Air conditioner in a toyota avalon

Joined
Mar 30, 2020
Messages
1
Location
North Carolina
I have a 2009 toyota avalon. The a/c system has stopped working. The fan usually doesnt run but sometimes it comes on. If I take it off of recirculate cold air comes out the vents when I'm at speed. Today the fan came on but blew hot air. I tried to charge the system today since the fan was running at full speed but the gauge on the refrigerant pegged in the red zone. I dont believe it is overcharged, it acted like the refrigerant couldnt get through the valve and backed up into the hose. the compressor was turning on for about a second and then turning back off repeatedly.

Any ideas what may be wrong?
 
If it turns out to not be something simple like a bad relay...

You will probably not get accurate results trying to charge a system with one of those r134a cans with the gauge on it, as that gauge only measures low side pressure. The high side pressure is critical in making sure that a system is not overcharged.

If you don't have access to an r134a manifold gauge set, you really should take it to a reputable shop who can check the low and high side pressures properly. It will save you a lot of headaches in the long run. Trying to run a system with pressures too high, too low, too much or too little refrigerant oil, moisture or contamination in the system, etc. can cause expensive damage.

I hope it turns out to be a simple, inexpensive problem. Stay safe as well - released refrigerant can freeze body parts.

Andrew S.
 
Originally Posted by ChrisSnowden
I tried to charge the system today since the fan was running at full speed but the gauge on the refrigerant pegged in the red zone. I dont believe it is overcharged,


Isn't the red zone indicative of overcharge? The gauge reads the pressure of the system not just the hose. Why do you think the hose is plugged?
 
I assume you have a can with a low side gauge. If so those pressures do not mean anything. You need both a high and low side gauge to diagnose it and even that can be spotty with R134a. It needs to be properly charged by weight before we can do any diagnosing.
 
Pressures especially don't mean anything when the compressor is not running. It sounds like there is an electrical problem. The inside fan should always run with the switch on, the air selector works and the temperature dial changes from heated to ambient. Once all that works then you can look at diagnosing the A/C.
 
Originally Posted by ChrisSnowden
I have a 2009 toyota avalon. The a/c system has stopped working. The fan usually doesnt run but sometimes it comes on. If I take it off of recirculate cold air comes out the vents when I'm at speed. Today the fan came on but blew hot air. I tried to charge the system today since the fan was running at full speed but the gauge on the refrigerant pegged in the red zone. I dont believe it is overcharged, it acted like the refrigerant couldnt get through the valve and backed up into the hose. the compressor was turning on for about a second and then turning back off repeatedly.

Any ideas what may be wrong?

You mentioned the "Fan" usually doesn't run but sometimes it com es on"

Do you mean the radiator fan or the inside HVAC fan?

When filling the AC unit, the "COMPRESSOR" itself needs to be running(AC clutch engaged) in order for the system to accept refrigerant. I sound like some refrigerant went into they system. But in order to get a more accurate reading on the gauge, the compressor itself need to be running.

The radiator fan will turn on too when the AC clutch is engaged but, don't mistake a running radiator fan as the AC compressor being ON(engaged).
 
I do have some advice based on my experience. Please ask around and find a trustworthy and competent AC shop. From my experience, I have never been successful trying to self diagnosis any of my AC problems.
I bought the gauges, refrigerant, scales, etc. Wasted days of my life after work.

On my my last fiasco, after I had gone to the wrong repair shop at the tune of $1100, I called my local Lexus "dealer". They told me where they go. I called their guy and he said he seldom replaces individual components.
In my situation he would flush and replace "everything" with OEM parts and that would cost me $1300. If I had only known...

Something about how the lines can be contaminated and the only way to be sure is to replace it all. I now agree with him.

Why is it we seem to distrust AC repair men more than general mechanics?
 
Originally Posted by Gebo
Why is it we seem to distrust AC repair men more than general mechanics?


Why does a home window a/c unit at Home Depot that cools an entire room cost $99 while just the compressor for a car can be 3 times as much, is what I want to know.
 
On my 04 Camry, the difference between too little and too much refrigerant is two ounces. You need to take your Avalon to a competent AC technician. Had my refrigerant checked by dealer several years ago and invoice was $53. After fourteen years of service, no refrigerant was required. I think that is exceptional.
 
Cost of a compressor
Window unit- Compressor runs at one speed, fan runs at two or three speeds and any part that can be made of plastic is. The temperature that unit runs in 65-110*. And doesn't get bounce around.
Auto- Compressor runs from 800 to 5500 rpm and temps from -10 to 150*. Belt drive having to have a shaft seal and bearings to hold up. Refrigeration circuit design to put up with all the temperature difference (defrost to underhood to interior) , oil return and variable rpm.
 
Cost of a compressor
Window unit- Compressor runs at one speed, fan runs at two or three speeds and any part that can be made of plastic is. The temperature that unit runs in 65-110*. And doesn't get bounce around.
Auto- Compressor runs from 800 to 5500 rpm and temps from -10 to 150*. Belt drive having to have a shaft seal and bearings to hold up. Refrigeration circuit design to put up with all the temperature difference (defrost to underhood to interior) , oil return and variable rpm.
-10? Doubt that. I think the low pressure switch would long be open at that temp.On my Camry, the high/low pressure switch opens at 28 psig and 455 psig.
 
Originally Posted by Gebo
Why is it we seem to distrust AC repair men more than general mechanics?


Why does a home window a/c unit at Home Depot that cools an entire room cost $99 while just the compressor for a car can be 3 times as much, is what I want to know.
Central AC cost 50 times that, I want to know why too.
 
Back
Top