STeve

iTrader: (11)

My little ZS has a issue with the A/C as soon as its turned on I hear a loud clicking sound which i'm told does happen, when I attach a gauge to the A/C to check levels of gas the gauge rises into the green area then drops off to zero then raises again to green and does this every 7 seconds and is not cooling the system at all, its like its recharging then pressure is lost so it starts recharging again whats the likely cause and how to fix the git or is it just low on gas so wont kick in ?

dojj

iTrader: (3)

what are you using to check the pressure?

it's supposed to go up and down on the gauge as the gas pressure changes as it heats/cools

the click should come from the compressor as the magnetic clutch kicks in and out to make sure it's working

your best bet is to ask forgien rs on here as he used to tinker with a/c for a few weeks about 20 years ago, he seems to remember some stuff

but basiclly there is the gas in the system, and a series of sensors to make sure the pressure is right and the temprature is right and that's about it

the temp senser checks to see if the temp has been reached and thenit turns the systm off until the higher temp is recorded, then it turns it on again

the pressure one doens't allow it to turn on if there isn't enough pressure

the compressor may have had it though as they can wear out which may expalian why it's struggling to send the gas around the system even though the clutch is engaged

open the bonnet and see what's happening to the front pulley on the compressor, it should stop and start as it's kicking in and out

STeve

iTrader: (11)

cheers Dojj I will fire it up tomorrow and have a another test and youtube it,

STeve

iTrader: (11)

pump is way underneath and impossible to really see unless in the air, video is shite quality but you can see and hear my issue, any help from those in the know ?

dojj

iTrader: (3)

i would say that the pump is pressuring the system too much and then it's kicking out again

not sure what could cause this as it could be a blockage, the pump being fubar, not enough oil in the system, a sensor, or anything else

the proper gauges have 2 gauges to measure 2 different things from the 2 different connectors so perhaps you could try to connect it to the lower/high pressure side and see if that's any different?

not sure if they have the same fittings though

stevos

It's low on gas mate its going off when the pressure get to zero as they have pressure switches to stop them going into a vacuum and causing moisture contamination in the system.
I would be pressure testing the system for leaks.

STeve

iTrader: (11)

nice one mate thanks for the heads up as I will give it a try

stevos

If you were near me I would have had a look for you no probs.

Glenn_

iTrader: (1)

The fiesta takes 750g of gas according to the sticker under the bonnet.There must be a bit of gas in the system cause if there wasnt any the ac pump wouldnt kick in.

dojj

iTrader: (3)

Didn't you recently regard it at kwikfit steve?

Probably a leak then if its now stopped working

STeve

iTrader: (11)

Thats was my daughters fez dojj that was regassed. The clicking threw my off as i did not know if it was a fault or just low on gas as hers did not click even when low

stevos

The gas charge must have been really low in hers as there wasn't enough pressure in the system to activate the pressure switch.

Glenn_

iTrader: (1)

Causing the pump not to work.

STeve

iTrader: (11)

Top info chaps and glad I asked now as this info may help others too

stevos

Yep glen 100% rite the lp switch is wired in series so if its an lp fault the compressor won't run

dojj

iTrader: (3)

but it could be tripping out on hp as well if the pump is kicking in and out like that as well

much less likely, but if it's got gas in it and the system is blocked it could be the case

STeve

iTrader: (11)

I will have to use my halfords card and buy a can of r134a and see what pans out

stevos

If the system was blocked the back pressure wouldn't rise and fall mate. A choke in the system would cause the guage to drop and stay low. As the refrigerant would be able to pass through the blockage. Think I'm explaining this rite am a bit pissec and its commercial refrigeration I deal in but the principles are the same.

Glenn_

iTrader: (1)

How much are these cans and how much do you get in them.

STeve

iTrader: (11)

they are large can in halfords for £34, but you get £10 refunded when you take the empty can back and if you have a halfords trade card you get around £6 further off too

steve.rst

I agree with stevos, it does look like its low on refrigerant, you should repair the leak first before recharging with r134a.
stevos, i see your a commercial refrigeration engineer aswell, doesnt it pee you off that we have to do a 3 day F-gas course (costing £700 +) just so we can recharge refrigerants into a commercial fridge system, but anyone can go into halfords and recharge the car aircons without having to do any course at all.

stevos

Yep mate it kind of does. The company I work with we need to account for every gram of refrigerant we use. But jo public can just go in and buy a can and top up there ac even if its got a leak. We are not allowed to put any refrigerant into a system without first finding a leak.

Mickeystewart

if your local to kent I can sort this for you.

I have all the corect equipment, Nitrogen to pressure test and find leak, Vac pump and refrigerant, let me know if II can help

foreigneRS

the 2 steves are dead right

yeah, but a car system holds around 1kg, and a commercial system could be many times that.

Brendan

iTrader: (1)

I have a BMW and apparently they will leak out over a few years (3) if you don't use it regularly! If you do use the a/c the are of leaking is vastly reduced. The chap said it is to to with the design of the pump!

Any idea's what this could be?

Also might be worth pitting in a UV fluorescing dye into the system so you can spot any leaks more easily!

foreigneRS

the pump, which is not a pump, it is a compressor, is mechanically driven by the engine. there is a shaft from the external drive to the internal components which needs to be sealed to prevent the refrigerant from leaking out.

that shaft seal is a ring of rubber around the shaft and relies on regular use to remain lubricated and pliant. the lubricant is within the compressor body and is carried around the system by the refrigerant and if the a/c is not used it will just sit in the crankcase of the compressor and not lubricate all around the shaft and the seal.

there are other valves and actuators in the system that should have regular use.

timster

I've just had my aircon regassed on my mondeo,but its causing the car to run irattically and change the engine speed by a few hundred rpm when cruising along. Is the compressor knackered? Is there anything I can do to free it off?

foreigneRS

it's normal. ford were cheap skates and buy fixed displacement compressors that have to cycle on and off and put quite a load on the engine that you are noticing. the alternative of variable displacement compressors that remain on at (virtually) all times but just change their displacement to meet the cooling load are obviously more complex and expensive.

and Brendan, you are welcome. i'm glad that i took the time to type that reply for you

timster

Thanks for the reply Nick

STeve

iTrader: (11)

Just to update my original querie, as mentioned by the PF gurus the system was simply low on gas so a can of gas and £17 later using my halfords trade card its now ice cold and the clicking sound has stopped

stevos

Good news mate I just re gassed my van there as well.
Total cost £0 is I carry r134a.

Brendan

iTrader: (1)

Thanks for the info on the BMW pump! how often di you think I should use it to make sure it is correctly lubed up?