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Air Conditioning Problem

30K views 25 replies 10 participants last post by  BlindWilly 
#1 ·
Hello Everyone,
I have a 2010 FJ with 108,000 km on it, which I purchased last year. It has seemed to be running great until this week, when I noticed that the air conditioning was not working so well. Specifically, it seems to fluctuate between working reasonably well and just blowing normal air. I have further noticed that it tends to work better when I am actually driving, as opposed to just idling or driving at slower speeds. I don't think that this is normal, as it is new. I could use any advice, as I can't afford expensive diagnostics right now; particularly if they don't show anything or the problem is intermittent. I have done a search and found a few similar problems, but none that are exactly the same or no specific answers. Thanks in advance for any help.
Brice
 
#2 ·
It sounds like you may be low on refrigerant...when driving your rpm is higher which will drive the compressor at a higher speed. You want to look around for any possible leak spots, they can show up as a wet dirty spot around fittings or if the a/c lines have been in contact with sharp edges ... one of the most common problem areas has been with the installation of a new front after market bumper. Start looking there if you do have a new bumper. It is not a great plan to just go grab a can of 134a and add to the system, The correct amount of charge is important and over charging can possibly cause other more expensive problems.
One other possible problem could be a dirt plugged condenser coil in front of the radiator but you would need to have been running in mud and water holes or driven thosands of miles on dirt roads. Always a good plan to wash the radiator area on a regular basis.
 
#6 ·
On the basis of the feedback here, I have started with cleaning the compressor coil and checking the a/c lines. I wasn't able to see any leaks or wet spots, but that may also be a function of my mechanical inexperience. I had been doing some off-roading a couple of weeks ago in some pretty serious mud, so was hoping that cleaning things might help. I found that, after cleaning of the compressor coils a couple of times, the performance improved significantly, although not totally. The air conditioning is working at about 70-80% now, I'd guess, but I have cleaned the compressor about three times. So I'm not sure about next steps in terms of what to do given these findings. Any further recommendations?
Thanks again,
Brice
 
#7 ·
Six critical points:

A. There must be adequate airflow through the condenser;
B. There must be adequate airflow through the evaporator;
C. The compressor must be driven at the correct speed with no belt or clutch slippage;
D. The system must have the correct volume of refrigerant (verified by checking high-side & low-side pressures while compressor is operating).
E. The compressor control system must properly sense the temperature at the evaporator & compressor control electronics must properly actuate compressor clutch.
F. Blend door in HVAC ducting must operate properly (direct air either through heater core, or through evaporator core).

Simple checks first:
1. Verify that BOTH the engine radiator and the AC condenser are free of dried mud or other blockage. Check by holding a flashlight behind the radiator at night, while looking into the condenser.

2. It's difficult to verify that the evaporator is free of debris because its buried under the dash. Since this is a previously-owned vehicle with unknown prior history, previous owned could have operated without HVAC filter in place. For the moment, assume that the evaporator is not blocked.

3. Verify that the compressor drive belt is the correct length, and properly routed around the pulleys (belt in FJ CAN be misrouted, but still appear to drive pulleys). Check that the belt is in good condition and not glazed or oily. Verify that the compressor clutch is not oil-soaked. Verify that the compressor clutch engages when the AC is turned on, and that it STAYS ENGAGED.

4. If these preliminary checks look good, the single most important test is to verify that the high-side and low-side refrigerant pressures are correct. You'll need a refrigerant gage manifold for R134A refrigerant (each type of refrigerant has its own unique connectors). Connect the gage set to the test ports on the AC lines, and run the engine at ~1500 RPM for at least 5 minutes, then carefully check pressures while engine is held at 1500 RPM. Low side should be around 20-35 PSI, high side around 200-230 PSI.

Let us know what you find ...
 
#8 ·
Hello Everyone,
Thanks so much for the advice so far. I have only been able to follow through on some of it due to my limited vehicle knowledge and equipment.

I have changed the air cabin filter, washed the compressor coils and radiator, checked the compressor drive belt, and checked that A/C lines and fittings. This appears to have resulted in general improvement.

I have been unable to check the refrigerant pressures because I am unsure of how to do this and don't have the required gauge. I haven't been able to see if the compressor clutch fully engages or is soaked in oil because I haven't been able to locate it and am not sure how to verify if it engages.

So, I'm still in the place of improved, but inconsistent performance. Is there any risk in me monitoring this for a while, or do I need to be taking it in?

Thanks again for the help,
Brice
 
#9 ·
Catman -

Just let it run as-is; there's little "risk" aside from not having full AC cooling capacity.

The compressor is lubricated by oil that circulates with the Freon, but there's a low-pressure cutoff switch that prevents the compressor clutch from engaging if there's not enough Freon to properly circulate the oil.

The AC compressor is located on the driver's side of the engine, under the alternator. With the engine warmed up and idling, crouch down by the LH front wheel and have someone turn the AC on and off; you should hear a distinct click as the compressor clutch engages.

Find a reputable AC service shop, and ask how much it would cost just to have the system pressures checked. It will literally take less than 15 minutes. If it's more than $35-40, consider buying an inexpensive gage set. Harbor Freight offers a R134A gage set for $60. (It's the typical Harbor Freight low quality, cheaply-made Chinese import tool, but it will give you an indication of system pressure/Freon level.)
 
#11 ·
Catman if you hear a click when you turn it on then the a-c compressor is functioning.Now let the system run and listen for the click while running.If you dont hear any clicking or its clicking occasionally(long spaces between clicks) your system may be ok.If the clicking is rapid or happening alot the the system may be/is low on refrigerant.
To protect the compressor they put switches in the line to shut the compressor off when the pressure drops below a certain psi Hence the cycling on/off of compressor clutch.
 
#12 ·
gearwrench,
Thanks for the response. I measured about 15 to 30 seconds between clicks. Interestingly, the air conditioning functioning was very good during the time that I tested it and since I have cleared a significant amount of mud off of my radiator and compressor coils.
Brice
 
#14 ·
See step from 4 FJtests post. You're wasting your time. Find a set of gauges and verifying your operating pressures is the first and most important step. It provides you with your troubleshooting base information and from there you can proceed with looking at other issues , electrical, dirty condenser ect.
 
#17 ·
I'm not getting into a back and forth on this with you.I've been doing it for years and R12 was pretty stable as far as psi to temp is concerned,R134 is less so.I'll keep doing it the proper way and let it up to you to watch psi.Also to call me dishonest is far from true and to have you insinuate that is just plain wrong.
 
#18 ·
GW -
No one called you (or insinuated that YOU were) dishonest. You made no mention that you are associated with an AC shop ("most shops") that dumps & refills refrigerant without checking pressures.

I fully agree that dumping & refilling is the correct response IF you have clear evidence that the system has been contaminated with moisture or the wrong refrigerant by some amateur mechanic.

(If you check the temperature/pressure data for R12 and R134A, you'll see that they are very similar, around 10% difference between 40 and 110 F.)
 
#19 ·
watching and taking notes :lol:
 
#20 ·
Thanks for the advice everyone. I even appreciate different perspectives and think it's important to get different viewpoints. I am still deciding what I am going to do; either monitor it or take it in. I simply don't have the tools or knowledge to do the pressure check. On one hand, the functioning seems to be improving; either over time or with my additional cleanings. On the other hand, the compressor clutch does seem to be engaging a bit too frequently and there are times when functionality still doesn't seem 100%. I will let everyone know how things work out, for others with similar circumstance.
Thanks,
Brice
 
#21 ·
I decided to take my truck into a shop that does A/C and has a good reputation (not Toyota). They measured the pressures and said that "they were all over the place". They also said that the area between the radiator and condenser was still really dirty, despite me having cleaned it about five times the best that I could. They ended up cleaning the condenser and evacuating and refilling the refrigerant and said that they got the pressures stabilized. The A/C is now working well, but the compressor clutch is still cycling at the same 15-30 seconds. Any thoughts on this?

Thanks,
Brice
 
#24 · (Edited)
I decided to take my truck into a shop that does A/C and has a good reputation (not Toyota). They measured the pressures and said that "they were all over the place". They also said that the area between the radiator and condenser was still really dirty, despite me having cleaned it about five times the best that I could. They ended up cleaning the condenser and evacuating and refilling the refrigerant and said that they got the pressures stabilized.
As I was reading this. and while everyone was giving really good advice and directions, I was thinking that this action you took was the appropriate thing to do in your situation

The A/C is now working well, but the compressor clutch is still cycling at the same 15-30 seconds. Any thoughts on this?

Thanks,
Brice
I believe that my A/C is working correctly,as designed, and I hear my compressor cycle on and off occasionally. Don't worry about it and enjoy... you probably won't even need the A/C for much longer this year!
Don't worry about being so binary... on-off-on-off-on-off
 
#22 ·
It may be how the sysytem operates.I never had problems with mine so i never payed attention.If i get time tomorrow I'll look at mine and see.If its cooler up north it will cause the pressure to be lower in the system which could cause the cycling.If it's working and they're a reputable shop I wouldn't worry about it.
 
#23 ·
"Your condenser is frozen up. This is probably due to the system being low on freon."

"Leave the Air Conditioning Unit[/URL] off for 24 hours before you bring out the service tech or they wont be able to do anything."

How can a condenser "freeze up"? The condenser is where the hot Freon gas first goes after being compressed and heated by the compressor. The compressor and condenser are always the hottest parts of the AC system.

How would being low on Freon cause any part of the system to "freeze up"?

What would leaving the AC unit "off" for 24 hours accomplish?
 
#26 ·
I haven't read all the replys yet, but if it's been wheeled...
the cheapest thing to try first is wash down the radiator. If it's got mud and dirt in it, that will inhibit how well the AC works.
I was having the same problem, and although I hosed down the engine compartment, I didn't spray out the radiator.
Someone in the Texas threads recommended it to another member and I tried it. Not only did I wash out what looked like 5 lbs of East Texas red dirt, my AC worked WAY better.
 
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