Hey guys -

My 1997 Ranger, XL, 2.3L, 4cylinder truck is having an A/C problem. All last summer while running the A/C the cold air will work but then suddenly warmer air comes out instead. After a while the cold air will come back. It fades in and then out. Any ideas as to what this problem might be? I do have some ideas but wanted to check others opinions? Hopefully this is an inexpensive fix. Thanks for the help.

FYI - No work has ever been done to the A/C system.

 

Keep in mind that your A/C compressor cuts out at WOT. So every time you step on the gas hard the compressor stops. This could cause temperature fluctuations, although yours seem to be more drastic than would be expected under that theory.

In addition, if your AC system is low on refrigerant, the compressor will cycle on and off (or not at all), potentially causing the same kind of symptoms.

Another thing to consider too is that the "default" climate control vacuum setting is defrost, meaning that if there is a vacuum leak somewhere in the CC system, the air is autmatically routed to the defrost vents. So check to see if the cold air is being diverted to those vents like that next time the problem occurs. Stepping on the throttle could cause a small leak to manifest itself like that.

 

Rockledge - Thanks for the reply. Yes, I was also thinking it was due to low refrigerant. Come to think of it now, the compressor does kick on a lot and is cycling more than it should. Is there some way I can charge it myself or will I have to bring it in and have it looked at by a automotive technician? If I can do it myself I will. Are there any special tools such as pressure gauges that I will need? I would hate to overcharge it. Thanks for your help.

 

Get a recharge kit from Auto Zone, Advance, WalMart, etc., etc. that includes a low (suction) side gauge in the charge hose, read the instructions carefully, and have at it. It will probably only take 1/2 to 1 can of refrigerant. I bought a small A/C thermometer at Auto Zone (~$5.00) that is handy for measuring air temperature coming out the center duct. My '99 Ranger will produce 38-46 deg. F. air out the center duct (in Max) when the outside temp. is in the 80's.
Piffery1

 

Thanks for the feedback piffery1. I will give it a shot. There is always a first time for everything. I appreciate the insight.

Kdwyer

 

I also wanted to point out that my A/C compressor clutch kicks in every 5 seconds at engine idle. Approximately 12 times per minute. When it kicks in it boggs the engine down for a brief 2 seconds then runs back to regular idle. The engine does not stall but it seems like it might want to. Do you think this is due to low refrigerant. I have never charged it and I am the original owner. The truck is a 1997 Ranger XL model. I want to add that this happens when the A/C is in use or when the fan blower is going for defrost mode .

 

That cycle time seems short to me, which could mean low R134a.

 

Yep, that's a really good indication of low refrigerant. Do you see any oily residue around any of the refrigerant lines connectors? If so, that's probably where the leak is occuring. I had to replace all the o-rings on my '83 F350 and my '89 Taurus but no signs of leakage yet on my '99 Ranger or '03 Taurus. I hope by now Ford has had a "better idea" and has fixed the problem.

Piffery1

 

Thanks guys. My next question is this. If the refrigerant is low, is this due to normal use? or is it indicative of a refrigerant leak. Just wondering as I hope it is not a leak. I will check for the oily substance when I have a chance. FYI - The A/C still cools pretty well when I do run the A/C system.

 

While the recharge of refrigerant is a good thing, my A/C has been dead about 1.5 years and my charge was good. No leaks, just constant click and not compressor noises...dead one day.

Check that WOT relay (in the underhood relay box) and check the cycling pressure switch, too!

I need to check my WOT real soon, since the troubleshooting chart in the Haynes leads me that way and points out that an AC that just "dies" is usually a sign of a toasty relay.

I'll be digging under the hood tomorrow and testing at least one relay.....

 

Refrigerant doesn't get used up, it either stays in the system or leaks out somewhere, usually a connections, sometimes at the shraeder valves, and sometimes through the hoses themselves (holes, splits, etc.) or compressor shaft seal or other components. With your '97 never having had any work done I'd say it's a pretty small leak and I really wouldn't worry too much about it. I'd just add about a half can and see how it does. Even with the old R12 systems many vehicles needed a can every 2 or 3 years and R12 had much larger molecules than R134A. I think you can get a R134A recharge kit for about $25-$30 at lots of auto or "big box" stores. Since the connectors are different, its impossible to charge into the high pressure side and blow up the can. The charge hose will only fit the low (suction) side fitting. Adding R134A with a recharge kit is fairly simple (read the instructions that come with it). Basically: 1. Attach the charging hose to the can tapper. 2. Attach the can tapper to the refrigerant can. 3. Remove the cap fromm the low side shraeder valve on your truck. 4. Advance the valve on the can tapper (clockwise) until it punctures the can plus about one or two turns. 5. Slightly turn valve counter-clockwise to purge the charge hose--then close off flow. 6. Attach charge hose to the low side shraeder valve and open tapper valve. Keep refrigerant can upright at all times when tapper valve is open. 7. Crank engine and run at approximately 1500 rpm. Open tapper valve about 1 to 1 1/2 turns to charge the system. 8. Watch the clutch-as the charge increases the number of cycles per minute should decrease (you should also feel the refrigerant can get cold. You may need to shut the refrigerant flow off every few minutes to allow the system to stabilize properly. 9. When you get adequate charge the cycles should occur much less frequently. 10. If your kit has a gauge, adjust the charge until the gauge reads the proper pressure for your outside air temperature. The Kit should contain a temperature/pressure chart to go by or the gauge may have a color segment to show ideal pressure.
Hope this helps. Piffery1.

 

Thanks again to all who provided insight into this problem. I believe with all the knowledge gained here I should be able to get this problem resolved. This is a great website. Happy Holidays to all.

kdwyer

 

sounds like its low on freon.

 

Hi Guys -

Thanks for all the input. I went ahead and bought a refrigerant recharge kit at Walmart. I checked and tried to charge the A/C system but it was not low at all. One thing I did notice is a oily green liquid (looks similar to antifreeze) on the a/c line that runs near the A/C cluth. The fittings at the end of this line are done with a special tool that I dont have. I think mechanics only have these. Any ideas why the A/C clutch might kick on every 5 seconds? It bogs the engine down for two seconds then goes back to normal idle and then repeats itself again. 12 times per minute total.

 

I forgot to mention this only when the A/C and defrost are turned on.