# air condition high heat?



## carpdad (Oct 11, 2010)

It's 1998 toyota camry. I have no cold air but only when it's turned on when engine is hot, like when driving for while, park and come back. Cool engine after some time or driving for 10 minutes or so makes the AC function again.
I may have over filled the freon. Belt feels tight enough. Belt is fairly new, changed and checked with belt tightness tool when the timimg belt was done.
Any guess why AC doesn't work only when engine is hot? I agree that it is a temperature problem but I don't know anything about auto AC system.
Thank you in advance.


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## huesmann (Aug 18, 2011)

Some cars have a thermal switch that opens when the compressor gets too hot (on some cars, the switch even fails in the open position, permanently). I'm not familiar with Camrys, so can't confirm if that's a problem with them.


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## Fix'n it (Mar 12, 2012)

make sure the fan/s are working.


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## quatsch (Feb 4, 2021)

Hayne's Chilton manuals may give you a schematic. Find the thermal overload switch.


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## carpdad (Oct 11, 2010)

Thank you all. Will check on them.


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## ukrkoz (Dec 31, 2010)

THere is NO WAY of telling, if all mechanics work properly, without having gauges on the system and pressure diagnostic. NO WAY.


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## Brainbucket (Mar 30, 2015)

Got to have pressure readings, High and low at 1500 rpm, before any diagnosis can be made.


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## quatsch (Feb 4, 2021)

One strategy among several: 
Do the easy stuff first. 
You could get lucky. If not, at least you know what component is not the problem.


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## argile_tile (Aug 1, 2020)

DO NOT forget to check your mixing door. (this door controls the flow of air through your HOT AIR RADIOATOR UNDER YOUR DASH and your COLD AIR). if that door is stuck, and often it is, it will appear like you have no cooling after the car warms up.

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Get your car to 190 deg, go home. "hotwire" your compressor to come on at your command but do NOT leave it on for more than the normal run-cycle time either. You MUST have the fan on speed 2 or 3. If it cools and is not noisy running - then you may guess it's not your AC system but some a "indoor temperature controls" or sensor issue.

agreeing with people above you have to use guages MINIMALLY: but you have to WEIGH IN refrigerant you can't just pop freon in it by guages unless you know what your doing (unless a youtube video trying to sell you freon tells you to?) your all screwed up. you can't weigh in unless you first weighed out in your case. you need to post in the HVAC channel for someone to tell you how to find out whether your overcharged or not or have the dealer insure your not overcharged. OR learn to use guages and diagnose the meanings and have charts and your model data. (it depends on mfg design, ambient temperature, operating condition (if running or not running), and their $6,500 Robinair unit has car models built-in to it). it's not something where you just stuff in freon. And you should know you can't just "let it out" that it's bad for the environment.


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## carpdad (Oct 11, 2010)

Another thanks for all replies. 
For now, I have cold air (as much as I want) as long as engine can cool. By that I mean that I don't know what/which AC part is hot or getting heated (by engine). Although my own newby logic is saying why would freon pressure matter, since it does work as long as I start the AC when the car (including the engine and AC parts) had time to cool or cooled while driving. Another word I remember now is "heat soaking". It is as if some part of the AC system is heat soaked and gives me those blinking AC light and no cold air.
I started doing some reading on auto AC. It looks like there are at least 2 parts that stops the compressor from working. Thermistor and expansion valve, both of which can be affected by car's heat. 
Also watching some videos and it may be possible to learn this from the videos. Pressure gauge looks cheap enough. Vacuum pump may be rented. Not sure about anything for now but I'm seeing some potential for diy. Thank you all for the help.


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## Fix'n it (Mar 12, 2012)

did you check that the condenser and radiator are not dirty ? i have seen them where between the 2 was so bad idk how the engine didn't overheat.


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## HamiltonJoanne (Jul 5, 2021)

Yes, cleaning it might work. When my car aircon wasn’t giving me cold air, that’s what I did, and I am glad that it worked out. Unfortunately, I had the same issue with my regular air conditioner at my house. I tried to clean it, but still, the aircon not cold at all. I decided to look for a solution online to fix the issue because where I’m from, it’s impossible to survive without an air conditioner. I was lucky enough to find a really good website, and I was able to see all the information needed. There was a guide on fixing an air conditioner, and thanks to them, I was able to fix my issue. That’s why I’d love to recommend them to everyone who is facing the same issue.


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## Brainbucket (Mar 30, 2015)

It sounds like you have too much freon in the system. When it's cold, high side is not as high as it is when vehicle is up to operating tempature making the high side over pressure switch to cut power off from the compressor. Or your fan isn't working properly.


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## Gottawireitup (Dec 15, 2018)

Brainbucket said:


> It sounds like you have too much freon in the system. When it's cold, high side is not as high as it is when vehicle is up to operating tempature making the high side over pressure switch to cut power off from the compressor. Or your fan isn't working properly.


Yes. Also you said you may have over filled it. Check again with a gauge. More is not good. Will not work if overfilled properly. 


Sent from my iPhone using Tapatalk


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## poulsenar (Sep 6, 2021)

I had the same issue a few months ago with my honda civic, and it turned out that my AC wasn't working because of electrical problems. This could be your situation as well, since a few broken wires can also damage the engine as well as the air conditioner, making your car very hot. A visual inspection of all the wiring can help you see if any wires are broken or frayed. It will help if you read this https://www.socool.sg/why-is-your-aircon-not-cold/ article. They explain the reasons why your AC might not be working very nicely. It also helped me when mine wasn't working.


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## HotRodx10 (Aug 24, 2017)

Brainbucket said:


> It sounds like you have too much freon in the system. When it's cold, high side is not as high as it is when vehicle is up to operating tempature making the high side over pressure switch to cut power off from the compressor.


This would be my best guess as to the source of the problem. You want a manifold gauge set to check it.


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