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AC problems

BKennedy

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Elite Explorer
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Location
USA
City, State
San Diego, PRofK
Year, Model & Trim Level
1994 XLT
I have had no luck with the AC in the Explorer. I know, you are thinking, open the windows, you don't need no stinkin' AC. Well, I might love the wheelin', but still like the comfort of rolling up the windows and cooling off when its hot outside.

AC quit working about a year ago.
Replaced; hard line that goes across engine to compressor was leaking, evaporator was cracked, bad compressor. $1,300.00 and change.

Worked great until a few months ago, now the compressor won't come on. I hot wired the pressure switch that won't allow the compressor to activate if the pressure is too low and compressor works fine. No cold air, so must have another leak somewhere. One month after the warranty ran out too. I think something might have been knocked around and started leaking when I rolled it awhile back.
Any suggestions before I take it back to the shop?:(
 



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Ac

Did you convert it to R134A? If not put the kit from the Auto store in to the system and then ad the Leak detector Dye to it. The r134a will allow you to check your system yourself and most of the kits have the gauge for the correct pressure. The die will show up if you have a leak somewhere and let you know. If you have a leak, the R12 is mostly gone and it is outrageously expensive and illegal to work with unless you have the liscense. You can also buy a vacum pump from Harbor freight relatively cheap and vacum it down to around 20-24 or so and watch the guage. if it moves to a lower number you definitely have a leak. All that work is not fun and maybe cheaper, but it is not easy work and the knowledge has to be gained by research.. The system will need to be purged with a cleaner and that should be done by a shop with tthe right equipment. Good luck
 






1994 is already r134a from the factory.
 






Vacum will only tell you have a leak, not help you find where the leak is. Pressurizing the system is the only way to accuratly find a leak. I was hoping someone knew something I don't about this stuff so I could find the leak without taking it to a shop. I don't want to fill it up only to have it all leak out again.
 






Moving this to the AC forum where you will get better help
 






I have a '94 (the AC wasn't working for about a year)......I ended up replacing alot of components, while chasing a leak and on the advice of the shop (compressor hose, accumulator, orifice, compressor, evaporator, low pressure switch). The last time the shop looked at it.....they claimed it was a vent door problem (which it wasn't).

Anyway, to make a long story short. I bought a manifold gauge set and a vacuum pump, to attempt a DIY job. Going to the shop was getting too expensive. DIY....I was still not happy with the results (filling the system with 24 oz of R-134a. - as per the sticker on the AC evaporator box).

So, one day.......I started the process all over again.....evacuated the system (vacuum) and put in 24 oz. of R-134a, it was still warm. So, I released some (thought, maybe I over filled it) and then since it still wasn't getting cold, I added more and I kept adding, until I got.......Low pressure 30 and high pressure 250. It was like 82-88 degrees (ambient air temp).......the lowest vent reading I got was 44 degrees.......but, the system liked to stay at about 50 degrees. I guess thats "good enough."
AND
Today, as I passed the bank (in my vehicle at 44 degrees).....the sign said it was 86 degrees outside........gee, I'm happy now.

And, now that I have had time to reflect on this project......I figure it's FORD's fault. The sticker in the engine compartment said MAXIMUM 1 lb. 8 oz. (24 oz)......it never got cold. The shop was doing what the sticker said (so, perhaps, that was the main reason). IF, the shop followed the book or NAPA (both said 36 oz.)......I may have gotten the joy I was seeking. Not to mention, the shop guy only evacuated the system until it just hit 29. Now, after reading, I know why it needs to be done for a longer period of time. Though, in the end, the FORD engineer responsible, should get a big kick in the b*^^ for that mistake (and quick detach fittings, on the fuel and AC lines).

All in all, another good reason to DIY (if you're willing to shell out for the tools).

Aloha, Mark

PS.....the compressor won't come on....think....low pressure switch, replacement.
 






If the air isn't cool while hotwiring the compressor, the low pressure switch isn't necessarily bad. You need to run a quick check of the pressures, the tool is dirt cheap at a parts store.

Anyway, call some AC parts stores and find the quick connection lock kits(aftermarket). All AC systems since the early 80's have quick connections. Those all have o-rings in them, and they vibrate constantly. Those o-rings wear out much much faster from vibration than age. Kits used to be available for about $15 for each size, and included the o-rings.

Find out what size connections you need, and thus kit sizes, then when you get to an AC shop again, have those replaced. Each connection can be serviced in less than five minutes, the 95-01's only have a couple, my 95 Crown Vics had five on them. Everyone with a 5+ year old vehicle should have those aftermarket connection locks installed.

Bottom line is that you may have another issue, or leak also, but I bet big money that those o-rings are leaking too. Good luck,
 






Good point.....use only the new style A/C green colored "o" rings.

Don't know how much you wanna spend (for the shop to do it - labor). You could (if the system has been evacuated or has lost all of it's pressure/charge) DIY, along with changing various components (don't forget the AC oil). Then, take it back to the shop to be recharged w/ R-134a.

Aloha, Mark
 






Let me add... as for an O ring lubricant I HIGHLY Recomment NYLOG.
 






If the air isn't cool while hotwiring the compressor, the low pressure switch isn't necessarily bad. You need to run a quick check of the pressures, the tool is dirt cheap at a parts store.

Anyway, call some AC parts stores and find the quick connection lock kits(aftermarket). All AC systems since the early 80's have quick connections. Those all have o-rings in them, and they vibrate constantly. Those o-rings wear out much much faster from vibration than age. Kits used to be available for about $15 for each size, and included the o-rings.

Find out what size connections you need, and thus kit sizes, then when you get to an AC shop again, have those replaced. Each connection can be serviced in less than five minutes, the 95-01's only have a couple, my 95 Crown Vics had five on them. Everyone with a 5+ year old vehicle should have those aftermarket connection locks installed.

Bottom line is that you may have another issue, or leak also, but I bet big money that those o-rings are leaking too. Good luck,
I already replaced most of that stuff last year, when I replaced the compresser, evaporator, hard lines and some other stuff. I already hot wired the low pressure switch and the compresser comes on, but it blows warm air.
 


















What's wrong with my Air Conditioning?
A number of things can happen to make your A/C quit working. Here, we'll go over some of the common problems, and what you can do to fix it.

Leaks / Low Refrigerant
No A/C system is completely, 100% sealed. Over the years, small refrigerant particles will leak out, up to 1/2 ounce per year. On smaller-capacity systems, this will become noticeable a lot quicker than a larger capacity system. In this case, the most practical thing to do is simply add a bit more refrigerant. You will want to hook up a set of manifold gauges to make sure that the system has at least some pressure in it before you add refrigerant, because if the system is completely empty, you might have a most severe leak. At best, you will still have AIR in the system, and you want NO air in there.
Symptoms of low refrigerant include rapid cycling of the compressor clutch, or clutch will not engage, little or no cooling, very oily spots on A/C components.
A severe leak will require repair or component replacement. To find a leak, there must be some refrigerant in the system. An electronic 'sniffer' or dye are the most effective ways of finding a leak. Most A/C shops can perform this service for a minimal charge. Some retail auto parts stores also loan or rent tools for this.
Once the leak is identified, the component should be repaired or replaced, and the system serviced.
*Tip* - Evaporator leaks can be difficult to find, since the evaporator is usually not easily accessible, located in the dash of the vehicle. With dye in the system, place a white, preferably unused baby diaper under the evaporator drain tube. Moisture will drip on to the diaper. If there is dye in there, you'll know it!

Poor Airflow
One of the most-missed problems is poor airflow. Your A/C comes on, but it's not very cold. If you have a gauge, the high side pressure seems awfully high.
There are a couple of quick, easy things to check. First, make sure the condenser is debris-free, and that the fins are not all bent over. The condenser is located right in front of the radiator. Bugs, rocks, plastics bags, etc. covering the front of it prevent air from passing through, cooling not only your radiator, but also the refrigerant in the condenser.
All engines have either a fan clutch or radiator / condenser cooling fans. Fan clutch go out all the time. The fan clutch is located between the radiator and the engine, and has a big fan blade attached to it. With the engine on, that fan should be turning very fast, and moving a lot of air, TOWARDS the engine. Running correctly, you will not want to get your fingers near it. I recently repaired a 1996 Chevy truck that had blown the compressor shaft seal. While diagnosing the system, I noticed that the fan was barely turning. I could actually stop it with my hand. (not recommended for the non-professional) Because there was poor airflow, the pressure (pressure is temperature) built up from the condenser to the compressor, and was more than the compressor shaft seal could handle.
If the vehicle has an electric fan, make sure it (or they) comes on, and that the air is fast, and moving TOWARDS the engine. If the fan(s) does not come on, check the fuse. If that's not it, you may need to replace the fan.
*Tip* - You can confirm proper airflow by TEMPERATURE TESTING. A good thermometer that can be touched to the inlet and outlet of the condenser will confirm proper airflow. You should see a 20 to 40 degree drop from the inlet to the outlet of the 2 condenser pipes. For example, if you measure the temperature at the inlet (where it comes from the compressor) and have a temperature of 160 degrees, the outlet should be 100-140 degrees. Less than 20 degrees difference usually indicates poor airflow. MORE than 40 degrees usually indicates a restriction in the condenser.

Restrictions
A restiction is a condition where some piece of debris has lodged in a component, and is 'restricting' the flow of refrigerant. Condenser restrictions are the most common. Most late-model condensers have very small passages, as low as 6mms! When there is a restriction in the system, the flow of refrigerant is greatly slowed, or sometimes stopped completely. The blockage causes pressure to build up behind the restriction, and will cause damage to the components behind it.
The most effective way to locate a restriction is with temperature testing. With a good thermometer, temperature (which is pressure!) can be measured ANYWHERE on the system. Large drops in temperature can be identified and repaired. For example, a restircted condenser...If the inlet measures 160 degrees (about 295 psi) and the outlet measures 90 degrees (about 103 psi), it means the refrigerant is slowly leaking past a restriction. Because the refrigerant spends more time in the condenser, it has time to cool of more. Problem is, that 295 psi will continue to build back, and will eventually blow a seal somewhere, probably in the compressor.
Some restrictions can be repaired by flushing the restricted component, but parallel-flow condensers usually need to be replaced.

Improper Refrigerant Charge
As A/C systems become smaller and smaller, the amount of refrigerant in the system becomes critical. The correct charge for an A/C system has been calculated and engineered by vehicle manufacturers for optimum performance. Here are some tips to keep in mind when charging a system:
Charging with cans: A 12 ounce can of refrigerant gives you 12 ounces of refrigerant, right? Well, not always. If you are using a gauge set to charge, those hoses can hold up to 4 ounces of refrigerant themselves. On a 56 ounce capacity system, those 4 ounces might not make a big difference, but on a 1 pound system, you can bet it will. Also, notice how when you pull the can tap off, how the can wasn't quite empty? Yep, another ounce or 2 there.
Too much! Your A/C isn't quite cooling, so you run down to the parts store or a big box retail store, and buy a recharge kit. We in the industry call 'em suicide kits. You add a can of refrigerant. Well, with A/C, too much isn't better.
Retrofitting: Vehicles manufactured prior to 1993 and some 1994 originally came with R12 refrigerant. Because of the cost of that refrigerant, most folks opt to retrofit to R134a refrigerant. Problem is, there is no set standard for how much R134a refrigerant to use in an R12 system. There are many misconceptions about how much to use, and some people have come up with percentages of original charge. I've heard to use as little as 60% of the orginal charge!
So how do I know if I have the proper charge? Our old friend temperature testing can help determine if you have the proper charge. Orifice tube systems are the easiest and most accurately confirmed systems. It can be done on expansion valve systems, but you'll need to get on the evaporator side of the expansion valve.
Here's how: Measure the evaporator inlet pipe and record your temperature. Now measure the outlet pipe of the evaporator. Those 2 temperatures should be as close to equal as possible, at least within 5 degrees of each other. If the outlet is MORE than 5 degrees warmer than the inlet, you still need more refrigerant. If the outlet is MORE than 5 degrees cooler than the inlet, you have too much refrigerant in there.
Final tip: If your A/C is working, don't mess with. If you have an R12 system, you do NOT need to have it converted to R134a just because someone tells you that R12 is gone. If it's working, leave it alone.
If your system is working and sealed, you DO NOT need to replace your filter drier or accumulator. This is not a part that wears out. The only time you need to replace it is when the system is opened, or if you've had a leak that allows air (and moisture) into the system. If someone tells you you need to replace it every 3, 5 or 7 years, they're trying to sell you something.

_______________________________________________________________________

From:

http://reviews.ebay.com/A-C-Diagnosing_W0QQugidZ10000000000946036

_________________________________________________________________

If you're saying that you have a leak in the condensor*......then, the only thing left, is to change it. But, IF, you're saying that there is a leak somewhere and you can't find it.....that's different. Go, back to finding the leak.

Sniffer, dye, pressure or vacuum test.

*If you replace the condenser don't forget the oil. IF nothing is replaced.....the system's total capacity for oil, is 7 oz.
_________________________________________________________________

Once you've found the leak and fixed it.

The usual way.......is for the system to be evacuated (vacuumed), the old R-134a and some oil will be recovered. (IF the plan was to replace parts, then go ahead and do it, don’t forget to add oil to the individual parts that you replace.) Part of the evacuation procedure is to check if the system will hold the vacuum. IF the vacuum holds, it's OK to proceed to refilling it with R134a and some oil. Oil is replaced on 1 for 1 basis. R-134a is replaced based on the system's capacity (see sticker in the engine compartment, AC book or NAPA chart). IMHO.....don't use "R-134a w/stop leak"......use ONLY pure R134a.

http://www.napabeltshose.com/news/index.cfm?location_id=1078&id=1517&show=newsitem

IF you overfill the system w/ oil or R-134a.....it could lead to more problems. Having the correct capacities of oil and R-134a in the system ensures "one less problem" to deal with.

IF the vacuum won't hold......a sniffer or dye may be needed to find the leaky parts and then have the parts replaced. Oil is introduced to the specific parts, at installation time. Once the parts are installed....vacuum again. If the vacuum holds, then it's on to the re-charging.

Typical Re-charge:

http://www.explorerforum.com/forums/showthread.php?t=158183


Note: IMHO.....If the system is opened or was empty or if the accumulator is over 5 years old......replace the accumulator and orifice tube........save yourself from the future problems.


For the '94 Ford Explorer......The Haynes book says........at ambient air temp of 80 degrees F, hi velocity fan in front of the condenser, 1500 RPM.........22-50 low side and 160-250 high side pressure.

If you see that the compressor isn't working when it should (you said it's new)....think......low pressure switch on the accumulator.

Aloha, Mark
 






If you see that the compressor isn't working when it should (you said it's new)....think......low pressure switch on the accumulator.

Aloha, Mark
I already hot wired the switch to get teh compressor to activate and its still blowing warm air. There is some pressure within the system because I tried it by letting a little out. I am just going to send it to my brother's shop and have them figure it out. I can do all sorts of vehicle repairs, just not this one. Thanks for your help.
 






I'm not sure if you have them out there (you could always mail order it) but Harbor Freight Tools sells a leak detector for < $100.. When on sale they are $50ish.. It will make finding the leak much easier, then you only have to buy the right part to fix the leak..

There are only a few special pieces needed to do the a/c yourself.. its much cheaper than getting it done.

Manifold set (I got mine for $39), vacuum pump (evacuator).. I've used the venturi style a few times with my air compressor ($29).. It works, just not as easy to use as a real evacuator pump ($300 but I've used it on about 7 a/c jobs now), and a leak detector (makes finding the leak so much easier).

detector - http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92514
manifold set - http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92649 (on sales as of today, just print the page and take it into the store if you have one local).. you will still need the connector that goes between the r-134 can and the yellow hose, but thats a <$10 part at almost any auto parts store)
venturi style evacuator - http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92475 (on sales for $10 as of today) - You do need a decent a/c compressor to use it.. I use my craftman 30 gallon 6hp compressor..

~Mark
 






I already hot wired the switch to get teh compressor to activate and its still blowing warm air. There is some pressure within the system because I tried it by letting a little out. I am just going to send it to my brother's shop and have them figure it out. I can do all sorts of vehicle repairs, just not this one. Thanks for your help.
I think maybe I wasn't clear about the "think....low pressure switch." See, there is pressure in your system (as you tested). But, it (system pressure) maybe too low.....for the switch, to switch on, the compressor. The switch activates within a range......turning on and off the compressor, based on the system's pressure. Though, I guess you know that. The switch may (or not) be the problem (or just another problem) with your vehicle's AC. I suggest you find leak and re-charge it, before going on to the switch question. It could also be other things (note: post #13).

ME.....I wouldn't "hot wire" a compressor switch in an effort to permanently fix a problem. Then again, I doubt that you intended a "permanent" fix w/ the jumper (hot wire). The "hot wire" comments that one usually sees (ref. to bypass the low pressure switch when recharging a system) is only a temporary measure to help get R-134a sucked into the system (enough, to bring the system pressure up.....so, the compressor will operate). But, I guess you knew that too.
________________________________________________________________________________________

OK.......story time. I was "thinking" that my low pressure switch wasn't working. Cause, after I had "fully charged it," I didn't see my compressor switching on and off w/in a set time period. I purchased the new switch and I unscrewed the old switch. Well, the valve behind the switch started leaking out R-134a. I couldn't get the switch back on, to stop the leak. So, I went back to the auto parts place and bought a replacement valve. By then, all of the R-134a had leaked out......so, I was back to square one. Was this THE LEAK that I was looking for?

Anyway.....whatever you do....GOOD LUCK.

Aloha, Mark
 






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