94 Ranger - Do I have an AC leak or what??

[dorough]

My AC was fine until a week or so ago. Not much air was coming out, and the air I was getting was not nearly as cold as it used to be. I figured I was low on coolant since I could hear the compressor clutch clicking in every 5 seconds or so. So I gave it a R-134a coolant charge and immediately felt the ice cold air coming out again and the compressor clutch cycled much slower.

As luck would have it, the next morning the blower motor completely gave up the ghost before I could even get on the road. So a couple days later, I replaced the blower motor along with the motor resistor and cleaned a handful of leaves out of the evaporator case.

So now I'm thinking new motor, new resistor, charged system... time for some cold air! Nope. I have plenty of air blasting in but it's not cooling at all. And the compressor is back to the fast cycling again. So where do I begin to look? How do I know if I have a leak or if it's something else? And if it is a leak, what's the best way to find it? I'm not an AC moron, but I ain't no AC rocket scientist either, so whatever you can throw my way to chew on I'll appreciate!

 

[Stoodybayker]

Cycling compressor is s sign of a low charge....sounds like you have a leak, and it's getting worse. There are leak detectors that you can put in, and use a UV light to see where it is...but the most likely place is the compressor seal.

 

[dorough]

I guessing the compressor seal would be the seal around the shaft? I should be looking first of all for leakage on the front of the compressor?

 

[4x4junkie]

That would be there I'd start looking for sure. Other places to check though are the hoses, and the spring-lock fittings where the hoses are connected to the condenser, as well as the one on top of the accumulator/drier (fairly frequent spots for it to leak).

Usually you will find an oily residue around a leak, so be looking for that if you don't have a detector.

 

[dorough]

Ok, I finally found time to check this problem out a little more. I haven't found any visible signs of AC refrigerant leaking anywhere. The compressor was still cycling pretty fast - every couple of seconds - and the pressure was cycling up and down on the gauge. So going under the assumption that the refrigerant level was low, I hooked up a can of refrigerant. As it went in, the compressor cycling slowed down and eventually stayed engaged full time with a constant pressure reading of 28-30psi. So I got in the truck to check the air temp and it was slightly cool... not cold by any means. Granted, it's almost 100 degrees today, but I would still expect it to be colder. Additionally, I never noticed any condensation on the AC lines... not sure if it wasn't going to form or if it would've just needed more time. I only let it run 5-10 minutes. Any ideas what I'm dealing with here?

 

[dorough]

--UPDATE-- Well, this morning after driving about an hour, the air seems to be maintaining its coolish temperature - not getting any colder, but not getting any warmer either. So now, I'm wondering... is it possible that it's just really low on refrigerant? The truck is 17 years old. Could it be that maybe there was a tiny leak somewhere and the little bit of refrigerant I just added - which, by the way, had leak sealant in it - plugged the hole?

Along the same lines, if the system is low on coolant, combined with the fact that I don't want to overcharge the system - could it be that I'm just not filling it up enough? I see all the warnings about DO NOT OVERCHARGE YOUR SYSTEM. Again, I'm not an AC whiz. How do I know if it has enough in there or not? And how do I know if it's being overcharged? The fact that it's holding its slightly cool temp makes me wonder if I just need to add more. I only put in about 3/4 of a 7oz. can between the last two charges. And the label on the evap coil box says Max. 7 lbs. Should I put more in without fear of overcharging?

 

[press 1 for english]

--UPDATE-- Well, this morning after driving about an hour, the air seems to be maintaining its coolish temperature - not getting any colder, but not getting any warmer either. So now, I'm wondering... is it possible that it's just really low on refrigerant? The truck is 17 years old. Could it be that maybe there was a tiny leak somewhere and the little bit of refrigerant I just added - which, by the way, had leak sealant in it - plugged the hole?

Along the same lines, if the system is low on coolant, combined with the fact that I don't want to overcharge the system - could it be that I'm just not filling it up enough? I see all the warnings about DO NOT OVERCHARGE YOUR SYSTEM. Again, I'm not an AC whiz. How do I know if it has enough in there or not? And how do I know if it's being overcharged? The fact that it's holding its slightly cool temp makes me wonder if I just need to add more. I only put in about 3/4 of a 7oz. can between the last two charges. And the label on the evap coil box says Max. 7 lbs. Should I put more in without fear of overcharging?

Why don't you do the proper thing and check the pressures when charging so you don't overcharge?????????????
The proper amount of refrigerant charge is listed on the radiator support bracket and should be 2 lbs or so.

 

[dorough]

Interesting stuff going on here. I just took it for a ride (in the 100 degree heat!) and noticed that the compressor cycling was back to every 2 seconds. BUT when I stopped the truck and let it idle, the compressor stayed engaged and there was a slight cooling to the air coming in. Took it back on the road... warm air & fast cycling again. So is this definitely sounding like a refrigerant leak now to anybody, or no?

 

[press 1 for english]

Interesting stuff going on here. I just took it for a ride (in the 100 degree heat!) and noticed that the compressor cycling was back to every 2 seconds. BUT when I stopped the truck and let it idle, the compressor stayed engaged and there was a slight cooling to the air coming in. Took it back on the road... warm air & fast cycling again. So is this definitely sounding like a refrigerant leak now to anybody, or no?

Put a freaking set of gauges on it or live with the heat until fall.

 

[dorough]

Hey Press 1, did you see the part where I said I'm not an AC whiz? I'm guessing not. Thanks, though, for your sarcastic remarks. Hopefully somebody here will have some answers without attitude.

 

[fordforlife]

the best bet is to totally remove all freon and fill with the right amount with dye and shot a black light on the system including the high and low side valve to find any leak. it would help to know both the high and low psi reading while is fast cycling. it is possible the the pressure is to high or to low and the sensors are telling the compressor to shut off to avoid possible damage to is self. hope this helps.

 

[dorough]

the best bet is to totally remove all freon and fill with the right amount with dye and shot a black light on the system including the high and low side valve to find any leak. it would help to know both the high and low psi reading while is fast cycling. it is possible the the pressure is to high or to low and the sensors are telling the compressor to shut off to avoid possible damage to is self. hope this helps.

It absolutely helps... thanks! I'll try to get those readings. I don't have a set of gauges, just the psi gauge that came will the refill kit from AutoZone. Are the top/bottom psi readings pretty much standard on all vehicles, or is it vehicle specific? Just wondering what I should be expecting.

 

[dorough]

Ok, so using just the pressure gauge that came with the refill kit - attached to the low pressure side - as the compressor cycles it was going from 60psi down to 23psi and back. However, when the AC was turned off, the pressure gauge shot up to over 100psi - way up in the red. Is that normal? Does any of all this ring a bell with anyone? I know I might sound like a dummy, but I'm trying to learn a little bit about all this AC stuff, and any help from you guys is appreciated!

 

[fordforlife]

on that refill kit the red most of the time means that the system is over full. however that also depends on what the temp is out side.
also knowing the high side pressure helps determind if there is a blockage in the system. and pressures are different for all vehicles the rough spec for your truck is low side 22-50 psi and high 160-250 psi. this with the out side temp at 80F. also remember that the max charge on the system should be no more than 22 oz for you ranger which is 1.37 lbs of r134a

 

[dorough]

Thanks for your reply. Do you know if there's any sort of adapter that will let me attach that gauge to the high pressure side? Or do I need to find a set of 'real' gauges?