Technical aircon us

[jim pratt]

Hi there all,i am anewby to the forum but i have an old problem.Its my climate control, i know theres a lot on here about it but i cannot find an answer to my particular problem.The system is gassed up ok, the compressor spins when you activate it but there is never a whiff of cold air.Surely someone else has had the same problem?Help! jp

 

[T14086]

is the airflow strong? or do you mean its hot all the time?

 

[jim pratt]

Its hot all the time,flow is ok ,i have changed the pollem filter

 

[keviwal]

Hi,
Have you triede a reset on the climate comntrol?
Start the engine then push and hold both buttons ( auto and mono) for more than 5 seconds, it should go through an auto calibration sequence.
I,m sure this is correct as i did on mine . I,m sure someone will be along very soon if i,m wrong !!

Cheers,

Kev walker

 

[jim pratt]

Thanks for posting mate ,but tried it and still no joy
jp

 

[sixpotman]

Do any of the aircon pipes get cold to touch?

John

 

[cris1117]

Hi
Had exactly the same problem on my 206 the compressor was spinning up but no cold air. Had it re gassed at Halfords, waste of time a spotty kid with a can of gas obviously didn’t know what he was doing tried for about 10 minutes then gave up.
Took it to kwik Fit they connected it to a machine which emptied the complete system checked for leaks then re gassed both the high and low pressure sides of the system, works great now.
It cost £49 but if it doesn’t work they don’t charge you, so nothing to lose.
It takes best part of an hour to complete, so I guess anything quicker is just the low pressure side being topped up.

 

[keviwal]

Hi Jim,

Ah well just a thought, nothing ventured and all that.
I had mine regassed as it was cold but not very cold . When they connected it up to the regasser it only had 400g of gas , it should have 550g (MW).It was the best 50 quid i have ever spent. As cris said whizz it down to kwik fit and even if it doesnt work the you have lost nothing only an hour of your life !
Good luck and i would like to hear if you do get it sorted

Cheers

Kev W

 

[jim pratt]

Hi all,
gas pressure is fine,no cold pipes but the high side pipe into compressor is very hot. Has anyone heard of an issue with a flap that diverts the cold air from the matrix into the car?
jp

 

[Deckchair5]

If your expansion valve (where the charge point is) isn't extrememly cold to the touch with visible condensation on it then there won't be any cold effect in the cabin

What's the history with this? Is this a system that has never worked in your possession? Been out of action for a while? Was the system checked and refilled professionally?

 

[jim pratt]

the system worked last year.i topped it up with a can myself,i know its not perfect but it should work to some degree. its as if the gas is being compressed,hench the hot high pressure pipe but its not being allowed to circulate. this would explain why the low pressure pipe is not cold, wouldnt it?

 

[Deckchair5]

this would explain why the low pressure pipe is not cold, wouldnt it?
Yes as the compressor is obviously pumping for it to be so hot then either the mix is wrong or there is a blockage.

Getting the low side and high side pressures with system running gives the full story. A good air con engineer would be able to connect up gauges in minutes to give a fuller picture and most will do a free diagnosis

 

[jim pratt]

I have just partially destroyed my stilo trying to get to the bottom of this.First i found a wet patch oin the passengers footwell but luckily it wasnt a blocked drain just rain getting in somewhere!Next broken (cheap) plastic trim to access the heater box etc,all flaps working ok so it must be a blockage in the system,i dont buy the wrong mix /pressure imbalance because if the high pressure pipe is too hot to touch there must be some sort of pressure in there.I feel so foolish buying a Fiat, and i would sell it tomorrow but we all know they become virtually worthless overnight ,even when bought second hand.I wish i had never seen the pile of s&#!e.

 

[Deckchair5]

Well look, if there was no refridgerant in the system ie a totally wrong mix then the system would get hotter and hotter with the work done by the compressor until it self destructed.

If an aircon engineer connected up low side and high side gauges then a blockage at the evaporator valve ( very common as it's a very small nozzle) or the filter/dryer would show up straight away

Take it to an aircon engineer, their advice is often free and it's up to you whether you take it

 

[cris1117]

Hi
When I had mine topped up at Halfords with a can it made no difference at all, the pressure was fine on the low side of the system the compressor was working but no cold air.
I don’t think air con is really a diy job unless you have the right gauges and the experience to determine what the readings are telling you.

 

[Deckchair5]

I agree, when it comes to problems then there are weird things that can fox even the most experienced air con engineer. But there are some very simple and safe tests you can do.

Not many people have the low and high side aircon pressure gauges and it's pretty dangerous if you get it wrong but air con is all about temperature and most people have a thermometer of some sorts. Manuals seem to go on about testing the temperature at the face vents but you could sit there for ages waiting for things to happen and a blocked cabin filter or poor air flow will still leave you scratching your head wondering where the problem is. It will depend on the ambient temperature and temperature in the car cabin too. In the meantime you're sweltering wondering when things are going to happen

Go for the more raw stuff of "is the aircon cooling properly?" because if that's not then you're wasting your time sitting in the cabin with that puzzled look on your face

At the aircon refill point there should be a huge difference in temperature within minutes of starting the air con at the two pipes there.


That's your low pressure/low temp and high pressure/high temp pipes right there. Outside temp is 18C today


Here's low side temp after 2min from start up, thermocouple directly on the low pressure/cold pipe

and high side temp after 2min, thermocouple directly on the high pressure/hot pipe
so it's already showing a difference of 34C

4 minutes after start up

low side temp


High side temp

So now there is a difference of 45C and we can't go much lower than 4 degrees without safety devices stopping the aircon compressor

So you have already worked out in minutes that your air con is cooling well. If you're not getting the cold air into the cabin then you know you have an air distribution fault like blocked cabin filter or blower or distribution flaps because you can see that 4C is available, you just have to get it circulating in the cabin

To find faults then you need to have a clear grasp of how the A/C works without getting into mind blowing detail and this explains it pretty well and, for once, the system diagram is very similar to the Stilo

http://www.mistermatic.co.uk/aircon/theory.htm

 

[jim pratt]

Thanks for that Deckchair,i would give you an official thank you if i knew how.I can see you have put a lot of thought and effort into solving my problem.
To recap, everything that is visually checkable is fine,such as,hot side gas prssure,pump clutch,heater/aircon box flap operation,matrix drain clear.
As far as temperatures go, after say 5 mins of engine starting high pressure pipe is almost too hot to touch,low pressure pipe is at ambient temp,from which i assume coolant is not circulating

By the way i am liking the m&s advert on the front page!

 

[sixpotman]

Thanks for that Deckchair,i would give you an official thank you if i knew how.

Bottom right hand corner of Deckchairs post

Thumbs up button = Thanks

John