Air Con Help Required

[alan333]

Hi,

My air con doesn't seem to blow cold any more. When momentarily pressing the tyre style valve on the pipe at the bulkhead there is air/gas under considerable pressure escaping. When switching on the A/C button the light comes on and with the engine idling the revs increase a bit then settle after a few seconds. The same happens when it is switched off again. Therefore I'm suggesting that the electrical side is ok, that there's gas in the system, and that the compressor is working. The day after I bought the car (2 years ago) Toyota "regassed the system" under warranty as the system wasn't blowing cold. This cured the problem but it never was the most effective air con I've ever had.

Any ideas?

Avensis 1.8vvti, 05 plate, 75k miles, manual heater, pollen filter replaced 2 years ago.

Regards

Alan

[igormus]

Hi,

My air con doesn't seem to blow cold any more. When momentarily pressing the tyre style valve on the pipe at the bulkhead there is air/gas under considerable pressure escaping. When switching on the A/C button the light comes on and with the engine idling the revs increase a bit then settle after a few seconds. The same happens when it is switched off again. Therefore I'm suggesting that the electrical side is ok, that there's gas in the system, and that the compressor is working. The day after I bought the car (2 years ago) Toyota "regassed the system" under warranty as the system wasn't blowing cold. This cured the problem but it never was the most effective air con I've ever had.

Any ideas?

Avensis 1.8vvti, 05 plate, 75k miles, manual heater, pollen filter replaced 2 years ago.

Regards

Alan

hello

have the system vacuumed first and change pollen filter -- after that revert with outcome.

The most probably you have a leak thru those wheel type valve.

Cheers/Igor

[alan333]

hello

have the system vacuumed first and change pollen filter -- after that revert with outcome.

The most probably you have a leak thru those wheel type valve.

Cheers/Igor

Cheers for the reply but there is lots of pressure in the system - surely there wouldn't be any pressure if there was a severe leak?

Regards

Alan

[igormus]

hello

have the system vacuumed first and change pollen filter -- after that revert with outcome.

The most probably you have a leak thru those wheel type valve.

Cheers/Igor

Cheers for the reply but there is lots of pressure in the system - surely there wouldn't be any pressure if there was a severe leak?

Regards

Alan

OK -- you have sufficient pressure, as you suggest -- but you have no cold air?????

if you have no cold air -- this means the throttle valve or compressor are out of order. You must also be sure the heat exchanger converts gas into liquid -- otherwise the refrigeration cycle is violated.

Cheers

[alan333]

if you have no cold air -- this means the throttle valve or compressor are out of order. You must also be sure the heat exchanger converts gas into liquid -- otherwise the refrigeration cycle is violated.

Cheers

Thanks for getting back again. I reckon the compressor is working too as the engine revs change for a few seconds when I switch the A/C button on or off. How do I check the throttle valve?

Regards

Alan

[igormus]

if you have no cold air -- this means the throttle valve or compressor are out of order. You must also be sure the heat exchanger converts gas into liquid -- otherwise the refrigeration cycle is violated.

Cheers

Thanks for getting back again. I reckon the compressor is working too as the engine revs change for a few seconds when I switch the A/C button on or off. How do I check the throttle valve?

Regards

Alan

Hi Alan

The compressor is only rotated !!! If you observe rpm insreasing then both el clutch and engine rpm sensor are in order. But if the system is short of 134a or it has a leak or a minor air is present there -- this might be the main reason. Firstly you have to visit an A/C repair workshop that regulary does this job --- they will have full system vacuumed to be sure the system has no vacuum dropping (leak)-- only afterwards they will recharge system with 134a again in quantity specified under the bonet as sticked name plate (in common cases). You should not strictly state that your compressor is in order unless it was tested in the private work shop. Check and revert. Besides -- have an A/C left running and touch both tubes joined the compressor -- the one of them (normally has smaller dia) must be hot -- this means the 134a vapours are compressed and pushed to condenser (those small radidator in front of your cooler radiator)for being converted into liquid before throttle valve for expanding/boiling. The other tube (normally is bigger dia)is suction (from evaporator behind your glove box)must beb cool with character condensation on it's surface especically when atmospheric air is warm. Chceck and revert/Cheers/Igor

[alan333]

Cheers I'll do a test on the pipes and then it's probably a visit to my A/C shop. Thanks for the input it's much apreciated.

Regards

Alan

[The Cav]

I am lead to believe that if there is no gas present in the system then the compressor on the A/C will not work

how true that is i dont know

[alan333]

I am lead to believe that if there is no gas present in the system then the compressor on the A/C will not work

how true that is i dont know

I'm under the same impression myself. There's definately some sort of gas or air under a lot of pressure in the system, and the revs change when switching the A/C on or off. I'll need to investigate further.

Cheers

Alan

[igormus]

I am lead to believe that if there is no gas present in the system then the compressor on the A/C will not work

how true that is i dont know

I'm under the same impression myself. There's definately some sort of gas or air under a lot of pressure in the system, and the revs change when switching the A/C on or off. I'll need to investigate further.

Cheers

Alan

Alan

hi

I wonna draw your attention to the fact that if the system has not been de-aired before re-gasing -- this air with moisture do the job to block the throttle orifice by an ice -- why an ice??? -- the explanation is very simple --- the main task of the throttle valve is to reduce pressure of R134a until it boils -- the boiling point of R134a is less then freezing point of water(moisture)--> as the result this moisture is cooled down untill freezing point and finally got frozen keeping throttle orifice blocked -- > and finally compressor's clutch is OFF by a signal from ppressure sensor on the tube. You can find this one having investigated system. DO not lose the time but visit work shop and leave this job to them. Good luck/Igor

[alan333]

Problem fixed. The system was low on gas right enough. Apparently it had 10 grams of gas when it should have 450 grams. No leaks.

Thanks for the input guys :)