Need a Quick Consult on A/C

[Killer Instinct]

Hello everyone,

Long time occasional lurker here, I've enjoyed reading the helpful tips and posts and I think this is a great community.

I drive a 2002 Gen 4.5 I4 Camry (Australian built). I've been having some trouble with the A/C, basically its not as cold as it used to be. Now I know that this is subjective but the A/C used to be freezing cold during the humid desert nights of Qatar (in the Gulf near Saudi if your geography is rusty), now its just acceptably cold. I've had the refrigerant pressure checked and its fine. Both cooling fans are running fine as well. I had the car jack washed a couple of days ago so everything underneath is nice and clean and its not likely a dirty evaporator or something like that. I've also noticed that while the cooling does improve at speed, its still not as good as it should be.

After lots of browsing these forums I started to suspect that the heater control valve might be the problem since everything else seems fine. So I popped the hood and took a look, this is what i see in the right side of the engine bay near the firewall:



The valve with the bicycle brake wire goes through the wall into the cabin, I double checked that this is what I'm looking for by going into the car and turning the temp knob and the valve does in fact turn. I felt the two pipes behind the valve and both of them are quite noticeably warm to the touch. Does this signify a faulty valve? If so can it be DIY or should I take it to a shop?

Thanks in advance!

[skuttduck]

Originally Posted by Killer Instinct

Hello everyone,

Long time occasional lurker here, I've enjoyed reading the helpful tips and posts and I think this is a great community.

I drive a 2002 Gen 4.5 I4 Camry (Australian built). I've been having some trouble with the A/C, basically its not as cold as it used to be. Now I know that this is subjective but the A/C used to be freezing cold during the humid desert nights of Qatar (in the Gulf near Saudi if your geography is rusty), now its just acceptably cold. I've had the refrigerant pressure checked and its fine. Both cooling fans are running fine as well. I had the car jack washed a couple of days ago so everything underneath is nice and clean and its not likely a dirty evaporator or something like that. I've also noticed that while the cooling does improve at speed, its still not as good as it should be.

After lots of browsing these forums I started to suspect that the heater control valve might be the problem since everything else seems fine. So I popped the hood and took a look, this is what i see in the right side of the engine bay near the firewall:



The valve with the bicycle brake wire goes through the wall into the cabin, I double checked that this is what I'm looking for by going into the car and turning the temp knob and the valve does in fact turn. I felt the two pipes behind the valve and both of them are quite noticeably warm to the touch. Does this signify a faulty valve? If so can it be DIY or should I take it to a shop?

Thanks in advance!

Are you sure about the Refrigerant level though? My 2000 started out that way, and last year I finally had to put some more R134a in the system. My uncle noticed something that my car had, that yours might have.

In front of the radiator is a filter dryer for the AC system. It has a view hole on it similar to ones you see on the battery. It is on the passenger side of my car. Not sure if it is on the Australian built car. If you turn on the AC in your car, and you see air bubbles in there, your system is low on coolant. There should only be a few bubbles when the system is shut off. This information is also in the manual at the camrystuff website.

I put one jar of R134a refrigerant in the car and thought I had enough as the AC was really cold. Then he showed me this, and it needed two.

[1996camry]

did you remove old refrigerator before you put new 134a in your system? you have to remove old refrigerator out then put 134a in your car in order your car gets cool.

[skuttduck]

Originally Posted by 1996camry

did you remove old refrigerator before you put new 134a in your system? you have to remove old refrigerator out then put 134a in your car in order your car gets cool.

No I didn't vacuum the system, and remove the existing refrigerant. The way car systems are designed, they leak after several years. I merely topped off my system using a recharge kit.

[Stillrunning]

Unless the system has been exposed to air no need to evacuate first. The heater valve or blend door may be your problem. I would get one of those hose clamp tools and squeeze the hose from the engine to cut off any water and see if the cool improves. Does the car cool ok at speed and not too well at idle in traffic?

[davemac2]

Lackluster cooling can be different things.

If you suspect the heater valve or bypass door, then running the A/C in the morning just after a cold start should give you much colder vent temps since the engine temp will not be high enough to contribute heat to the heater core. Use a thermometer stuck into the middle vents to give you some actual measurements to compare.

If there is some partial blockage of your A/C condenser out front, or your rad fan(s) is in the process of dying and not operating at full speed, that can also diminsh cooling capacity. One thing you can try is to run the A/C and hose down the rad and condenser from the front and see if cabin vent temps are affected much.

The other possibilities are either refrigerant level, air or moisture contamination in the system, a weak compressor, blockages, or a misbehaving expansion valve. Any of these causes should show up in pressure readings and compressor cycling behavior. A decent A/C tech should be able to diagnose it. You may want to get a second opinion on your pressure readings.

If your A/C system temp control is electronic and includes cabin temp sensors, that's another possibility.

The 'bubbles in the site glass' thing is supposedly more applicable to R12 rather than R134-A, but if you are out of options and you will likely need to have the system opened up and recharged, I would try adding half a can of R134-A anyways just to see what happens. (should be your last option though).

dave mc

[Killer Instinct]

Thanks for the replies everyone and I'm sorry I'm so late to respond - time zone difference I think.

Originally Posted by skuttduck

Are you sure about the Refrigerant level though? My 2000 started out that way, and last year I finally had to put some more R134a in the system. My uncle noticed something that my car had, that yours might have.

In front of the radiator is a filter dryer for the AC system. It has a view hole on it similar to ones you see on the battery. It is on the passenger side of my car. Not sure if it is on the Australian built car. If you turn on the AC in your car, and you see air bubbles in there, your system is low on coolant. There should only be a few bubbles when the system is shut off. This information is also in the manual at the camrystuff website.

I put one jar of R134a refrigerant in the car and thought I had enough as the AC was really cold. Then he showed me this, and it needed two.

Yes the dryer is there in front of the radiator, I turned on the A/C and the view hole was perfectly clear, no bubbles. I took the car to a shop, the guy connected it to a pressure gauge which apparently showed that the refrigerant level is fine. Some of the lines in the engine bay are freezing cold to the touch which is another reason why I don't think that's the problem.

Originally Posted by Stillrunning

Unless the system has been exposed to air no need to evacuate first. The heater valve or blend door may be your problem. I would get one of those hose clamp tools and squeeze the hose from the engine to cut off any water and see if the cool improves. Does the car cool ok at speed and not too well at idle in traffic?

Hmm I should try that, would I notice any improvement right away or do I have to keep it clamped until the water trapped in the heater core cools down? About the cooling, it improves at speed but the overall cooling level is still way less than it used to be.

Originally Posted by davemac2

If you suspect the heater valve or bypass door, then running the A/C in the morning just after a cold start should give you much colder vent temps since the engine temp will not be high enough to contribute heat to the heater core. Use a thermometer stuck into the middle vents to give you some actual measurements to compare.

I was in a hurry this morning so I didn't have a thermometer handy, but the temperature of the air was better immediately after a cold start - temperatures here in the summer are never lower than 40C so I wouldn't exactly call it cold but still -.

Originally Posted by davemac2

The other possibilities are either refrigerant level, air or moisture contamination in the system, a weak compressor, blockages, or a misbehaving expansion valve. Any of these causes should show up in pressure readings and compressor cycling behavior. A decent A/C tech should be able to diagnose it. You may want to get a second opinion on your pressure readings.

I will do that today.

Originally Posted by davemac2

If your A/C system temp control is electronic and includes cabin temp sensors, that's another possibility.

Nope, manual control here, no fancy sensors in my car.

I will post back with new info as soon as I have it, thanks again everyone!