AC hiss, hot air - JeepForum.com
 
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post #1 of 6 Old 06-06-2020, 09:23 PM Thread Starter
coldspit47
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2004 WJ 
 
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AC hiss, hot air

Welp, title says it all. I've been without A/C for the last 4 years or so, but since I've been the only one driving it and I have a work vehicle, it took a backseat. Just found out my family is expanding and being without A/C simply won't do. I know there was some sort of leak when I purchased in 2014, as the service records included an A/C recharge more than once, so clearly there was a leak somewhere. Ice cold air for a bit, but after a while - hot air only. When compressor is engaged (including on defrost), the passenger floorboard hisses pretty constantly. The air coming through the vents is pretty close to ambient temps or warmer, depending on the day. Modes still function (floor, front, defrots, etc) and low-hi options react accordingly. Never dealt with A/C before so not totally sure what I'm looking for. I do know the compressor is not seized up and comes on when A/C is selected on the dash (manual temp control...it's a Laredo) but stays on, not cycling. Not sure what a leak would look like on refrigerant and hoping its not my evaporator core in the dash...Anyone have similar issues? From reading posts and Googlez it seems likely to be condenser or evaporator core, but again...no A/C knowledge.


04 WJ NV242, IRO 3in, bilsteins, IRO adj UCAs/LCAs/A arm, 265/75/16 Laufenn Xfit, 4.56 gears
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post #2 of 6 Old 06-07-2020, 06:08 AM
jtec
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add a can of refrigerant with a DYE, it is not suggested that a sealer or leak fix type product is added, just R134 with a dye... as the system cooling diminishes hopefully you will be able to see the leaking area.

Start rounding up the needed tools - gauge set- High and LOW, an AC vacuum pump.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #3 of 6 Old 06-07-2020, 06:27 AM
CJREX
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Not sure on the WJ, but on my Bronco the A/C hissed when the orifice tube was installed backwards.

If you have to get in to the system you might want to check that.

2004 Grand Cherokee Overland
2" BDS springs 265/70/17 Milestar Patagonia MT
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post #4 of 6 Old 06-07-2020, 07:49 AM Thread Starter
coldspit47
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Quote:
Originally Posted by jtec View Post
add a can of refrigerant with a DYE, it is not suggested that a sealer or leak fix type product is added, just R134 with a dye... as the system cooling diminishes hopefully you will be able to see the leaking area.

Start rounding up the needed tools - gauge set- High and LOW, an AC vacuum pump.
If, by some chance, the leak isn't visible in the engine bay, does that immediately point to evaporator? Any specific brands/types for the pump?

04 WJ NV242, IRO 3in, bilsteins, IRO adj UCAs/LCAs/A arm, 265/75/16 Laufenn Xfit, 4.56 gears
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post #5 of 6 Old 06-07-2020, 01:09 PM
Uniblurb
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Where there's a leak in your AC system typically you'll find the PAG oil they use for internal lubricant around a fitting or where it's leaking but often it's hard to see.

Agree with jtec and if possible buy a can of R-134A with UV dye but no sealer which can gum things up. But locally I've had a difficult time finding that and they all want to put a sealer in it.

Before buying anything check your local parts store like Advance and Autozone to see if they have any loaner tools like AC manifold gauge set along with AC vacuum pump. But typically I've never used a vacuum pump until I've fixed the leak then want to check to see if it holds vacuum for quite a while. But this is if you already know you have a leak.

Hate to say this but my 04 4.7 has a slow leak in the AC evaporator and I'll be redoing my whole system while pulling the dash, changing out the evaporator, heater core, etc..

How do I know the leak is in the evaporator? I bought the below AC sniffer tool which is an AC leak detector. The alarm on this tool doesn't go off anywhere else in the whole AC system except when I hold it about 6" above the front dash front vents after I've installed a can of R-134a. Plus my blend doors seemed to have AC oil soaked foam when I changed them out.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1


Amazon does sell a leak detection tool for $22 and the reviews seem pretty good.

https://www.amazon.com/gp/product/B0...d-b31d6b1bfbee

Some of those AC manifold gauge sets aren't very expensive but I'd read the reviews.

If you weren't going to use the can(s) of R-134a with UV dye in it I've used the below straight UV dye before. I just pore about 1/4 of the 1oz bottle down the yellow suction hose on the AC manifold gauge set before connecting the end to the can tap.

https://www.amazon.com/Interdynamics.../dp/B002M4G24U


The below UV pen light with yellow glasses kit make the UV dye in a leak easier to see.

https://www.amazon.com/dp/B003JOB594...xpY2s9dHJ1ZQ==

The sniffer tools are looking better all the time when you're talking about kind of messy dye, UV lights, yellow glasses, etc..

BTW, there's newer type AC cans of R-134a which have a rubber seal on top rather than the puncture type cans. Make sure you use the newer tap meant for sealed can rather than the older style puncture tap which won't work on the newer cans.

https://fjcinc.com/self-sealing-vs-p...d-accessories/

You want to make sure the hose is attached to the newer style can tap when screwing down the top valve since the refrigerant will flow as soon as the valve goes down. This is backwards of the old style puncture can taps since the valve on top would be turned to the left to open after puncturing and turning to the right would be closed. Thanks EPA for making this so dam complicated!

You're hissing noise could be the expansion valve being clogged or the leak in the evaporator itself if it leaks out quickly. I've found trees to be the greatest enemy of evaporators rotting away and leaking while highly suggest a cabin air filter to stop the tree crap, pollen, dust, dirt, from clogging up the evaporator fins. I did a write-up on installing the cabin/filter housing if interested.

You likely have the 04 FSM and I'd read through the section 24 on AC along with diagnosing problems. Also watching videos helps in charging, finding leaks, using AC manifold gauges, etc.. Lots of us are self-taught on AC including myself. As a safety note always wear safety glasses and wear rubber gloves when servicing an AC system.

Sorry about the book, there's quite a bit to cover on AC, and good luck.

Below is a performance chart on AC based on ambient temps and humidity. Good to know what the low and high readings are supposed to be along with troubleshooting in using a manifold gauge set. The revs up to 1,300 rpm when checking are for the 04 WJ and some of the other years normally it's around 1,100 rpm.
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post #6 of 6 Old 06-07-2020, 03:48 PM
Bigrigr
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If you get the dye in there and it is leaking from the evaporator core, it should show up in the evaporator drain hose(the one that drips water on the ground behind your passenger front tire when everything is working correctly).

If you are still getting the compressor to come on after 4 years of not servicing the system, then your leak must not be very big. The compressor wont come on unless there is a reasonable amount of freon to run it. Adding the single can of freon/dye should get you cold air, as you already have freon in there,and the whole system takes 1.5lbs total. Run it for a week or so after adding, then start looking for traces of oil/dye at all the fittings and joints in the hoses. Dont forget to check the condenser itself behind the grill, as it is susceptible to rock damage from other cars.

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,4" short arm lift,JK'sW/32's
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