour. First got in and saw the same normal thing with 5-10 mins before it started cooling. After it started cooling, it ran continuously, cold as ever, for the entire final 55-65 mins of my trip.

It's just odd that it won't start cold but then has no other fluctuation at all.

 

[Warren.fischbeck]

See if the clutch is engaged for the first five minutes or so of no cold air, it could be the clutch sticking and then engaging.

 

[HayaBuddha]

Is that the part that pops in and out on the front of the compressor? Sorry, not completely aware of all the terminology.

 

[Warren.fischbeck]

The clutch is the black part that the belt is wrapped around.

 

[Warren.fischbeck]

If the belt is spinning but not the rest of the black part, take a hammer or screwdriver and lightly tap the core part of the clutch to see if it kicks on.

 

[Warren.fischbeck]

Here's a photo

 

[HayaBuddha]

Okay, tried the broomstick thing and the light tap with a hammer both and neither started the thing going...we left it idling in the driveway and when it did start to get cold, looked again and the thing was spinning.

 

[Warren.fischbeck]

Do you have access to a refrigerient pressure guage? What is the high/low pressure of the system. Low side pressure should be between 20 and 30 PSI and high side should be between 150 and 250 PSI for this time of year. If the pressures are right, it could be too much oil in the refrigerient or the blend door is sticking/broken.

Take pressures pre-ignition, before the AC condensor kicks on and post the AC condensor kicks on.

 

[Porkchop]

Do you have access to a refrigerient pressure guage? What is the high/low pressure of the system. Low side pressure should be between 20 and 30 PSI and high side should be between 150 and 250 PSI for this time of year. If the pressures are right, it could be too much oil in the refrigerient or the blend door is sticking/broken.

Take pressures pre-ignition, before the AC condensor kicks on and post the AC condensor kicks on.

Ditto
Like I said earlyer have you checked the charge this will tell a lot of info and like someone else said if low add the dye and top off the charge and if the charge is good this too will tell a lot. Has it ever been recharged ?

 

[HayaBuddha]

Don't have access to a set of gauges but will go see if I can find someone that does today.

I had the entire compressor changed out about 3 years ago and it was charged then, obviously, but otherwise its never been messed with.