AC Problem ... Please Help Me !! | Ford Explorer Forums - Serious Explorations

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AC Problem ... Please Help Me !!


Well-Known Member
September 15, 2009
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City, State
Year, Model & Trim Level
1992 Explorer 2wd
I just purchased a 92 Explorer and the ac didn't work, so I put freon & then the compressor engaged. The clutches were super worn & it barely put out a little cool air for just a few minutes, then when I would rev the motor a little the pressure relief would open & I could smell freon coming out ... this happened for about 10 mins. then stopped opening , but the ac didn't cool afterwards any. It has held pressure for about 2 weeks now but wouldn't cool. The compressor still cycled and with the gauges hooked up it was right on the high/low pressures listed in the Haynes AC manual ... so I went to the junkyard & bought another compressor that had good clutches & swapped it today ... put oil & freon ( I put the 134 conv. adapters on by the way ) & it cooled decent at first ... nothing to brag about, gut cooler than before ... anyways rev the motor & same thing with the pressure relief valve then its barely cool again, but showing proper pressure high/low again. I evacuated the system before filling it also.

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the lines are getting cold also & when I removed the old compressor it still had full freon charge in it ... I just don't understand what the problem could be.

I live in AZ and just went through a similar problem this last week with my 91 EX. Did you replace your fixed orifice tube? There is a good chance that and/or your condenser might be clogged and part of your high pressure problem from a previous compressor failure. Also our 91-93.5 Explorers used R-12 which uses a Motorcraft part #YF49 Compressor Pressure Relief Valve located on the compressor manifold. This is a "short" one and only about 1/2" long. It has a lower pop off point (about 350psi). The 93.5 and up 134-A systems use a Motorcraft part #YF50 Compressor Pressure Relief Valve. This is considered "long" and about 3/4" in length and has a higher pop off point (about 450psi). I picked mine up at the dealer for $22 and found out that once they pop they need to be replaced. They are the same threads and swap right out. While your at it pick up a receiver/dryer from for about $25, a Fixed Orifice tube for $1.00, and a Spectra premium Condenser for about $80. Buy these items for a 94 model since they all bolt right in and were designed for 134-A. 134-A and R-12 condensers are different and 134-A is a "thicker" refrigerant. The R-12 condensers are a dual pass where the 134-A is a single pass and supposed to be more efficient. If you buy the 94 receiver dryer you will also need a 94 clutch cycling switch since the threads are different. I think it was $28 from a local parts store. My lines are the 93 style and my suction line runs across the front of the engine. I installed my own parts and then went to the AC shop to have it charged up. Took 3 times at the shop to figure out the condenser difference and why the Pressure Relief Valve would work fine then pop off after sitting for about 10 minutes. They took care of me and didn't rape me on the diagnostic charge. I think they were just as puzzled as I was about why it was acting up. Having owned my EX for 10 years, put 120K on it, and had 3 black deaths in 240K miles, this time I had to replace everything but the evaporator. I used Pag 150 oil and put 4oz in the suction side of the comp and 4oz in the receiver/dryer. The other day at 108* outside my temp gauge (a small meat thermometer) in the center vent registered 38*. NICE!!

38 degrees ... awesome !! thank you so much for the info ... unfortunately I don't have the $ for the extras right now ... but, hopefully I can get a piece here and a piece there soon enough to get it going before winter !! as for now I guess my $14.99 Autozone fan will have to make do !! ... do u think theres any chance the higher pressure 3/4 would be enough to get it semi going ? cuz it was fairly cool before it spat it out of there !!

I may be able to get by a lil cheaper though through my buds Autozone business account ... I think I will just stockpile everything until I can do it all at once, so I know its done right !! and no I didn't change the orifice tube or anything other than what was mentioned ... I do have 1 more ? though ... Autozone listed an inline changeable filter, but the only thing I see resembling this is a small round canister on the drivers side thats pressure fitted lines on eacdh end with no way to remove the filter?

Oh ... apologies ... I forgot to thank you for your time Buford ... very much appreciated !!

No problem, I don't mind saving someone else the frustration I went through. The small cylinder you were referring to is a muffler for the compressor and I don't believe they are used on the 134-A lines.

Also, I would not personally mess around with one of those aftermarket inline filters. All the crap is supposed to get captured in the receiver drier. The only problem is that most of the solids will plug up the orifice tube first. Having said that, if you have solids floating around your system then you have a compressor failure happening and no aftermarket in-line filter is going to save you from that.

so I need to take the muffler line off & replace it with a 94 ^ line ? also what about the condenser ... you listed an $80 one ... would a factory one from a 94 ^ not work ok?

Also, I would not personally mess around with one of those aftermarket inline filters. All the crap is supposed to get captured in the receiver drier. The only problem is that most of the solids will plug up the orifice tube first. Having said that, if you have solids floating around your system then you have a compressor failure happening and no aftermarket in-line filter is going to save you from that.

You mean like this? :)

The compressor on our '92 is going bad. Been going bad for a few years. The compressor clicks when its running and you can tell the seals are going out as the high pressure is lower than it used to be.


Black Death on a Variable Orifice Tube by maniak_az, on Flickr

The explorer is on the list of vehicles to have the entire A/C fixed. The van needs all new parts (they were removed) and the Explorer, well, you can't really get black death out of a system.


OMG !! I didn't exactly understand his comment about black death ... what is all of that crap & where is the orifice tube located ?

Since everything is r12 your going to need to convert to 134a you will need....
94 compressor
94 accumulator
94 pressure switch
94 condenser
94 suction line
94 liquid line
94 134a orifice tube.
At a min you can get by with just the compressor, accumulator, & orifice tube. BUT you have to flush everything else completely & even then AC life is only a few years.

Mccoyxx, The orifice tube is located in the liquid line where it connects to the Evaporator. It is the small diameter line on the pass side. It's actually located inside the inlet of the Evaporator. If you remove the liquid line (7/8" wrench I think) you will see a small tab sticking out from the middle of the evaporator inlet tube. If you pull it out with a pair of needle nose pliers you will have the Orifice tube. If you have never attempted a full on AC repair by yourself you might want to have a buddy on hand that has experiance to assist you. Like most mechanical repairs, if you do it once you will have the basics for the future. I agree with Jason94sport, to be absolutly sure you wont have problems or will be re-visiting an AC issue in the near future, it might be best to just replace everything for a 94 that is already set up for 134-A.
Maniak is right about trying to remove the Black Death and thats why it's best to buy NEW parts and not try to get by with wrecking yard stuff that you dont know the history of. When I half-assed the repairs the first time in WA things seemed to work well for the 9 years I was there. It would only get between 85* and 95* a few days a year. When I came to AZ thats when I was paying for my lack of knowledge and trying to just get by 9 years earlier. Last year in AZ it didnt dip below 100* for over 2-1/2 months... even when I closed the bar down at 2:30am it was 104*. Basicly things worked well in WA because the load on the AC system was nothing compared to here in AZ. I'm not sure what the summer weather is where you so you might be able to get by, but is it worth the risk? I just priced everything on minus the AC flush @$17.00, Pag150 oil @10.00, and clutch cycle switch @$28.00. Rock auto was $304.21 and the extras were $55 for a total of $359.21. I had Summit racing price match Rock Auto so the ship charge was free.

I just purchased both A/C lines, a dryer, and a condenser for a 94 for my 1992 for $184 including shipping from RockAuto. Hoses and dryer got here today, condenser should be here Friday. My compressor was replaced by the previous owner (family friend) at the same time they put on the 30 dollar conversion kit. My current condenser has hole in it. I am going to pick up the orifice tube, oil and refrigerant at Autozone, drain the compressor and put it all together this weekend. Vacuum and charge, hopefully in this humid GA heat it will throw ice cubes at me. Did I miss anything? Four oz of oil in the lines and four in the dryer, is that correct?

Flush your evaporator really well before you put anything in & don't forget the o rings. The fittings should have them on but make sure & also lube them.

Unometooo, remember to check your 92 cycle switch compared to the 94 accumlator/dryer. The threads from my 91 cycle switch were different than the 94 accumulator /dryer threads. 4oz in the suction side of the compressor and 4 in the accumulator/dryer is what I used.

Coming down to the wire. I went ahead and purchased a comp works compressor new from Autozone, I figured if I am replacing everything, might as well replace it too. The only thing I'm not replacing is the evaporator. I dont know what kind of PAG to buy. They have low, med, and high viscosity oil. And I also can't figure out how much coolant to put in. Will the basic Autozone refrigerant be sufficient?

It was recommended to me to use the PAG150 oil. Unless you have the proper equipment to pull a vacuum and recharge your AC I would just bolt everything on and go to the AC shop and have it done professionally. You've already spent enough time and money to replace parts so why take a short cut on the most important part? Besides in order to charge it properly you need to have quality vacuum pump, a set of gauges, and not let any air or moisture into the system. If you're buying individual cans to charge the system, everytime you disconnect one and hook up another you're letting air and moisture in the system.

Personally, I'd just buy an a/c vacuum pump (not the kind that connects to your air compressor) and a manifold set. IIRc I paid < $175 for the pair of parts years ago..

I pay about $7 per can of r-134 (I still have a case at the house).. so its cheap to do.. The manifold/evacuation pump have been paid for in savings multiple times over.

Once you have an evacuation pump you can then evacuate the system yourself which will pull out the moisture etc out. I usually pull a vacuum for 30 minutes or so (its not humid here) and then let it sit for 30 minutes to make sure its holding. If its not I start looking for leaks before I charge the system.

Now when you charge the system using the manifold set and the little cans you just need to bleed the yellow line (center) before you run the r-134 into the system. Before I started to do the work myself I used to take it to shops and they always used the little 12 ounce cans and that is where I learned about bleeding the line. I've seen them press the shrader valve on the center line and others just loosened the line. They would let the "air" out until they saw r-134 and now the line is purged.


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ok everyone thank you for all the help ... as I said I am on a narrow budget, so I just replaced the pop off valve with one for a 95, changed the orifice tube (which was unbelievable ... worse than the one above !!) ... put some pag 100 and freon & its working great !! its pretty cold, but it doesn't feel like it blows very hard to be on high .... I put about 3 cans of freon, but I think it could use about 1/2 can more ... I know its probably not going to last, but its the best I could do for what my budget allowed ... if it lasts the summer it was worth it !! I am going to try to get a 4wd before winter anyways, so I will probably sell this one soon ... thank you again everyone ... God Bless & take care !!