To clarify, the air flow through the vents is good, but it is not cold?

I'd have a licensed AC auto technician check the pressures. It might be just low on "freon" which also means it may have a leak.

 

The air flow hasn't changed and is good. The two silver pipes that go into the air box are cold, the larger one and the smaller one. My understanding is if you have cold you have freon. I maybe wrong but if it's 85 here and the pipes are very cold.

 

These use a fixed orifice discharge tube in the line instead of a conventional expansion (H-) valve. The low pressure (cold) in the system should occur right after the orifice. The line should be warm leading up to that point.
If the pipes are cold, the problem may be that the temperature blend door in the HVAC box isn't swung to the full cold position, allowing a blend of warm air? Diagnose first.

 

Thank you for you assistance. That does sound like the blend door could be culprit. I've also had problems with one drivers side vents producing more heat/cool than the passenger side. I concluded that there must be a door that governs this for vehicles that have the feature of selecting temps for driver/passenger side and this vehicle just has the door set to the center and maybe it's shifted.

My problem is that I can't find an assy drawing of this particular air box so I have no idea where to start looking for doors. Any drawing I have found are for the hard top models which seem totally different from the convertibles.

Best regards

 

From your previous post regarding the inferred sensor I noticed two types of a/c-heater controls where one has a center knob as a driver/passenger blend control so maybe on to something. If I could find a breakdown of the air box and distribution assy drawings I would be able to get under the dash and figure it out where the door are.

 

. . . .2011-200 with A/C that's always worked perfectly ..till today. A/C comp is operating and the two silver pipes that enter the heater box under the hood are dripping cold. Lots of air flow out of vents, any suggestions please. . . .

Here is a link to some documents from HVAC service for a 2008 Avenger. The Avenger is the twin of the 200 so I would expect the A C information to be the same.

Dropbox - Avenger HVAC - Simplify your life (at https://www.dropbox.com/sh/h5yzy8id70l39di/AAC12CKdO0OSWJ0MPrCOFmT9a?dl=0 )

From your A C system description you have separate controls for the driver side and passenger side of the vehicle. In the documentation it shows driver and passenger side controls linked together. In your vehicle will find actuators on the passenger side of the HVAC plenum box which control passenger side blend door operation (temperature control). Review and see if this information points you in the proper direction.

I would caution you to first check system performance of suction and discharge pressures. As mentioned you could have a low refrigerant charge (performance pressures low) and this could be causing variations in temperature between driver and passenger side. Attached chart indicates general pressures to expect from the vehicle A C system when proper refrigerant charge present.

 

Thank you and running the vehicle for 10 min, 85 degrees and high humidity the main silver tube that runs to the fire wall has thick layer of frost all over so I have to assume the freon side is ok. I now have to find a friend with an a/c (or cool) garage and hire a trained chimp. I will report back when I have something to share.

 

. . . running the vehicle for 10 min, 85 degrees and high humidity the main silver tube that runs to the fire wall has thick layer of frost all over so I have to assume the freon side is ok. . . . . .

Frost on the suction line at the firewall is the TELL-TALE sign that the system is low on refrigerant. A low refrigerant charge causes the suction side pressure to drop to a level where the expansion and evaporation and state change from higher pressure liquid refrigerant to lower pressure gas refrigerant is happening below 32 deg F. Below 32 deg F you will get frost. Ideal refrigerant charge situation is to have the suction pressure / temperature relationship above 32 deg F.

Add a small amount of refrigerant with the A C system operating and you will see the frost melt on the suction line as the line temperature goes above 32 deg F. Monitor suction and discharge pressures as you add refrigerant according to the chart in post #7.

 

My observation, both silver lines should not be cold. The smaller line runs runs liquid from the compressor to the condenser in front of the radiator to the evaporator. This line should be warm. The liquid turns to gas in the expansion valve and evaporator so the cold gas flows into the evaporator and cools the air. The small line being cold indicates the system is low on refrigerant..

 

Thanks, if both silver line should not be cold then I will top up with freon. Many thanks again.

 

Can I assume it's R134? I don't see any stickers under the hood.

 

. . . Can I assume it's R134? I don't see any stickers under the hood. . . .

Yes the vehicle uses R134a refrigerant. The service ports use quick disconnect fittings with the discharge service port larger than the suction service port.

 

I would first verify that the refrigerant charge is, in fact low with gauges before just adding refrigerant.
If it is low, fix the leak first.

 

Hmm, maybe I should have read your last post sooner. I purchased an Interdynamics A/C Pro 20 oz recharge kit, watched the you tube videos and happy to say I now have AC. I suppose the worst thing is it runs out and back to square one, maybe get couple of years or couple days at least I'll know. The kit comes with a gauge and read low, filled it till it got into the green and the air worked fine. I noticed when switching the ac off the gauge went into the red, would this be the freon pressure equalizing as I am on the LP side?

 

When A/C is off, the high and low side pressures eventually equalize, correct. So the low would appear overcharged at that time (or in the red).

 

Thank you so much, now it's waiting game to see when or if the pressure drops. The vehicle is 8 years old so maybe get another 8 years. We will see...

Thanks again to all that has answered to this.

 

Never blindly fill the system with one of these kits. Overcharging can be dangerous.

And please don't refer to a professional mechanic as a trained monkey. They are my friends and are well-educated, skillful and honest. It takes a lot of work to get to that stage.

 

I never blindly do anything, Charging gently till it just gets into the green and cold air comes out is quite acceptable imo especially when reading and understanding how it works and abiding by all the safety concerns.

I mentioned a trained chimp, with reference to getting down and under and reaching up behind the heater core on the floor and squeezed in front of the front seat. Was referring to a small statured person, wasn't meant to insult your friends. Maybe should have said "pint-sized"

 

We will agree to disagree. A manifold gauge set must be used, along with a chart of pressures vs ambient temperature (or full evacuation and refill of the specified amount of refrigerant). Putting an unknown gauge "into the green" area is operating blindly. Hope it works out OK for you.

 

Ambient temperature and air pressure do alter the amount of pressure for the a/c system.

I looked up the system and it looks like a poorly developed system I also have - https://amzn.to/2KUFz6g - bought it on a moment of weakness (for much less $). It's not really the right thing to do the job well, and I regret getting it (for something like $10 at some car parts store).

If I wanted to really do it on the cheap I'd buy one of these, at least, which can use standard R134a cans ... https://amzn.to/33VXBg9

A gizmo like this would be more appropriate... but still not ideal... Search Results For "a/c r134a manifold gauge set" (at https://www.harborfreight.com/search?q=a/c%20r134a%20manifold%20gauge%20set )

Really, if you don't have a leak, just pay a pro $100 and get it over with. If you do have a leak, pay a pro to fix it or at least get the pro to evacuate the remaining refrigerant, then find and fix the leak, then pump out the system thoroughly and refill it.

 

I invested $50 in that gauge set, and $100 for a vacuum pump probably 7 years ago, and have used it at least 1/2 dozen times. It still works great, and results are great. Not always the case with Harbor Freight, but this equipment can be trusted.

 

Sometimes they have surprised me by having higher quality than expected. I think a better bet than Amazon's selection of “let's use an algorithm to create company names” Chinese manufacturers.

I suspect most of us do not have your patience and skill for working with a/c. Certainly you've gotten your money's worth, probably the first time you used them.

 

Thanks Bob, we will agree to disagree. How often do gauges fail, to me then renting a manifold set from say, AutoZone, your dealing with unknown gauges, who knows what idiot or not idiot used it last, was told by the AutoZone rep. that faults in equipment are sometimes not reported fear of not receiving there deposit back and they certainly don't check them. Anyway buying a new R134 top up kit and putting the new gauge on the LP side and registering low pressure then slowly bringing the pressure up to just in the green doesn't seem like a big issue to me.

If you have a leak, go to a professional. Just talking about topping up the system.

We should bring this to rest for others who want to top up there a/c systems, who read and who do understand the mechanics of what there doing and abide by the safety rules shouldn't have a problem doing this.

Would like to hear from others that disagree with this.

Regards.....

 

Thanks Bob, we will agree to disagree. How often do gauges fail, to me then renting a manifold set from say, AutoZone, your dealing with unknown gauges, who knows what idiot or not idiot used it last, was told by the AutoZone rep. that faults in equipment are sometimes not reported fear of not receiving there deposit back and they certainly don't check them. Anyway buying a new R134 top up kit and putting the new gauge on the LP side and registering low pressure then slowly bringing the pressure up to just in the green doesn't seem like a big issue to me.

If you have a leak, go to a professional. Just talking about topping up the system.

We should bring this to rest for others who want to top up there a/c systems, who read and who do understand the mechanics of what there doing and abide by the safety rules shouldn't have a problem doing this.

Would like to hear from others that disagree with this.

Regards.....

I don't consider a dial with red, yellow and green 'zones' with no numbers, to be a gauge. Nor did you state that you had a pressure vs temperature chart available. It's common, but it's a hack method that can damage the system. To me, if it's worth fixing at all, it's worth doing it right and not risking taking out the entire system for the sake of a cheap shortcut.
Not to mention, if you've ever blown out a hose or the high pressure relief valve, you really don't want that experience. And then it requires a lot of money or professional intervention.

 

The simple fact is you can't know the health (and if you have a proper charge in the system) unless you are monitoring both high and low pressures.
There is always a gamble if you are using a gauge on the can with nothing to monitor the high side pressure. Are you OK in most cases? Yes, but it's easy to avoid the gamble and monitor both.

 

The air blend door actuator is out of sync, meaning it's dying a slow death. Remove the negative battery connection for five minutes are reinstall. Sometimes it works, sometimes you simply have to replace it. I agree with the other comments, without verifying system pressure, system charge level, and a bi-directional scanner to check codes and the actuators, blower motor, resister or module, it's all words. The A/C system wants 0.454 Kg(1.0Lb) of R134a, no more, no less. You can't hit that mark blindly adding freon from a can into a system with an unknown quantity to start with.

 

Thanks Bob, It worked out perfectly, charged and worked fine till about a month ago. There must be a slow leak therefore added a green dye with a stop leak and recharged the system.

AC worked but only out of the passenger side, feels like outside air blowing out of the drivers side, The odd thing here is over the winter I was mentioning hot air came out of the driver side ducts but only warm air out of the passenger side which I was unable to find the problem. Came to the common conclusion that the heater core could be partially blocked. I googled and watched a video of a shop replacing the core and it wasn't something I was getting into for obvious reasons. I can live with it, wife's not too happy.

I must have a door issues regarding the AC and before I tear the car apart I need to identify the location of the blend door, which I don't have a knob to control. From what I've seen this knob would the in the center where mine is just the temp setting. AllenC above sent a link of a heater box that doesn't match mine. All the hvac controls operate correctly and do what there suppose to, directing the air to the correct ducts, temp adjustment and fan speed, this door must be doing it's own thing.

Would really appreciate any suggestions, thank you.

 

The green dye shows up really well when you use a blue light. They sell blue flashlights.

FWIW, the most likely problem on an older car is the evaporator, if you can't find evidence of a leak anywhere else and the compressor has stopped going on (the car will not run the compressor if there is insufficient refrigerant).