Corolla aircon

[AnthonyMarrian]

The A/C in my 2024 Corolla Excel is cool but definitely not cold, not as effective as my 2019 Prius Excel. Is it possible that a new car would be delivered with insufficient A/C fluid?

[fred88]

Been wondering this about my 71 plate TS too. Measured amateurishy at the vent it drops to 10 C. It does the job but like you I've been wondering if it's right.

[SDR]

I have a 2024 TS.   I don't think that my ac is especially cold but neither do I think that it is very different to other recent cars that I have owned.

On (so far rare) hot days, I use the air recirculation feature which helps a lot (and means that the system doesn't have to work so hard).

The refrigerant used in car ac systems changed around 2017.   The new stuff is apparently more environmentally friendly.   

I do, however, have a sneaking suspicion that it may not be as effective as the previous stuff.   I've no objective evidence for that, just a feeling that car ac systems with the new fluid are not as effective as they were previously.   Of course, there could be other factors at play, e.g. manufacturers deliberately reducing the effectiveness of ac systems in order to reduce their effect on fuel consumption and emissions. 

[taxidriver50005]

I wondered this myself... Plugged in obd reader and checked fin temperature against demanded temperature... Both read the same so that's working fine.... But as average temps are only about 20 degrees the demanded temp is about 10 degrees.. When we were a little warmer a few weeks ago demanded temp was 2 degrees and actual temp was 2 degrees also.

So the warmer it is the colder the system demands... Older systems just demand full cooling if you turn down temperature. 

[SDR]

5 minutes ago, taxidriver50005 said:

I wondered this myself... Plugged in obd reader and checked fin temperature against demanded temperature... Both read the same so that's working fine.... But as average temps are only about 20 degrees the demanded temp is about 10 degrees.. When we were a little warmer a few weeks ago demanded temp was 2 degrees and actual temp was 2 degrees also.

So the warmer it is the colder the system demands... Older systems just demand full cooling if you turn down temperature. 

Interesting.   So we have 'smart' ac to go with all the other smart systems. 

It seems that the days of freeze-your-face-off aircon are gone forever 😢 

[fred88]

Sorry if I'm being thick but what are fin temperature and demanded temperature in the context of your post.

[fred88]

1 minute ago, SDR said:

Interesting.   So we have 'smart' ac to go with all the other smart systems. 

It seems that the days of freeze-your-face-off aircon are gone forever 😢 

Agree, in fact it's one of the reasons cancelled a diagnostic and regas appointment recently. 

[taxidriver50005]

26 minutes ago, fred88 said:

Sorry if I'm being thick but what are fin temperature and demanded temperature in the context of your post.

I'm no expert but I was playing about with the torque app and found these relate to air con... I'm assuming the fin thing is similar to a heater matrix only instead of heat it's cold, so the fin is how cold output is of air con is.... The hotter it is outside the colder it needs to blow to cool car. 

Or I may be totally off base

.. Any experts out there

[TonyHSD]

Your cars has eco function built into the hvac software which will limit the ac output to preserve energy and been more efficient. Anything eco just brings negatives been on tyres, on hvac, on everything.
Just make sure this function it’s not activated, use hvac settings in normal mode, auto ON with AC ON and don’t click recirculating mode, these will be automatically controlled by the car, temperature set at 22C° or similar, car in normal drive mode too. These are the important things. The refrigerant gas inside the system it’s not a reason for lower output. Plus outside weather it’s not hot enough to make ac working hard enough to cool down the cabin . The sun or the lack of it makes AC work harder to blow cool air or works mediocre to cool down cabin slowly, sensors built in the top of dashboard control that. 

[Roker]

On 7/7/2024 at 9:30 AM, SDR said:

I have a 2024 TS.   I don't think that my ac is especially cold but neither do I think that it is very different to other recent cars that I have owned.

On (so far rare) hot days, I use the air recirculation feature which helps a lot (and means that the system doesn't have to work so hard).

The refrigerant used in car ac systems changed around 2017.   The new stuff is apparently more environmentally friendly.   

I do, however, have a sneaking suspicion that it may not be as effective as the previous stuff.   I've no objective evidence for that, just a feeling that car ac systems with the new fluid are not as effective as they were previously.   Of course, there could be other factors at play, e.g. manufacturers deliberately reducing the effectiveness of ac systems in order to reduce their effect on fuel consumption and emissions. 

Old AC systems used to take a lot of power from the engine, so much so you could feel the car speed up when you switch it off . I cannot imagine an electrical driven AC pump could be as powerful as the old  belt  driven pump other wise the hybrid Battery would run down fast

[Cyker]

It does run down fast!!  

When we had that super hot summer a few years ago, I was stuck in a load of traffic and the engine would cycle back on every couple of minutes to charge the Battery because it kept getting drained so fast from the AC running hard! Normally it takes maybe 10 minutes to drain it low enough the engine needs to run.

I think the main reason modern AC systems don't seem as cold is they don't run all the time - With normal HVAC systems, like the one on my Mk1 Yaris D4D, when you turn on the AC on, it's ON.

But with climate control systems, 'turning on' the AC just gives the climate computer the option to use the AC or not; Because modern cars are so focused on economy, they tend to run the AC compressor as little as they can get away with to minimize the power drawn while still delivering the target temp (And I suspect maintaining humidity levels).

If I set the temp to LO and set the Eco mode to Fast, mine gets cold pretty quick  

[TonyHSD]

Actually the hybrids ac do get very cold air if it’s hot and sunny ☀️. 
I believe all ac compressors keep on and off as necessary to maintain pre set temperature and they never work constantly. On those with belt driven compressor and smaller engine the switch is very noticeable. 

[Steven83]

The hvac has a eco setting too which can be turned off. I think this effects the aircon.

 

also doesn’t running the car in eco lower the aircon output? I’m sure I read that in the manual.

 

 

[AndrueC]

HVAC systems never run the compressor continuously unless they've been set to a special 'cold as you can' mode. The core of an HVAC system can only produce one temperature. As with fridges and freezers the compressor will switch on and off as required to maintain the required temperature.

Even when set to 'cold as you can' the compressor will likely have to shut off occasionally in order to prevent excessive icing of the cooling coils.

[APS]

On 7/9/2024 at 3:18 AM, TonyHSD said:

Actually the hybrids ac do get very cold air if it’s hot and sunny ☀️. 

Switch on the torch on your mobile phone and rest it on top of the light sensor on the dash! Brrr...

 

1 hour ago, AndrueC said:

Even when set to 'cold as you can' the compressor will likely have to shut off occasionally in order to prevent excessive icing of the cooling coils.

Exactly this ^^ The compressor must switch off to defrost. 

 

On 7/9/2024 at 1:48 PM, Steven83 said:

also doesn’t running the car in eco lower the aircon output? I’m sure I read that in the manual.

Yes. Run the car in normal or power mode for better climate control. You clearly notice this during winter. Switch between normal and eco mode and the fan speed will differ a few notches. 

[Cyker]

You can override that - Maybe not in all of the models, but my HVAC has a button marked Eco Fast, so even if I put the car in Power mode I can press it to put the HVAC into Eco mode, or more likely if the driving mode is set to Eco, I can set the HVAC to Fast and then the inside of the car becomes like the Crystal Maze end dome but without the gold and silver flappy things blowing everywhere.