recently noticed that the a/c in my truck is considerably warmer than it used to be. still blows air but it is definitely not cold as it should be.

need to know if I have to find a leak or do I get the recharge kit and recharge the system. read the only thread related to this through the search option and it looks like I must have a leak if the coolant has leaked out.

Any suggestions please and thank you. The quicker the better have a 3 hour drive in what looks like 90 degree heat come tuesday morning.

 

Have the refridgerant checked. If it's low then there's probably a small leak. U can also just get a can and add it first to see if that helps. I believe there's a safer method of leak checking today than the old propane method. New leak detectors on the market for the professional.

 

It can be dangerous & get costly if you overcharge an AC. Every parts store & WalMart should stock recharge kits w/low side gauge & basic instructions. A quick check w/such a gauge will help tell you if the system needs to be recharged, or is full, indicating another problem.

If there's a leak, I'd check all the connections 1st to be sure they're all tight. R-134 refrigerant w/system leak sealer & UV dye is also commonly sold. The sealer can stop small leaks in hoses & rejuvenate a marginal seal, at least temporarily. When UV dye leaks its easily detected using a UV light, sold on the same rack.

However if the guage reading shows the system is full the compressor might be failing & I'd suggest having high side pressure checked. You may also suffer FORD's 'blend door' gremlin, where AC is fine, but the 'blend door' fails to close, inappropriately bleeding hot air directly thru the heater core.

 

I was at meijers late last night, bout midnight, saw the recharge kit and saw a lot of other refrigerant bottles with a lot of different names. how much would a a/c system check cost? i know if the compressor and is there something called a condensor isn't it an expensive fix?

 

close all your doors, turn to max AC with the car running, install a thermometor in the vent. Allow a couple of minutes. The temperature should be 15-25degrees below ambient temperature. Low side pressure is a good thing to check, You can start by verifying that the compressor clutch engages when you turn the switch to Max a/c.

There is a professional way to diagnose this system, but you go buy a can of r134a with a low side gauge on, and you can easliy top off the system. Some people just do that instead of fixing, basically plug the gauge in, and allow the system to reach its full lowside pressure. It should be somewhere in the 30-50 psi range based on ambient temperature and humidity. Good luck .

 

I'd expect a thermometer in the AC vent of a good running system to read below 50 degrees. If the ambient temp was 90 I'd consider "15-25degrees below ambient" a poor result & sign the AC needed help. The charts on 2 common recharge kits list low side pressure as 45-55 psi at 85 degrees w/50-55 psi at higher temps.

Some recharge kits have throw away gauges. I'd suggest buying a guage that can be reused. There are 2 common DIY types; one has a dispensing trigger & requires matching refills that have a valve in the can of refrigerant, the other uses the standard 'pierce' type cans of R134.

 

What should I hear when the compressor clutch engages when i switch to max a/c?

I'm going to go ahead tomorrow and purchase the kit, go to the auto parts store and start asking questions.

thanks for the quick reply, i'm fine with driving with the windows down but besides the a/c problem and i believe a bearing in the steering column the truck is perfect.

 

you have to look at the clutch on the compressor and make sure it engages. you are correct, my 15-25 degree spec is what i would expect on an average 70-80degree day, But you also have to remember there is an ambient temperature, to inside temperature relationship. I would not condemn an a/c system for only reaching 65degrees on a hot 90degree humid day ( I would hope it would be a little colder, but I am looking at a minimum spec) . An a/c system is only able to cool as good as the environment it is in.

The professional way of checking an a/c system in the way described, would be to have a large shop fan blowing cold air over the condensor. Only then can you really expect to see the best results.

 

i went to Wal-Mart and bought a blue hose about 8 inches long that has the low side coupler on one end, and a squeeze handle with bottle screw head on the other end. There is a cheap gauge 0-200 psi built into it. You couple the hose onto the low side fitting and the gauge should read about 110 psi with motor off. Start motor with AC on max and compressor will kick in and gauge goes down to below 40 psi. You cant read the high side unless you have a second gague. It is about 200 psi. See if the clutch will stay engaged 90% of the time at idle and if the pressure is around 35-45 psi. If the pressure drops below 25 psi, the compressor will cut out. Probably means your low on gas. Now screw on the R134 bottle. Remember not to sqsueeze the handle with the R134 bottle off. When the bottle is screwed on 2-3 threads, tap the handle slightly and let a small burp of R134 come out of your system, and push any air out of the hose , around the bottle threads, then screw the bottle on all the way. squeeze the handle and the gas starts flowing. NOrmally put in 1 can and you will get 35-45 psi and clutch running most of the time. See if the clutch will stay engaged MOSt of the time when you rev the motor to 1800 rpm and hold it there for a minute. See that the air in the truck "feels" cold. Normally about 50 degrees. Your truck is 7 years old. Not uncommon to leak out a can over a few years. Might not be a real "leak", just needs a can added every year or two.

 

Those quick refill kits should be banned. You no idea how many overcharged systems I have run into because someone used those kits. You do not fill an AC system using the low side pressure. Instead you monitor both low and high side pressure, and adjust for temperature. The system is full when the high side reaches the target pressure.

 

Not to mention most of them have leak stop, which likes to circulate throughout the system, and harden up inside every component when you have to eventually find the real leak because its too big to be plugged.

 

I'm still apprehensive on the kits i'm going out here in a bit to find a place who can service it hopefully today.

 

If you do want to service the system yourself, you need a manifold gauge set and a thermometer. You measure the ambient air in front of the condenser, as your reference. Then you slowly add the refrigerant to the system monitoring the high and low side and the relationship to each other. When the target high pressure is reached, the system is now fully charged and running at peak efficiency.

 

I would like to thank you all for the plethora of information you have provided on the subject. However, I did choose the safer route for me in fixing this.

Took it to a local belle tire and they recharged the system. I asked them to change the o-rings and they changed the ones that didn't require mass amounts of labor, those going to and from the condenser, one was torn and the other they replaced because it was easy. The o-rings were shot so in my opinion I guess it was a good idea to take it somewhere instead of spending 40 dollars on the do it yourself kit to work to no avail.

Thanks again. Now that bloody steering shaft/steering column bearing.

 

So, will the clutch continue to engage/disengage until a certain pressue is reached?