AC help

[fblainen11]

A couple of weeks ago my wife's AC stopped cooling in our 00.
I brought it in to a knowledgable/reputable AC specialist in town who I've had do work for me before. Honest guy.

I was low on freon so he put some dye in and filled it and said to bring it back when it stopped cooling. After one week it stopped. He looked and found two leaks. $500 later I have a couple new lines and a new condensor. (I think that's what he replaced. I'll check my invoice). I have a 1 year warranty.

So now my wife tells me it will only cool for the first 5-10 minutes but then it can't stay cool. Especially when the car is not moving. She brought it back to the guy and he checked to make sure it had freon. Freon levels were fine. He told her to keep it off of the recirculate because it will freeze up.

My 01 can run full blast at a stand still and stay pretty freaking cold in 98 degree south Louisiana heat/humidity.

What else could be wrong? I don't think after $500 that the new part he just put in should be freezing up.
Any input?

 

[FrenchToasty]

It's probably low again and they are waiting for the comp/clutch to go from short cycling on the LP switch. More money in their pocket. Look for oil/dirt residue around the comp, hi side going to condenser and from condenser to evap, also look around the schraider valves.

 

[mtbtim]

I'm just starting to learn about AC and us DIY mechanics would need to know more information, mainly what are the pressures on the low and high side. Without that information, it would be hard to diagnose a problem effectively. To know that information, you need a manifold gauge set. With the low and high side numbers and some more information of the symptoms the system is presenting, you can narrow down what is causing the problem.

For a $500 repair bill, I'd take it back to this mechanic and tell him you're not happy that it's still not working right. I'm also having a hard time believing you had 3 different leaks at the same time. If he's going to charge you more to diagnose the problem further, I'd take it to someone else. He might seem honest but a good mechanic wouldn't be happy with that kind of shotty work and would try to figure out the cause of the problem at no additional labor cost.

 

[Boudin]

Who did you take it to? I'm also from Denham Springs. I think my Thermistor is bad causing it to cycle on and off too soon. I'm wondering if your having the same issue.

Are you hearing a clicking by the glove box frequently?

It sounds like it may be overcharged, causing the high pressure safety switch to trigger and cutting off the compressor.


Sent from my SM-G930V using Tapatalk

 

[LittleCaesar]

If the low pressure line is real wet/cold, or the evaporator is cold and/or the low pressure side is extremely low then you may have a bad expansion valve.

I take it the fan clutch is original?

 

[drg007]

Is better to replace receiver dryer (A/C filter) also, when they replaced the leaking freon lines.

 

[stir_fry_boy]

You probably have an additional leak somewhere that the mechanic missed. It's easy to miss a small pinhole leak. I wouldn't run the A/C until you get it completely charged up, as the A/C compressor depends on the freon level to cool itself. If it's not cooling inside the truck, chances are the compressor is at risk from overheating because you are at that fine line between when the system says it's ok to have the compressor on due to minimum pressure, and lack of a full charge. I would take it back to whomever did the work honestly.

Changing the drier will only help if the lines were undone for more than a couple of hours, depending on the humidity outside. If he had the lines undone for some time, ask to change the drier. At Toyota they run about $30 and aftermarket are around $10.

The system will also not cool well if there is no air movement across the condenser. Make sure your fan is working properly as [MENTION=69868]LittleCaesar[/MENTION] suggested.

If you are low on a charge, and you don't have good air moving across the condenser, or a stuck expansion valve, it will definitely cause your issue. Just because you don't have good air movement across the condenser isn't enough to make the A/C completely stop cooling.

Bad expansion valves are rare on these trucks, but they can happen.

 

[fblainen11]

Im no longer in Denham Springs. I live near lake Charles now.

The pressures are fine. When we took it back he put the gauges on it and said it wasn't leaking. The guy has been in business for a long time and is reputable. He's done work for me before and I know the other mechanic there as well. They're standup people and I know the mechanic isn't the issue.

He didn't have time to keep looking at it, he went on vacation.

It does drip a lot of water when it is running. Much more so that my 01.

I also know it's not low on freon because it will cool when the vehicle first turns on for about 5 minutes. Then it goes out.

If it were low and leaking it would eventually stop running.

There were three different leaks because two were a hose that was leaking from the connections on each end. The 3rd leak was whatever the part is that's near the dash on the passenger side.

 

[mtbtim]

It would be helpful to know what the pressures are doing when the AC is working within those 5 minutes and then what happens to the pressure when the AC stops blowing cold.

With only the information you've provided so far, periodic AC function could point to an expansion valve problem which was already stated as a possibility.

I'm guessing the mechanic must have pulled a vacuum after replacing those parts to evacuate any air and moisture. The receiver/dryer could be the issue as well. If it's not doing the job taking moisture out before sending the freon to the expansion valve, that moisture could freeze at the expansion valve causing a blockage.

 

[JRZEE2000TR4LTD]

If there is condensate dripping from the truck then it almost has to be working. With the AC on is one of the 2 lines pretty cold going into the cabin? Should be sweating. Your compressor should be cycling on for about 1 minute or so and off for about 30 seconds on an 80-85 degree day. If your system was "freezing up" the compressor probably wouldn't cycle. Also, you would probably see "fog" coming from your vents before it actually froze. I might be looking more at one of your air AC/heater box servos or the doors themselves. Maybe as the truck heats up it is "warming" the cooled air. Also look at the heater valve on the firewall.

 

[nissanh]

AC is a simple system. When all those simple items work together, you get a fully functional AC. Most mechanics working with AC systems has no idea how it works. They simply replace every component until cold air comes out from the vent.

Do you have digital climate control or mechanical? If mechanical, it is very straightforward to diagnose the issue.

How fast the blower is running? Do you have the blend door set to cold (blue) zone? Sometimes, when the blower is running slow, the "thing" (evaporator) inside the dash on passenger side freezes and clogs the air flow, hence no cold air from the vents.

 

[stir_fry_boy]

Im no longer in Denham Springs. I live near lake Charles now.

The pressures are fine. When we took it back he put the gauges on it and said it wasn't leaking. The guy has been in business for a long time and is reputable. He's done work for me before and I know the other mechanic there as well. They're standup people and I know the mechanic isn't the issue.

He didn't have time to keep looking at it, he went on vacation.

It does drip a lot of water when it is running. Much more so that my 01.

I also know it's not low on freon because it will cool when the vehicle first turns on for about 5 minutes. Then it goes out.

If it were low and leaking it would eventually stop running.

There were three different leaks because two were a hose that was leaking from the connections on each end. The 3rd leak was whatever the part is that's near the dash on the passenger side.

I agree that the heater controls need to be checked, and you need to know what the system is doing with the manifold gauges attached. Seems like the system could be working if you are getting that much condensation on the ground which is most likely from the evaporator core.

This will be interesting to see what is the diagnosis.

 

[JRZEE2000TR4LTD]

Here's all the things that would cause freezing

1. Moisture within the AC system causing ice an plugging the expansion (any debris in the system can block the expansion valve) valve causing the low side pressure to go too low and turn the evaporator into a block of ice. You would notice deceased air flow and cold fog coming out of the vents.

2. Possibly a blocked evaporator drain although the evaporator should never get cold enough to freeze the blocked water.

3. Faulty pressure switch (which on our trucks is on the hi side , liquid line, going into the evaporator) causing the compressor to not cycle and run the low side pressure too low causing the evaporator to freeze.

4. Low refrigerant level causing low side pressure and freezing the evaporator.

If you haven't noticed, the theme here is low side pressure being too low. Refrigerant pressure and temperature are linear to one another. For 134A refrigerant, if the low side pressure gets below 25-28 psi, 134A is just about at 32 degrees, causing freezing. So essentially any blockage in the system, whether it be in the receiver drier, expansion valve, etc, which would cause low side pressure to go too low, would cause freezing.
At this point, as other have stated, we really need to know the high and low side pressures. I still don't think it's in the AC system because you said water is dripping out, but since it was just worked on, we need to be sure that the proper diagnosis was attained. Weird your mechanic told you to keep it off recirculate. That may stop freezing as it allowing outside warm air to move through the evaporator, but there is still a problem obviously. I assume he told you that for a temporary fix until he can look at it further. I also hope he replaced the receiver drier. It's cheap and easy enough to replace.

 

[fblainen11]

Here's all the things that would cause freezing

1. Moisture within the AC system causing ice an plugging the expansion (any debris in the system can block the expansion valve) valve causing the low side pressure to go too low and turn the evaporator into a block of ice. You would notice deceased air flow and cold fog coming out of the vents.

2. Possibly a blocked evaporator drain although the evaporator should never get cold enough to freeze the blocked water.

3. Faulty pressure switch (which on our trucks is on the hi side , liquid line, going into the evaporator) causing the compressor to not cycle and run the low side pressure too low causing the evaporator to freeze.

4. Low refrigerant level causing low side pressure and freezing the evaporator.

If you haven't noticed, the theme here is low side pressure being too low. Refrigerant pressure and temperature are linear to one another. For 134A refrigerant, if the low side pressure gets below 25-28 psi, 134A is just about at 32 degrees, causing freezing. So essentially any blockage in the system, whether it be in the receiver drier, expansion valve, etc, which would cause low side pressure to go too low, would cause freezing.
At this point, as other have stated, we really need to know the high and low side pressures. I still don't think it's in the AC system because you said water is dripping out, but since it was just worked on, we need to be sure that the proper diagnosis was attained. Weird your mechanic told you to keep it off recirculate. That may stop freezing as it allowing outside warm air to move through the evaporator, but there is still a problem obviously. I assume he told you that for a temporary fix until he can look at it further. I also hope he replaced the receiver drier. It's cheap and easy enough to replace.

Thanks for the tips. At this point I'm just going to wait for him to get back and then bring it in again.

 

[LittleCaesar]

If you do have to open the system back up again, replace the drier. It is a $22 Denso part.

I take it everything in the slight glass looks OK? A Denso expansion is $30 on Ebay.

 

[StreetCreeper]

Thanks for the tips. At this point I'm just going to wait for him to get back and then bring it in again.

You mention that it works for the "first ten minutes". What does that mean? The first ten minutes when the truck is cold (meaning coolant temp is the same temp as the environment)? Or do you mean the first ten minutes every time you turn the a/c on?

If you never turn the a/c on all day yet drive the truck until the coolant temp read around 190~* and then you turn the a/c for the first time — does it work for ten minutes or no?

What I'm getting at is what Little Caesar mentioned and that's the fan clutch. If the clutch is not working properly, the a/c would probably blow cold when the engine is still cold since the engine coolant temp isn't inundating the fan clutch's ability to cool the condenser. But as soon as the truck warms up to operating temp, the faulty/inefficient fan clutch is overwhelmed by the additional heat from the engine and the a/c will start blowing warmer air.

Just something to consider.

Also, when testing the fan clutch using all the normal test, keep in mind that though it may pass the tests — it can still be failing as mine was.

 

[mtbtim]

You mention that it works for the "first ten minutes". What does that mean? The first ten minutes when the truck is cold (meaning coolant temp is the same temp as the environment)? Or do you mean the first ten minutes every time you turn the a/c on?

If you never turn the a/c on all day yet drive the truck until the coolant temp read around 190~* and then you turn the a/c for the first time — does it work for ten minutes or no?

What I'm getting at is what Little Caesar mentioned and that's the fan clutch. If the clutch is not working properly, the a/c would probably blow cold when the engine is still cold since the engine coolant temp isn't inundating the fan clutch's ability to cool the condenser. But as soon as the truck warms up to operating temp, the faulty/inefficient fan clutch is overwhelmed by the additional heat from the engine and the a/c will start blowing warmer air.

Just something to consider.

Also, when testing the fan clutch using all the normal test, keep in mind that though it may pass the tests — it can still be failing as mine was.

On that line of thinking, if the fan clutch were the culprit, you'd expect poor AC performance at a stop and then expect the AC to start working well again once you hit the highway and got good air flow through the condenser. Definitely something the OP could check out before bringing it back to the mechanic.

 

[StreetCreeper]

On that line of thinking, if the fan clutch were the culprit, you'd expect poor AC performance at a stop and then expect the AC to start working well again once you hit the highway and got good air flow through the condenser. Definitely something the OP could check out before bringing it back to the mechanic.

Yeah he briefly mentioned in his original post about it being worse when the truck isn't moving.

So now my wife tells me it will only cool for the first 5-10 minutes but then it can't stay cool. Especially when the car is not moving.

 

[mtbtim]

Yeah he briefly mentioned in his original post about it being worse when the truck isn't moving.

BUT, if the fan clutch is the culprit, he should also be experiencing high coolant temps as well. However, I'm guessing the OP neither has a scan gauge nor a OBDII bluetooth reader with a phone app to confirm what his coolant temps are.

 

[fblainen11]

BUT, if the fan clutch is the culprit, he should also be experiencing high coolant temps as well. However, I'm guessing the OP neither has a scan gauge nor a OBDII bluetooth reader with a phone app to confirm what his coolant temps are.

I have an OBD II wifi reader, not Bluetooth. What coolant temp should I be at?

Also, it works when the engine is cold at startup for about 10 minutes.
Even when driving 55-65 mph the AC will still not blow cold.

Edit: What's the best iPhone app for my reader? The one I have was free: EOBD-Facile.