AC Not Cooling Well

shop stated readings were 30/230 100+ degrees outside.

I understand your advice, yet it is paid for , gets 35 mpg. For me it is worth putting some $ into, vers car payments. thanks

On that note, I see your point.

35MPG ain't bad at all.

Good Luck!

Good call on checking the damper (once checking the system vitals). That definitely can take the chill out if it doesn't close all the way. I checked Autozone dot com and they don't mention a damper actuator or "motor" but they do list this heater valve.

As I'm a V-dub person, I can't really tell you where this critter is located but I suspect it is near the firewall on the passenger side. The adjustment of the cable may not be fully closing it when you crank the temp dial all the way to cold.

Good luck with your quest.

I agree you should be getting WAY colder than that. I have an 89 civic and I can get cold enough for frost to form on the windshield OUTSIDE on a humid day if I turn it max cold on defrost.

Of course I have properly evacuated my system and got a proper R-12 charge in it....just rebuilt it completely 2 years ago.

Heres a question....did anyone ever squirt in a sealer into the system in the past you know of?

As others have asked....what are the pressures you are running at hat ambient temp..and is it R-12, R-134 or one of those crappy blends that are everyplace?

Some of possible causes for not cooling are below:-

· Clutch not working

· Evaporator frozen

· Compressor drive belt slipping

· Low on refrigerant charge

· Low suction pressure

· Expansion Valve frozen

· Plugged receiver drier

At that age, I would definitely rule out a slipping clutch.

My BMW ended up having a stuck Heater valve open, and a low charge....

I don't go to mechanics, they seem to hose you every time.....

Troubleshoot, Troubleshoot, Troubleshoot.... Then make your repairs....

Cheaper that way.... and labor is free.....

I have a similar problem occurring with my wife's 2004 KIA Sedona van. Yesterday I attempted to recharge the ac system with 134a. The pressure read almost 40 psig for a few seconds then dropped to zero thereafter. The ac system is still blowing hot air.....this has been happening since we replaced the blown engine.

Could this indicate a leak of some sort? I don't have any die to inject into the low pressure port. Frustrating at best just to get at the port because there's very little room available to work.

Does anyone here know of any good online methodical troubleshooting resources that are downloadable?

I don't trust too many auto mechanics out there because most will hose you but real good......they can see you from a mile away coming!!!!

If it dropped to zero...you most certainly have a leak....

And a fairly big one at that. Do you have acess to a tank of nitrogen you can pressurize with that, and you should be able to HEAR a leak that bad. THats what the HVAC pros use to find leaks....and a thin soapy mix to look for bubbles.

I'd look at the condenser up front first....and the compressor second, then follow everything else and pray its not the evaporator as those are a HUGE PITA on most vehicles. Except my '89 Honda Civic Hatch where I can drop it out in 15 minutes. (Yes I've done it in that time)

I don't know if I'll be able to hear a leak of any type if the engine is running w/ the ac on max.

In regard to finding a leak in the condenser or the compressor, what should I be looking for there? Should I be looking for leaks using the watered-down soapy mixture and checking for cracks in rubber hoses, seals of all types, and bi-metal lines as well? There's plenty of oxidation on the metal lines.

Problem is, there's not much room in the engine compartment to get at a lot of these parts.

No, I don't have access to a nitrogen tank and not sure where I'd find one locally + how to hook it up to the low pressure charging port.

I think you can get refrigerant that has dye already in it. Once you use it and it leaks out, you can use a small UV flashlight to see where the dye came out. Auto parts places may have loaner lights.

Good idea and thanks!

bob c, I did all that and did see the pressure gauge go to 40 psig (@ 65 degrees F) when I attempted to recharge it (initially the pressure was zero when I attached the 134a can equipped with apressure gauge and hose), then fall to zero pressure. I couldn't hear the leak because of all of the engine noise.

I guess I'll have to get some die and inject it. I just hope it isn't the compressor that's gone bad!

Thanks!!!

The compressor is usually an easier item to replace than the evaporator. Before the dye, try dumping a can of freon in with the engine off. If the can is inverted, the liquid entering the A/C system will have a large expansion rate, and should allow you to hear the leak area. Another option would be to add a can of refrigerant oil instead of the freon. The oil is easier to find because of the oil staining. Good luck.

Two problems with that....sorry, didn't see this until now.

#1. Invert the can on the low side service valve on a running system and you slug the compressor and destroy it.

#2. Put oil in for the sake of putting oil in a system (resulting in an overfill) thats running will slug the compressor and destroy it.

You do not need to have the engine running to find a leak as large as you appear to have. With the engine off, attach the can of 134A, and allow the pressure in the can to push itself into your A/C system. If the ambient noise level is low, you should be able to hear the leak.

If the freon is coming out as fast as Capt is saying, do you really think his oil volume is still correct?

My reply was to Capt Moosie. His problem is much different than the OP.

it could be moisture in the system. ice could be clogging the expandion valve. try vaccumming the system then recharging it.

Okay, how does one go about "vacuuming" a vehicle AC system?

This is really the first time I've ventured into working on an AC system, so please bear with me....

If your system will not hold pressure, it will not hold a vacuum. How long did it take for the 40 psi to drop to 0?

There are vacuum pumps specifically designed to lower the pressure in a refrigerant system. It is connected to an A/C system in place of the can of freon. Once the system has pulled a sufficient vacuum, and it is able to hold that vacuum, freon and oil is allowed to enter the system. The idea is to lower the pressure and cause the moisture to boil itself out of the system.

Hey Bob, the pressure drop occurred within a second or two duration.

Unfortunately, I don't have a vacuum pump. Do you know where I can buy a cheapo one online that can be fitted up to the low pressure port?

Q: Can I hook up the charging hose that I have (w/ pressure gauge & valve) to the low pressure port, without the can of 134a attached, and bleed the system that way by opening-up the valve?

If the pressure dropped within seconds, you have a large leak. The total volume inside the refrigerant system is not that large. If you added a 12 OZ. can of liquid freon, it would expand many times the volume of the can it was in. For that to have dropped to 0 that quick is a serious leak. Start at the fire wall and examine the large hose leading to the compressor. Examine the compressor, then follow the smaller line forward to the condenser in front of the radiator. Continue examining the small line as it runs back to the fire wall. What you are looking for is oil stains, or any physical damage that would have allowed the freon to leak out.

What you have not examined at this point is the evaporator. It is buried in the duct work of the HVAC system. BUT, there is a drain to allow condensation to drain out to the ground when the system is working. Find this drain. Expect it to be under the plastic duct work, close to the fire wall. It should have a rubber hose like end on it, and be about 1/2" diameter, aiming down. Examine this for oily residue. Something somewhere is allowing the freon (for this lecture, I am using the word freon when the correct word is refrigerant) to leak out. Because the lubricant is circulating with the freon, it will leave oil stains where the leak is.

If you can not find a leak by this method, I would suggest that you drive to an experienced A/C repair facility for an exam. I can tell you that the common quote is a compressor, dryer, evaporator, expansion valve, and possibly the condenser. So that means that he will jack up your fan switch, and install everything else. It will solve the problem, if your pocket is deep enough.

Lets look at the individual components.

The compressor is a piston pump. It usually leaks at the shaft seal a slight amount no matter how new it is. It may also leak at the point where the hoses attach. It might also leak at any switch that is mounted to it. Mechanically, it should have no play in the rotation of it. With the engine OFF, the center of the compressor at the belt end should be able to be turned with no free-play when reversing directions, and no clunking. If none of the conditions presented themselves, we can give the compressor a preliminary OK.

The dryer. It contained a descent. Any time the system is opened for any amount of time, ( my rule is over an hour) it needs replacement. This device also collects any trash that has come loose in the refrigerant system. So you need to change it for 2 reasons.

The expansion valve, or orifice tube. both serve the same function. Both also have a screen in the direction of freon flow. If there is metallic debris in the screen, the compressor is bad. If the expansion valve screen looks clean, I would suggest that you only clean it in A/C system flush, and reuse. If you have an orifice tube, just toss it and use a new one. They are that cheap.

The condenser. It is made fairly robust. It has bugs, chewing tobacco, birds,bugs and slow pedestrians slamming into it all of its life. If you can not see anything wrong with it at this time, let it ride.

Hoses. Hoses are custom made for all factory A/C systems. They can be repaired in most cases, but, all that can go wrong with them is they leak. Examine them closely, and you will know if bad or good. The exception to this is sometimes the factory will install the orifice tube in the line from the condenser to the firewall. This line may have to be cut apart to replace the orifice tube. The good news is that you can not become pregnant from this "procedure". If you have this design, you just have to replace the line.

That leaves the evaporator. The evaporator is the radiator like device that transfers the coldness of the freon to the incoming air. By design, it is a thinner material, and more prone to corroding out, and leaking.

SO.... if you have a repair facility define the leak in your system, you can decide from there what else you want to change, "because it is just as old".

Find the leak first, and then we will help walk you though the land of A/C. Good luck. If there is a vocational school near, they might diagnose it for a reasonable fee, and no salesmanship classes.

i use a compressor from a refrigerator in a pinch. a good compressor will pull a vaccumm compable to a high priced vaccumm pump.

there are vaccumm pumps specifically designed to evacuate the freon. the vaccumm will also evaporate any water in the system.

Guess:

Non condenseables such as water from not being vacuumed or some junk got in the lines when they were opened plugging the orifice/expansion valve. Or the drier wasn't replaced when the system was opened.

i ran into the same problem but is was caused by a worn pump that clogged the screen with metal particals.

Metal particles are sure to be internal parts of your compressor. That is why a thorough flushing is needed whenever a compressor failure happens. An extra filter is also a good idea.

OK, an update. THANKS for all advice

I am using 134a, Shop claimed 30/230 pressures in a 95 degree shop.

I have replaced everything except condenser in the last 3-6 months. My coworker told me to do some homework on this. He told me to put thermometer in vent, check temp. then run a water hose over condenser with ac/engine on. I did & it dropped inside temp 20 degrees. I'm hoping condensor replacement will be last of repairs, at least to the ac. Also, when I replaced evap/ and heater cores, I checked that all blend doors were working properly.

Thanks again.

Before you throw more parts at this thing, try some simple testing. There are two A/C lines on your compressor. the larger one is the suction line. It should be cold with the system running. With a thermometer, the temp should be below 50 degrees. If that line is cold, it has to be the cold air not getting into the interior.

If the condenser was "bad" it would have to be a restriction in it, not allowing sufficient volume of freon to remove the interior heat load. If there is a restriction, the High side pressure would climb way over the 230, and the compressor would suck the low side pressure below the 30 reading. Additionally, if there is a restriction in the condenser, the restriction point will act just like an expansion valve, and create a cold spot in the condenser. Look for the cold spot. My guess is that you will not find one.

If your back is against the wall, and you are feeling pressured into the condenser replacement, negotiate a commitment from the repair facility. "If the condenser does not cure the problem, no charge for the repair, or at least, no charge for the labor." Force the repair shop to stand behind his guess. If the condenser is replaced, insist on having the old unit returned to you, Paint some nail polish on it so it is not switched. A good condenser should not have significantly more restriction than the restriction caused by a hollow tube of the same inside size as the connections on the condenser. Good luck. Let us know the results of the above tests, and we will further narrow it down.

I'm mostly with Bob C on this. The 30 PSIG suction sounds kind of low, especially at idle standing still, so it could be slightly undercharged. And the 230 PSIG discharge sounds a little high, but maybe ok in 95 degree still air. Even a properly operating AC will perform better with a colder condenser, which is what you provided with the water, so this doesn't really prove the condenser is bad. Check that the air flow through the condenser is good - make sure the fins are not bent up, it's clean, any and all fans are operating at full speed, and that any fan shrouds are properly fitted.

Normally, with insufficient air flow across a condenser, the high side pressure will climb into the 350 plus range.

clean the condenser "cool", by spraying it with a mixture of ammonia and dish soap using an ordinary spray bottle. wait for a few minutes then spray it using a garden hose. be careful not to bend the fins. shine a flashlite through it. the light should shine through the other side if not, repeat the process

if this does'nt fix the problem, take it to the garage.

A simple question for ya: IF I inject a can of AC dye into the low pressure side of the system, do I absolutely need a UV lamp to discover where the leak originates, or can I see the leak point with my Mark II eyeballs?

TIA!

Well, it depends pal. If the leak was big enough, you could see the hole with just your Mark IIs. but as the leak gets smaller, the Mark IIs need help. With the A/C system having oil circulating with the freon constantly, when there is a leak the easiest thing to do is look for the oil stains on the refrigeration components. That is why I suggested a can of oil as a way to look for the leak. Adding the dye will create a greenish yellow oil stain. That should be visible, if the leak is decent. But, if your leak is indecent, the UV light will make the due stand out better. You stated that the freon went to 0 very quickly. If it drops that quick, the leak should be easier to find.

Bob, many thanks for the advice! GA as well!