Car A/C Not Working

[s0me0nesmind1]

So for a while now my Car AC has gone to complete crap. I didn't notice it during the winter because it was just blowing the cold air from outside I assume.

Now in the summer, I notice that when I initially turn on my car it blows... at roughly 1/4 of what I expect. SORT of cool feeling initially. This is likely from the car itself being sort of cool since it's parked in the garage and not hot in general though I would think?



Things that it can be (to my knowledge)
1. Freon leaking
2. A/C Compressor Not working
3. A/C Filtration blocking
4. Fans not working on condenser

Freon Leaking: So I'll start with those. I checked the freon with an AC Gauge at an auto service place. Normal levels. So it's not a leaking that is the problem.

A/C Compressor: I run the car and I can see that the compressor is spinning, so from my knowledge, it's at least active? Not sure how to further diagnose this one

A/C Filtration: Took out the A/C Filter, it's practically brand new, so that's not the issue. Also tried running it without the Filter just incase...

Condenser Fans: Ran the car, and the radiator fans are working fine.


So what does this leave me? To my knowledge, the only thing left that I can think of is stuff that isn't under the hood, but rather behind the dash... That means Evaporator coils area.

Am I wrong there? Anyone else an expert in this area?

 

[BonzaiDuck]

Off the top of my head, it occurs to me that A/C systems -- at least of '90s vehicles like mine (and I don't see how this doesn't persist into "modern" times) -- have a thermal sensor which functions to control the operation of the compressor. I could be wrong. Answering your final line and question -- "I'm no expert in this area . . . "

I left it to my mechanic's repair-shop to assure my A/C was functioning and properly charged -- for the longest time. Then, fan-belts would squeal when I'd take it in for service, and asked them to fix it. They didn't. They insisted that the tension on the belt was "just so" and nothing wrong.

I finally determined myself that there was a tensioner on the A/C fan-belt that any owner with a 12mm socket with ratchet could adjust. Not much later, I found that the A/C had been overcharged with R132 refrigerant -- for the longest time. This caused it to be suboptimal in performance, leading me to think it was undercharged. The A/C and all its components (evaporator, condenser, compressor etc.) are all as old as the vehicle at 190,000 miles. Now -- everything about the A/C works as if it were brand-new.

Do you have the factory shop manual? there should be a trouble-shooting guide and an indication of the particulars like the thermal sensor that I mentioned.

Also, in the event something has actually gone wrong with the compressor -- they have a "clutch" assembly, for instance -- they're not all that expensive. If you don't work on your car yourself, of course, anything like this can be a pain in the ass and you might not want to pursue it by any other means than to take it to a mechanic and have it fixed.

 

[NutBucket]

#1 & #2 don't make sense. You can't check the levels without running the system. With the compressor running you'll read both high and low side pressure. then you can start figuring out what happened. The most common culprit is definitely low charge.

 

[s0me0nesmind1]

#1 & #2 don't make sense. You can't check the levels without running the system. With the compressor running you'll read both high and low side pressure. then you can start figuring out what happened. The most common culprit is definitely low charge.

#1 - 4 are just items that I've gone through of "things that there can be a problem with" - and then I wrote down how I checked them and don't believe there is a problem with them.

I mentioned going to a mechanic and he used AC Gauges (both high + low inputs) and said they were normal levels... Yes, this was with the car running.

This particular mechanic wasn't an expert in AC though, so he recommended me another place to go - which I haven't gone to yet because of the pandemic.


So lately I've just been trying to see if I can self-diagnose it to determine what the problem is. To be honest, this is for my 2006 Acura TSX... If it's something that is going to be expensive to repair such as over $1,000 then it just won't be worth it to me at this point.

 

[BonzaiDuck]

#1 - 4 are just items that I've gone through of "things that there can be a problem with" - and then I wrote down how I checked them and don't believe there is a problem with them.

I mentioned going to a mechanic and he used AC Gauges (both high + low inputs) and said they were normal levels... Yes, this was with the car running.

This particular mechanic wasn't an expert in AC though, so he recommended me another place to go - which I haven't gone to yet because of the pandemic.


So lately I've just been trying to see if I can self-diagnose it to determine what the problem is. To be honest, this is for my 2006 Acura TSX... If it's something that is going to be expensive to repair such as over $1,000 then it just won't be worth it to me at this point.

Well, there's an expected expense for troubleshooting -- "Cost of finding the cause of the problem".
Then, there's an expected expense for expensive parts. Would it be the Compressor? The Condenser? The Evaporator? Or a temperature sensor?

Poke around at RockAuto for your car and expand the "Heat and Air Conditioning" section. A compressor, for instance, would be at most $199, but RockAuto offers less expensive alternatives in the list.

Then, figure the cost of labor. You could make up a list of several items, and ask a mechanic, or get an estimate online from any of a handful of "Mechanic-Help" sites.

But the first thing to do is the troubleshooting.

Also, just a reminder and thinking of another poster's remark: poor cooling performance can be caused by two things in the nature of refrigerant charge. Undercharging -- it goes without saying. Overcharging -- almost counterintuitive, but the physics of it makes sense.

How many more miles do you WANT to get from this Acura? Did you buy it new? What have your annual average repair-and-maintenance bills been? Putting $1,000 into a car with good expectations of another 60,000 miles is not unreasonable, if keeping the car is desirable to you. Hopefully, you wouldn't spend more than normal for oil changes and diagnostics for the next couple years. But even $1,000 in a year's time is a lot less than a new-car mortgage, and certainly less than the annual insurance bill, even without "full comprehensive".

 

[boomerang]

Now in the summer, I notice that when I initially turn on my car it blows... at roughly 1/4 of what I expect. SORT of cool feeling initially

This can be interpreted several ways and I am uncertain what exactly you mean. Are you saying that the airflow is lower than you feel it should be or are you saying that the temperature of the air is not as cool as you expect it to be?

Assuming that the temperature output is too high, you may have a problem with the blend door actuator which is causing heated air to be mixed in with the cooled air. The part is cheap but how difficult it is to get to, I don't know.

Your car also has a heater valve which more than likely will cut off coolant flow to the heater core within the car. If that is hanging open or only partially closing, it could be contributing to the problem. Again, I'm assuming that the issue is temperature of the discharge air, not air flow. The valve should be under the hood and essentially spliced into a heater hose or pipe. You should be able to see it open and close with a friend moving the temperature control from full heat to full cool.

 

[s0me0nesmind1]

This can be interpreted several ways and I am uncertain what exactly you mean. Are you saying that the airflow is lower than you feel it should be or are you saying that the temperature of the air is not as cool as you expect it to be?

Assuming that the temperature output is too high, you may have a problem with the blend door actuator which is causing heated air to be mixed in with the cooled air. The part is cheap but how difficult it is to get to, I don't know.

Your car also has a heater valve which more than likely will cut off coolant flow to the heater core within the car. If that is hanging open or only partially closing, it could be contributing to the problem. Again, I'm assuming that the issue is temperature of the discharge air, not air flow. The valve should be under the hood and essentially spliced into a heater hose or pipe. You should be able to see it open and close with a friend moving the temperature control from full heat to full cool.

I mean that the airflow is consistent (if I switch airflow to high - it goes high, etc.). The temperature is what I mean that is significantly warm.

I thought of the blend door as well, but I believe I squashed that one? I have temperature control for each side (driver/passenger), and I can switch either side to heater and it indeed does come out with heat and the opposite side will stay at the "not cold" AC.

 

[boomerang]

I mean that the airflow is consistent (if I switch airflow to high - it goes high, etc.). The temperature is what I mean that is significantly warm.

I thought of the blend door as well, but I believe I squashed that one? I have temperature control for each side (driver/passenger), and I can switch either side to heater and it indeed does come out with heat and the opposite side will stay at the "not cold" AC.

I would look to see whether the arm is moving on that heater valve. If it's not moving electrically, (it might be operated by a cable, I don't know) maybe you can move it manually and see if that makes a difference. The part is like $15 at rockauto so the fix could be very inexpensive.

 

[s0me0nesmind1]

Well, there's an expected expense for troubleshooting -- "Cost of finding the cause of the problem".
Then, there's an expected expense for expensive parts. Would it be the Compressor? The Condenser? The Evaporator? Or a temperature sensor?

Poke around at RockAuto for your car and expand the "Heat and Air Conditioning" section. A compressor, for instance, would be at most $199, but RockAuto offers less expensive alternatives in the list.

Then, figure the cost of labor. You could make up a list of several items, and ask a mechanic, or get an estimate online from any of a handful of "Mechanic-Help" sites.

But the first thing to do is the troubleshooting.

Also, just a reminder and thinking of another poster's remark: poor cooling performance can be caused by two things in the nature of refrigerant charge. Undercharging -- it goes without saying. Overcharging -- almost counterintuitive, but the physics of it makes sense.

How many more miles do you WANT to get from this Acura? Did you buy it new? What have your annual average repair-and-maintenance bills been? Putting $1,000 into a car with good expectations of another 60,000 miles is not unreasonable, if keeping the car is desirable to you. Hopefully, you wouldn't spend more than normal for oil changes and diagnostics for the next couple years. But even $1,000 in a year's time is a lot less than a new-car mortgage, and certainly less than the annual insurance bill, even without "full comprehensive".

Truedat'

Car is (as said in post above) Acura TSX 2006. Mileage is roughly... 130 or 140k.

Things I've replaced:
Power Steering Pump
Starter
Spark Plugs
Serpentine Belt
Radiator (latest - due to me rear-ending someone else, long story)

First step I agree is diagnosing the problem. I was hoping to be able to do it myself, but I'm guessing I'm going to need to go to an expert and just pay them < $100 to tell me whats wrong. I'm willing to go for that once this COVID-19 shit clears.

My problem is simply that if it is over $800 or so to fix it, I honestly don't think it will be worth it in the end?

As far as undercharging/overcharging, I don't see how that can be the case. I haven't touched the coolant stuff in the ENTIRE time I've owned the car.




As far as how many miles I want to get out of the car... I would love for it to be 200k+ The problem is the more and more that I go on the more and more I get a... feeling of uncertainty... where I start to lack confidence and feel like I could be on a 4-hour road-trip to another city for work and have a breakdown. Maybe I'm just being irrational though, the car is starting to make more noises in general, but as far as I can tell the AC is the only thing wrong with it right now. I've also plugged it in and it doesn't report any fault codes.

 

[boomerang]

As far as undercharging/overcharging, I don't see how that can be the case. I haven't touched the coolant stuff in the ENTIRE time I've owned the car.

Now we're getting somewhere. In front of the radiator is the condenser for the AC system. If you had to have the radiator replaced do to a minor accident, I don't see how the condenser survived undamaged. Your symptoms are typical of a low refrigerant level.

You have a minor leak. The leak must be repaired, the system must be evacuated (put on a vacuum pump) and then recharged.

 

[s0me0nesmind1]

Now we're getting somewhere. In front of the radiator is the condenser for the AC system. If you had to have the radiator replaced do to a minor accident, I don't see how the condenser survived undamaged. Your symptoms are typical of a low refrigerant level.

You have a minor leak. The leak must be repaired, the system must be evacuated (put on a vacuum pump) and then recharged.

Like I said, I had a mechanic guy put A/C gauges on it and the pressure amounts seemed normal.

If it was just a minor leak, I also wouldn't expect for it to be blowing completely warm air and more along the lines of "mediocre" cold.

 

[snoopy7548]

I had an '07 Versa that, a couple of summers ago (when it was around 10 years old), started blowing warm air when I had the AC on. Before that, it was perfectly fine.

I spent days ripping apart the dash, checking the blend door, everything. I finally said "F it", bought one of those AC recharge cans with the gauge, recharged the AC, and until I got rid of the car (last October) the AC worked just like new.

I'd try that. Worst-case, you're out $25 for the cost of the can. People say the AC is a fully-closed system, but it can and will lose freon over time, especially if it's an older car. Connections get weak, hoses crack.

After you recharge, see if your AC starts blowing warm air again. If it does, you know you have a leak that needs to be addressed. If not, you're probably good to go.

This guy on YouTube is awesome:

 

[s0me0nesmind1]

I had an '07 Versa that, a couple of summers ago (when it was around 10 years old), started blowing warm air when I had the AC on. Before that, it was perfectly fine.

I spent days ripping apart the dash, checking the blend door, everything. I finally said "F it", bought one of those AC recharge cans with the gauge, recharged the AC, and until I got rid of the car (last October) the AC worked just like new.

I'd try that. Worst-case, you're out $25 for the cost of the can. People say the AC is a fully-closed system, but it can and will lose freon over time, especially if it's an older car. Connections get weak, hoses crack.

That's exactly what I was hoping it was - to the point where I ordered one of those recharge kits from Amazon (and subsequently cancelled it after thinking about it).

My only problem is (as some above alluded to) that overcharging the AC (if it isn't actually leaking) can seriously fuck things up worse

That's why I took it to a guy to check it with gauges first... turns out it's still full =/

 

[snoopy7548]

That's exactly what I was hoping it was - to the point where I ordered one of those recharge kits from Amazon (and subsequently cancelled it after thinking about it).

My only problem is (as some above alluded to) that overcharging the AC (if it isn't actually leaking) can seriously fuck things up worse

That's why I took it to a guy to check it with gauges first... turns out it's still full =/

As long as you adjust the gauge correctly (according to the outside temp) and follow the directions, you won't overcharge it.

There are many factors involved when checking refrigerant levels. You said the mechanic wasn't an expert in AC; it's likely he didn't really know what he was doing, didn't adjust his gauges properly, and just wants to sell you on an expensive repair.

 

[BonzaiDuck]

Truedat'

Car is (as said in post above) Acura TSX 2006. Mileage is roughly... 130 or 140k.

Things I've replaced:
Power Steering Pump
Starter
Spark Plugs
Serpentine Belt
Radiator (latest - due to me rear-ending someone else, long story)

First step I agree is diagnosing the problem. I was hoping to be able to do it myself, but I'm guessing I'm going to need to go to an expert and just pay them < $100 to tell me whats wrong. I'm willing to go for that once this COVID-19 shit clears.

My problem is simply that if it is over $800 or so to fix it, I honestly don't think it will be worth it in the end?

As far as undercharging/overcharging, I don't see how that can be the case. I haven't touched the coolant stuff in the ENTIRE time I've owned the car.




As far as how many miles I want to get out of the car... I would love for it to be 200k+ The problem is the more and more that I go on the more and more I get a... feeling of uncertainty... where I start to lack confidence and feel like I could be on a 4-hour road-trip to another city for work and have a breakdown. Maybe I'm just being irrational though, the car is starting to make more noises in general, but as far as I can tell the AC is the only thing wrong with it right now. I've also plugged it in and it doesn't report any fault codes.

Ummm . . . lemme open another tab and take a look at that Acura . . . Yeah. I found a You-Tube driving-down-the-road review of your car.

This "feeling of uncertainty" accompanies the used or aging "car experience". People who habitually buy new cars wouldn't have a clue. For someone who bought a new or even pre-owned car, it sort of creeps up on you. I'd suggest creating a spreadsheet and entering all the repairs and service done, if you keep the paper records or digital facsimiles.

Do you have the shop manual? Not the owner's manual -- but the factory shop manual. I'd get it, and preferably -- find a source where you can download (and even pay for!) a searchable-PDF version. After that, look at basic "subsystems". How many miles since last significant engine-work? How long since the transmission was flushed? When did you replace --say -- an alternator? You already know about those things you've listed. In both owner's and shop manual, there should be a chronological block diagram or something similar that extends to 100,000 miles. Look to see what sorts of service has been ignored, and make arrangements -- a plan -- to do things like replacing the differential gear oil, or repacking the wheel bearings. How much oil does it burn, and how much does it leak? Things like that. IF the engine is in good shape, then it's a "good car".

It's harder for me to give more specific advice about this. I've got my SUV to a point where I simply cannot imagine anything going wrong with it for at least another 50,000 miles.

I spend a lot of time "managing" my 25-year-old SUV, and a lot of people don't have a lot of time. Of course, if you do some of these things, all the info-management stuff has been done up front. You have a better idea how much you MAY need to spend annually and in the future. You can PLAN to do things beyond ordinary oil-change and routine maintenance, and schedule them for the following year or thereafter.

The other thing I'd suggest is to make a habit of tracing down those "noises" you speak of. As analog, I made a project of determining the cause of all my oil leaks -- both 10W-30 and Dexron-III. I was able to stifle them, mostly without repair-shop assistance, and even then -- I TOLD them what to do -- they didn't "suggest" them to me. Now, for instance, I have "squeaking" noises, and I know from my shop manual schedule that body points and may suspension parts need some attention with a grease-gun, so I'll tell my mechanic to do that in September, because he's the one who has the hydraulic lift, and for something like that -- I won't want to fiddle with jack-stands.

Personally, I'd say it's a nice car. I've had a number of Hondas, and always -- at that time -- lusted after the newer Acuras. The reviewer noted that it wasn't a "performance" ride, but he was all positive about it. I was impressed. I would've wanted a car like that 20 years ago. Now -- I like the feeling of "being on safari" with every trip to the grocery store, able to leap road obstructions with a single pedal-surge. To me, it's a "sweet ride". And -- it's "roomy". I lost the desire to feel like I'm in a space capsule -- "rocket man! Burnin' out the fuse of every-one-e-e-!"

 

[boomerang]

Like I said, I had a mechanic guy put A/C gauges on it and the pressure amounts seemed normal.

If it was just a minor leak, I also wouldn't expect for it to be blowing completely warm air and more along the lines of "mediocre" cold.

And he said that he was not an expert and that you should take it to someone else.

I've led you to the water, it's your choice whether to drink. Best of luck.

 

[BonzaiDuck]

Just my opinion, but he has some affection for the car, and I don't think his worries about the worst-case repair expense for the A/C is either a significant decision factor, or even warranted for the "worst-case".

Sometimes, a shortcoming like this for an automobile will loom and grow large in the owner's mind, like the housefly turning into Godzilla for Carlos Castaneda in "Tales of Power" or some other book about Mexican Brujos and LSD Mescaline experiences. I say -- put it in perspective and have it fixed. If it's hemorrhaging and burning oil and failing smog-test, that's something else. You have to really have sexual love for a vehicle these days to replace or overhaul an engine.

 

[Paperdoc]

Checking the compressor operation can be tricky, especially the clutch on the compressor. This is how it operates. The compressor is NOT supposed to operate all the time - it is turned on and off via a sensor and clutch. The pulley on the end of the compressor is driven by a belt. Hidden behind the pulley is a small clutch operated by an electrical solenoid, and there's a wire to that solenoid connected to a controller. Inside your heater body there is a small temperature sensor next to the evaporator coil. The overall system design is such that continuous operation of the compressor can cool the evap coil so low it gets to freezing cold and builds up frost, which plugs up the air passages and stops if from working. The sensor feeds that evap coil temp to a controller that shuts off the compressor when it gets just a couple degrees above freezing to prevent this, then turns it back on when the temp rises. Turning the compressor on and off is done by the clutch behind the pulley - it pulls in a plunger that connects the pulley to the compressor drive shaft to make it turn. So the NORMAL operation is that the compressor clutch constantly pulls in and releases (typically, a few minutes between changes) to keep the evap coil temperature cold but not frozen.

To observe this you need the system running fully with engine running, and you need to be able to see the pulley end of the compressor. On many such systems, the central hub in the pulley is actually the end of the clutch plunger, and it moves only a small amount in and out. BUT when it is pulled in to engage, it turns, and when it releases it stops turning. So watch that hub and see whether it is starting and stopping. If it never turns, then the clutch is never pulling in, and there is likely a problem with the sensor, the wiring, the clutch mechanicals, or the clutch solenoid. If it never stops, the problem could be any of those, or possibly some blockage in the refrigerant system that prevents refrigerant flow so that there is never enough cooling in the evap coil to get it down to near-freezing.

A good A/C shop can test the system thoroughly. Testing and diagnosis might cost you a couple hundred, but then you'll know exactly what needs fixing, and get an estimate. Tell them NOT to fix anything without your instructions - just diagnose. When my mechanic did this, typically with the engine running he would connect hoses and use a vacuum pump to suck out all the refrigerant, watching the pressure gauge. Then he'd turn valves to isolate the system and watch pressure again over 15 minute or more. How fast it could be pumped down, how low the vacuum pressure got to, and how long it would stay down without the vacuum pump pulling, all tell him a lot.

One thing that might have happened is that, with a small leak in the system, some water vapour from the air got in. The system has some moisture-absorbing pellets in a bag in the receiver reservoir to scavenge any such moisture, but if too much accumulates over time it cannot handle all of it, and actual water drops form and move around in the system. When they get to the cold evap coil, they can freeze there and block up the refrigerant flow. Then when you shut down, they slowly melt and temporarily free up the system. Leaving the entire system under a vaccum for several hours will evaprate all the accumulated water vapour in the system and from those pellets, restoring the dry conditions needed for re-charging. Ask about this, too, if you get such work done. When they are finished and refill the refrigerant system, have them add some leak-tracer dye to it. This is a chemical that glows under ultraviolet light. When that is in your system and you use it normally, some refrigerant will leak out of any small leak point and carry with it the dye. So after a week or two the mechanic can go under the hood with a UV lamp and look for bright yellow-green stains from the dye, to find any undetected leak points.

 

[trenchfoot]

Blocked/partially blocked expansion valve and orifice tube may be your problem as I've not seen it mentioned yet in this thread. I haven't looked into the possibility that that may be the cause however I'll check it out with a couple of my mechanic friends and see what they say about that or others in this forum may have experience with this particular issue.

Whenever I do an A/C system flush/overhaul I swap out those two parts as a matter of course because they're pretty cheap and worth the peace of mind IMO.

 

[NutBucket]

Cheap? The expansion valve for my Subaru was $100! But it has to be my problem since the low side pressure is REALLY low while high side is normal. Maybe now with this lockdown I'll get around to fixing it before summer.

 

[s0me0nesmind1]

bump...

Finally took my car in today to find out what the actual culprit was...

It was a leak lol.

A/C Discharge hose was apparently having a slight small leak.


Talked to the guy about it - and he said in general... Yeah you can't really tell with gauges, thats why the way they do is having a machine that sucks out the freon, measures it - compares it to what it should be - and then figures it out that way instead of trying to go by pressure.

Overall cost me ~$420 repair which was within reason for me to pay I suppose. A/C Discharge hose for the part alone was $185.

 

[jlee]

bump...

Finally took my car in today to find out what the actual culprit was...

It was a leak lol.

A/C Discharge hose was apparently having a slight small leak.


Talked to the guy about it - and he said in general... Yeah you can't really tell with gauges, thats why the way they do is having a machine that sucks out the freon, measures it - compares it to what it should be - and then figures it out that way instead of trying to go by pressure.

Overall cost me ~$420 repair which was within reason for me to pay I suppose. A/C Discharge hose for the part alone was $185.

Glad you got it sorted. Mechanic #2 is correct - AC systems have a specification (by weight) for refrigerant capacity. You can WAG your way into a working system by filling until you're seeing the pressures you expect, but it's not ideal.

 

[Paperdoc]

Even weighing the coolant removed and comparing to specs will really only tell you yes, there is some missing. One presumes a leak, then. But finding it can be tough if it is small, or in a place hard to get close. My wife's car had a similar problem - leak in a combined metal and rubber hose from compresor discharge to Conderner in front of the rad. My tech knew there was a leak but could not find it when the system was fully charged, and he HAD added the leak tracer dye. Told me to keep a close eye for poor cooling and come back - might take a week. It did show poorer cooling in less than a week, so went back. With his UV light he found the leak right away. I bought the part, he installed, and it was just fine after that.

I nay go through a similar process this coming week. My daughter's car (over 10 years old) appears to have failed A/C for the first time in its life.

 

[NutBucket]

Glad you got it sorted. Mechanic #2 is correct - AC systems have a specification (by weight) for refrigerant capacity. You can WAG your way into a working system by filling until you're seeing the pressures you expect, but it's not ideal.

I will agree that you only know how much refrigerant you have buy evacuating it but there are lots of other issues that measuring pressure can help you troubleshoot:

https://www.sanden.com/objects/SANDEN_SYSTEM_DIAGNOSIS_CHART.pdf

 

[NutBucket]

Update. Went to a friend's shop with the intent of just evacuating the system. I was about 6oz low on R134 so I decided to just pull a vacuum and see what happened. I let it hold vacuum for about 20 minutes and refilled it. Everything seems fine and it's now as cold as it ever was (which is to say adequate at best). One of my pet peeves about older Japanese cars....undersized AC!