Technical Air Con

[Deckchair5]

"Something i have noticed when i press the air con button inside car (snowflake) it lights up as it should but i dont hear the engine increase or rev counter dont change, is this because the pressure in a/c system is below a certain point"
Yes, provided you have the max cool set then the compressor clutch should engage which it isn't on yours by the sound of it. Have a look at the end pulley of the compressor-the centre part- the electric clutch - should be whizzing around too with the pulley when you select air con- if it's just sat still then the most likely cause is the linear pressure sensor isn't happy with the pressure in the system so is not allowing it to start. All points to low pressure in the system

 

[kevhky]

Hi

Deckchair5

Ive bought diy refrigerant and topped system up today using a guage (pretty straight forward),

Now when i press the a/c button the engine picks up and rev counter moves, so obviously enough pressure in system now for a/c to start,

I never had to put much refrigerant in the system to meet the correct pressure.

Ive only tried it for around 10mins, it didnt seem to get really cold,

Do you think air may be present in the system not leaving much room for the refrigerant before system is showing full,

Is this what generally happens or am im being impatient and more time needed for air temp to really drop (I thought air would be icy cold)

Kev

 

[Deckchair5]

When it's working properly it will be ice cold out of the vents. Only takes 5 minutes to notice

Is the compressor clutch engaging? Look at the compressor pulley with the engine running, the outside pulley will be rotating all the time but the clutch will only engage and the inner part start rotating when told to do so by the A/C switch, set to cold and enough pressure in the system. Once it's working then you'll know by the sound when you select the A/C, if it's never been working then you can sit there wondering if it's actually going or not

Air con engineers will pull all the air/gas out of the system, vaccuum test it then refill so you get a full charge. If you've lost the lot so it's now full of air then it's probably your only option to have it professionally checked and refilled

 

[kevhky]

Cheers

I may sound dumb here but where are you talking about to check for compressor/pulleys

Is it on the drivers side of engine which im assuming

Also if i were to release all air/refridgerant through valve until it stopped releasing, then done a refill would this work or not

Kev

 

[Deckchair5]

Yes driver's side, look for the most forward pulley of the bunch and that's your compressor drive pulley. With the engine going the pulley rotates but doesn't drive the compressor until the electro clutch is engaged, that's the centre portion of the pulley. If the compressor isn't being driven then no air con.
The electro clutch only operates when A/C is selected, temp control is low enough, gas pressure in system is within limits and a few other switches tell it that's it's ok to run. So start engine, turn on A/C, select max cold and see if the compressor is being driven by checking the centre of the compressor drive pulley

As regards gas, just pumping in gas on top of a system full of air isn't so good. It might work but inefficiently. Better to vacuum down the system and refill

 

[kevhky]

Hi

Yes compressor is working ok, checked everything youve mentioned and it is working fine,

I done what i mentioned let all air/gas out of system and refilled, now you can feel the difference when the a/c button is pressed, the air blowing through does get a lot colder.

Ill wait for a nice warm day to test it fully

I must thank everyone who has helped on this thread/forum as i could never have done this on my own.

Im sure this thread will be helpfull to others who need advice on the air con

Thanks

Kev
(im now gonna attempt the cruise control stalk)

 

[Squadrone Rosso]

Aircon - a total 8 months @ 700 miles a week without it. The main reason for geting shot of my Stilo. The dual zone climate on my 156 isn't the coldest mind you......

 

[kevhky]

sbaddison

So you are saying the air con on your car when switched on max cold is not icy cold.

Like i said need a hot day to give a proper verdict but it is now working

Kev

 

[Squadrone Rosso]

Yes. On the LO setting on the 156 it's cold but not icy. When the aircon on the Stilo was working, it did seem colder but somethings better than nothing IMO. Would have kept the Stilo if not for that. Nice car but the 156 is better in every aspect except practicality and was good value. 1 yr old direct fro Fiat UK with 8 k on it for £10490!! Paid more for my 8 month old Stilo :-o

 

[wotnowarninglight]

When its working properly on my Stilo it is Ice cold... if you hold your hands over an open dashboard for a minute or so the joints in your fingures should start to hurt (that cold!) Its just that the 4th time the Aircon will need attention in 10 n a half months of ownership BUT this summer predicted to be a '76 style scorcher

 

[kevhky]

(if you hold your hands over an open dashboard for a minute or so the joints in your fingures should start to hurt (that cold!))

Ive held my hand 3/4 inches from a vent while a/c is not on for a few mins and yes its cold but dont hurt, so i kept my hand in same place and hit the a/c button and you certainly can feel the difference straight away after a min or two hand starts to hurt

Its just that the 4th time the Aircon will need attention in 10 n a half months of ownership

Are you saying your aircon has had attention in the last 10 1/2 months - Blimey thats alot, what keeps going wrong

Kev

 

[Deckchair5]

They just leak- all car's air cons do and some leak more than others. Finding a small leak is much worse than a big one. It's 25psi being held in by o rings of rapidly temperature changing, flexing joints. If you're lucky to get a perfectly sealed system it still bleeds out around 15% each year which is why they need topping up every 2 years or so

The air con is great though , not just for the cooling - it makes the moisture bump off the screens and makes it much more pleasant in the car on a fuggy day. I use mine a lot through the winter too. Best to put it on every week no matter what the weather.

 

[PNL]

Good mornig deckchair5 can you tell me what a fuggy day is as we dont get fug down here in Wales

 

[Deckchair5]

It's what's left in the air after the moisture from the Atlantic has dumped its storm clouds over South Wales and Birmingham

 

[kevhky]

Hi all

Okay borrowed a sensitve air temp thermometer from work and thought id test temp of air con,

These were the results

travelling at around 60mph max cool and blower on full (not aircon) with probe stuck in vent temp dropped down to 12.8 deg C

Then flicked the aircon switch it dropped to 4.9 deg C and was still very slowly dropping but i arrived home.

Well impressed with it. (1 week ago it wasn't working) all i done was topped up with refrigerant

Kev

 

[Deckchair5]

That's really good. Nice when it works isn't it

 

[wotnowarninglight]

(if you hold your hands over an open dashboard for a minute or so the joints in your fingures should start to hurt (that cold!))

Ive held my hand 3/4 inches from a vent while a/c is not on for a few mins and yes its cold but dont hurt, so i kept my hand in same place and hit the a/c button and you certainly can feel the difference straight away after a min or two hand starts to hurt

Its just that the 4th time the Aircon will need attention in 10 n a half months of ownership

Are you saying your aircon has had attention in the last 10 1/2 months - Blimey thats alot, what keeps going wrong

Kev

Full run down... Aircon seemed ok on road test when I was in the process of buying the car. Then couple of weeks down the line ceased to function properly. Took the car to FIAT and they checked it said, faulty valve but not covered by third year warranty - charged me £58 for finding the fault though! Took it back to suppyling dealer whom fixed the valve. Subsequently one of the pipes fractured too! (as did one on dads 03 plate 1.6 16v Stilo) Back to supplying dealer for repair, where whilst in their care rear quarter light got smashed... they replaced the quarter light badly, scratched the paintwork and left broken glass on the back seat - bought to my attention by my 8 year old daughter, she had been sitting in it and asked whats this daddy?