96 3.0 ranger ac - slow to cool

[98v70dad]

My ac is pretty slow to cool especially in slow traffic. I checked the charge and it was low. It took a half of a tall can to get it in the middle of the charged range. It now gets much colder but still takes 15 minutes to get there. I live in the Deep South so it can take a few minutes to cool off a car but 15 is way longer than what seems normal. Anyhow, I'm wondering if Rangers had a problem with the ac clutch slipping and how to fix that. Mine is engaged enough so it doesn't look like its slipping - but it could be. It's hot here and I'd really like to is this if anyone has any ideas for me.

 

[adsm08]

Do not trust that it is charged properly. Take it to a shop and get it charged correctly.

 

[RonD]

Yes, +1 to ^^^^

If its HOT then charge pressure needed changes, you don't mention any pressure readings???
Chart here: http://rechargeac.com/how-to/ac-system-pressure-chart

 

[JerryC]

Try cleaning your condenser first, it's probably accumulated lots of bugs over the years.

 

[98v70dad]

Sir, if you want and need help.. we can't see or feel what's happening so it falls on you to provide as much information possible.

Temp outside? actual low pressure? actual high?

I'll look at the pressure tomorrow and the temp, etc. I would rather take this to a shop but I have a 40 mile commute and no other way to get to work. My wife is in the same situation. I can't be without my ride for a day without taking a vacation day.

BTW, I know that you can't help me without information but I didn't know what might be needed.

As I recall, my low pressure side reading was on a 90 degree day was right about where it should be according to your chart. I put some 134a in about a month ago, so if its leaking my pressure readings may be low again.

 

[98v70dad]

Yes, +1 to ^^^^

If its HOT then charge pressure needed changes, you don't mention any pressure readings???
Chart here: http://rechargeac.com/how-to/ac-system-pressure-chart

Thanks, I'll check the gauge when I get home, but my memory tells me that the pressure on the low side was 35 psi on a 90 degree day. It was right in the middle of the "low" band on the DIY bottle I bought. Now its right in the middle of the "good band". I don't really trust those recharge kits too much except for a little "tweak" to the pressure.

 

[98v70dad]

Did the AC ever work "fast" on the truck? 134A refrigerant is not a fast responding medium like the old R12 systems where it takes 3 to 5 minutes just to start cooling and sometimes even longer to get and stay in operating pressures starting out in a very hot vehicle sitting in the sun it's going to take a while to cool off.

No idea how fast it was when new - its 21 years old and I got it in October. I had a 96 Crown Vic and remember that was it was slow to cool but not nearly as slow as the truck.

Has the truck ever overheated? The truck was my dad's and I know that it never overheated.

Does engine temp get hotter when sitting in traffic? No.

Florida has billions of bugs flying around, check your front condenser and Grill area and see if it's matted or covered and reducing the airflow through it, I'm in Atlanta Georgia which is a 6 hour drive from Florida and there are no more bugs here than PA (I'm from around Pittsburgh but also lived near Philly) although I'll check the condenser and see if its clear.

If the truck runs hot, consider getting a Extreme Performance fan clutch. The truck doesn't run hot. The temp gauge is exactly where it should be and I monitor the coolant temp with a ultragauge- usually no more than a few degrees above 200 F.

You're not going to be very successful with a hand-held AC Pro gimmick charging cylinder. Maybe not that's why I asked about it. I had a left over half can from another car and adding it increased the low side pressure to roughly where it should be and it significantly improved the AC performance. The car is 21+ years old but only has 60,000 miles on it.

First guess is you may need just a few ounces more.

 

[98v70dad]

Well if you still want to try and fix it yourself,
try a these things, ok?

you're going to need a thermometer, not a infrared gun, just a little dial thermometer I think they're less than $10.

Block or turn the idle screw to an RPM about 1200 when you're checking air conditioner.

With the thermometer, see what temperature air is coming out of the vents, it should be 15 to 20 degrees cooler than the air in the truck.

With your hand, check the refrigerant line between the evaporator and the accumulator that should be cold and sweating.

What throws off people's thinking when checking the air temperature, they don't understand the air coming out will slowly get colder, it will never drop immediately down to 45 degrees.

Example, 90 in 70 out, 80 in 60 out, and so on as it gets cooler inside the truck. As the temperature drops, the TD(temperature differential) will still be 15 to 20 degrees lower than the air going in, on ac systems. This is why they freeze up when they get below 65 or so. generally auto systems don't freeze up because they have a low pressure control.

while doing the above, if the engine fan doesn't make lots of air noise it's not moving not enough air.

One more last thing you need to check is the flapper door inside the heater, Ford Ranger heater core is always hot on the older ones and there's a door that blocks the hot from the cold. You can find the controls for that behind the glove compartment door.

I don't like that setup so I have the heater core bypassed for summer.

I like your heater bypass. Thanks, but I know all the info you posted and already checked those items - all checked OK. As I said in my original post, my AC works, it just takes a long time to get there. Also, I need to run it on max to get it there a little faster.

 

[98v70dad]

if you use copper tubing on the bypass tube make a small flare on the end to keep the lines from sliding off because oh high pressure.

Remove the fan and fan clutch and install a high-volume electric fan if loss of cooling in traffic bothers you

You checked all those things.... Right,

wish you well

Actually I did check all of those things. Here are the numbers:

35-40 psi on the low side at 85 F outside ambient (mostly 35 psi but the needle wanders up and drops back occasionally).

with the AC on MAX the temp at the register is 41 F at 85 outside ambient and 1200 rpm.
with the AC on AC the temp at the register is 56 F at 85 outside ambient and 1200 rpm.

All the other things you mentioned were also OK. The coil could always be cleaner but its not encrusted in bugs and dirt - I'd call it about normal.

I'm not completely helpless, I appreciate that you responded to my question but you gave me advice about things I'd already checked, I just didn't have the numbers in front of me this morning because they were on a slip of paper in the truck. Now you have them. Still wondering about the AC clutch and whether its slipping or not.

 

[JerryC]

I think if you had a high side gauge on there it would show the pressure fluctuating as the clutch slipped. If it was a constant slip the pressure should read low, assuming everything else is good. But I wouldn't expect it to slip for very long before it was just flat worn out and not working.

Regarding the condenser, when I rebuilt my ac system last year the condenser looked "ok" until I pulled it out and from the backside I could see all of the bugs jammed in there. I replaced my condenser so I can't tell you if just cleaning it would have been fine our not.
I think Eric the car guy did a YouTube video of using pro grade coil cleaner on a car condenser.

 

[98v70dad]

I think if you had a high side gauge on there it would show the pressure fluctuating as the clutch slipped. If it was a constant slip the pressure should read low, assuming everything else is good. But I wouldn't expect it to slip for very long before it was just flat worn out and not working.

Regarding the condenser, when I rebuilt my ac system last year the condenser looked "ok" until I pulled it out and from the backside I could see all of the bugs jammed in there. I replaced my condenser so I can't tell you if just cleaning it would have been fine our not.
I think Eric the car guy did a YouTube video of using pro grade coil cleaner on a car condenser.

Thanks. I don't have a high side gauge but I've been thinking about getting a gauge set so I could check that.

The truck sat in my dad's garage for 20 years and he never drove it. I got it about 6 months ago. So if the clutch is slipping its in the process of getting destroyed this summer as I drive 100 miles to and from work in 95 F heat every day. That is the reason I asked about it. My situation is unique - old truck no miles on it, now being driven daily.

There have been lot's of little half working things that have popped up in the last 6 months that weren't a problem for dad because he drove the truck maybe once a week. Stuff fails when its old (regardless of the mileage) when you start using it every day.

 

[4x4junkie]

I don't think you have a slipping clutch... Like said before, if it was slipping, it'd likely give up completely almost immediately and then you'd see the compressor rotor not spinning at all. Usually they just simply fail to engage at all when they get too worn.

The numbers you posted earlier (41°F on Max A/C and 56° on normal A/C) are well within normal, especially if that was with the truck sitting still. The 15-minutes part though I'm not so sure about what would cause that (unless it's because it takes you 15 minutes to get from surface streets to a highway or freeway when it starts to get colder, in which case I would agree, your charge level is probably low).

Hopefully whatever product you used didn't contain leak sealers...
What I would suggest is check the temperatures of your evap inlet (lower) fitting, and then the outlet (upper) fitting. (an infrared thermometer works well for this) With a proper charge, they both should be quite cold, and within 5-10° of each other on a warm to hot day. If the upper fitting is considerably less cold (55° when the lower fitting is 38°, for example), it is because the refrigerant charge level is insufficient, and is fully boiling to a vapor before any of it has a chance to reach the accumulator.
Fill it until the upper fitting becomes cold like the lower, and you should then be good (you should be able to tell right away too, it'll turn very cold quite rapidly once the liquid (boiling) refrigerant reaches that level).
If it still isn't working satisfactory after that, then yeah you'll need to get a proper gauge set and see what your pressures are in relation to temperature (the high-side in particular), and go from there (it's possible you could have some contaminants in there).



The A/C systems on these trucks work exceptionally well when they have the correct amount of charge... The air on my '94 gets very chilly cold within 30 seconds after I start it (it is R-134a), and within maybe 5-10 minutes, I'm turning the fan down because it's freezing my ass off. My '90 (converted to R-134a) is also much the same way, just that it takes a little longer to cool down it's larger interior space.