The A/C in my 2015 Citigo no longer blows cold.

The pump seems to be turning, so I'm guessing the refrigerant needs topped up.

Has anyone done this themselves?

I see bottles of the stuff on Amazon, and the hose to connect them to the car — not too expensive.

Thanks for any info.

I'd recommend getting it done professionally, least that way if you have a leak you won't be wasting your money on gas.

Dont be tempted, I started out that way before investing in the correct kit at considerable expense (manifold gauge set, vacuum pump, R134a cylinder, weight scale) and am still learning 4 years later and still have a lot more to spend.

 

Most of the supposed R134a disposable canisters are in fact "R134a Substitute" if you look carefully and are no more than butane gas, definitely not something to be added to your existing refrigerant and even if it were the right stuff (but how would you know?) you have no way of knowing if you have the correct weight of refrigerant in the system.

 

With my kit I used to judge the correct amount by the high and low side gauge readings corrected for temperature and humidity but it is in no way good enough, I risked having significantly too much or too little refrigerant in the system both of which have bad consequences.

 

Contrary to what I have written in the past the only correct way to refill is a complete system evacuation and refill by weight, the stages and the reasons why are explained below.

 

Test system pressure, if none then proceed to vacuum test and then hold full vacuum for an hour to remove any water vapour which may have got in.

 

If system does not hold vacuum with pump off and valve closed then abandon procedure or go to Nitrogen pressure test and use a spray foam leak detector to find leak.

 

If the system has pressure then remove the refrigerant gas using a transfer pump and transfer cylinder.

 

Then pressure test with Nitrogen to full high side system pressure, a vacuum test will not necessarily reveal pressure leaks and is at minus 1 bar, the nitrogen test will be at 18 bar positive, 26 bar on my home AC system.

 

If pressure test OK (valve closed and no pressure drop over 20 minutes) then pull vacuum again and proceed to gas recharge.

 

Connect R134a cylinder to manifold set and then purge connection pipe of air. Cylinder must be on weigh scale that has no cut out timer (so cheap ones are no good) and set to zero Tare.

 

Open valve and commence charging with cylinder upright, inverted filling risks fluid locking the AC pump (dont ask me how I know 😒)

 

Release valve and allow one third of the charge weight (probably 525g whole charge) to enter the system, initially it will flow quickly due to the vacuum.

 

Start engine and observe high and low side gauges when compressor cuts in.

 

Cease charging when the cylinder has discharged the correct weight.

 

Check high and low side pressures against chart corrected for temperature and humidity.

 

Check temperature of cold air from face vents on maximum cooling.

Edited 15 July, 20241 yr by J.R.

What sort of temps would you say is good after regas? I've had cars anywhere from 9C to 2C. Obviously ambient temperature effects that. Is ambient -10C ok?

Temperature measured where?

 

At the air vents or the evaporator temp sensor reading from VCDS?

 

Ambient minus 10° c at the vents when we had 43° here in 2002 wont please many!

 

Air vent temps may be corrupted by sticking airflow flaps, when ambient temps have been around 20° C I have observed the evaporator temp drop to 2°c but after 20 minutes or so.

 

I trust the gauge readings and the law of conservation of energy over anything else!

Edited 15 July, 20241 yr by J.R.

26 minutes ago, J.R. said:

Dont be tempted,

Thanks for that detailed reply. Seeing what's involved to do it properly, I don't think I'll try it myself. Cheers.

Temp measurement at the drivers vent open with all vents closed and recirculation on. Is that the best way to measure the coolest temperature? I'm using a probe no VCDS. Just talking about general checks. How long should you have to wait for temperature to stabilise?

Yes, the best way for the lowest reading unless the car has been standing in direct sunlight.

 

On recirc the temperature will continue dropping until either the AC can no longer overcome the radiant heat  gain or the evaporator temp drops below IIRC minus 4°c.

 

A couple of minutes should be enough to get a sensible reading, garages dont waste much time waiting. 

It's just when I am preparing cars for sale. I've noticed a lot of EVs have higher temps, not sure if they need driving for a bit first or just need recharge.

In theory, well according to my thought process, an EV should never need recharging like an IC engine AC system does and should run forever without losing refrigerant charge as a fridge or home AC system does.

 

Why? Well lets take a look at where regfrigerant loss occurs, other than a perforation of the condensor etc it is through the polymer walls of the flexible hoses and to a lesser extent through the O rings on couplings.

 

A refrigerator has solid non flexible copper lines joined by silver soldering, split AC units used precision flared joints between the copper liason tubes, these done correctly do not leak, the exception being the DIY ones with pre-charged lines and dry break connectors which have O ring seals, they have a design life of 3 years, just beyond any warranty offered and nobody will touch them when they stop working.

 

An EV does not have an engine driven compressor needing flexible hoses, I reckon they have a similar set up to a home AC unit with flared joints in the refrigerant lines.

 

Never having clapped eyes on one I await being disabused of my notion!

Edited 16 July, 20241 yr by J.R.

Ev definitely have flexible/rubber hoses. Running under and around the car to cool battery etc.

24 minutes ago, Blue8793841 said:

Ev definitely have flexible/rubber hoses. Running under and around the car to cool battery etc.

 

They will probably have them on the condenser as well. Most EV's will have a heat pump setup rather than just straight AC as well as it is more efficient for heating the cabin. It wouldnt surprise me if the more budget EV's don't have as good as an AC system purely to reduce load on the battery as well, or maybe they are set up so when the car is stationary the AC output is less.

 

I second what J.R has said though, with some experience and trial and error you can get the charge something like good using a set of gauges, enough to be able to get good cooling and enough to get used cars out of the door, whether this is morally right is another question.

 

My Dad has had lots of good success keeping more 'mature' cars chilling nice but for a car you use a lot where you want the best performance get it charged by weight in the proper manor. Also remember the newer models won't use the usual R134A and may use R1234YF or whatever it is

AC in EV's also have a different oil/lubricant in the system.

 

Thanks. AG Falco

56 minutes ago, Blue8793841 said:

Ev definitely have flexible/rubber hoses. Running under and around the car to cool battery etc.

 

But they are carrying chilled air and not refrigerant gas which permeates the hoses unless they cost 4 figures a pop like they have to use in places like BOC, I first learned of it from a friend who worked there, he said one O ring of the superduper stuff cost more than an entire vehicle AC system.

 

19 minutes ago, SuperbTWM said:

They will probably have them on the condenser as well.

 

I'm sure you are right, there are lots of vibrations and harmonics at play when a vehicle is travelling at highway speeds compared to a fridge or outside AC unit although both of those sit on rubber isolation mounts and move relative to the fixed pipework, different frequencies and amplitudes though and not to forget if the driver decides that his Tesla is the General Lee - yeehahh  😛

 

19 minutes ago, SuperbTWM said:

I second what J.R has said though, with some experience and trial and error you can get the charge something like good using a set of gauges, enough to be able to get good cooling and enough to get used cars out of the door

 

Absolutely, its what I have done to date but the performance is a little down, the guage readings not quite right, when my scales finally arrive I am going to do it properly meaning sacrificing the gas that is already in there.

 

My neighbour installs domestic AC and heat pumps, properly trained and qualified as France insists but also very practical like myself, he has taught me a lot, when we commissioned my home AC 2 weeks ago in theory we should have added 60g of refrigerant for the 3m over the nominal 7m pipe length but as he said without evacuating the system and weighing the gas how did I know it contained what they claimed, he works on the pre-charge being good for 10m and goes by his experienced ear and the sound of the pump to decide if it is over or under the optimum charge for the pipe(s) length

 

I'm sure a mechanic with experience of regassing systems would be able to work the same way, when I used to have Freon regasses by Fred in a sheds they all worked that way, these days however its an automated money making machine in a Fast-Fit centre, they just connect it up and leave it to do its stuff, most of them have no clue on how the system actually works or the first principals.

Edited 16 July, 20241 yr by J.R.

The master tech at work won't let us use his AC machine, unless he's on holiday it gets used 🤫

1 hour ago, J.R. said:

 

But they are carrying chilled air and not refrigerant gas which permeates the hoses unless they cost 4 figures a pop like they have to use in places like BOC, I first learned of it from a friend who worked there, he said one O ring of the superduper stuff cost more than an entire vehicle AC system.

 

To be honest, I think the common practice for battery heating/cooling is a seperate water circuit rather than using the AC or cool air directly, if you look at  a Telsa battery pack being removed you see the water connections.

 

1 hour ago, J.R. said:

 

They just connect it up and leave it to do its stuff, most of them have no clue on how the system actually works or the first principals.

It does make it an almost idiotproof procedure though and pretty well priced considering how much a can of 'top up' is.

44 minutes ago, Blue8793841 said:

The master tech at work won't let us use his AC machine, unless he's on holiday it gets used 🤫

Because he's done the a/c refilling course and you haven't. Which means that you're breaking the law and he isn't.

And all these years I have not taken a holiday because I thought it was against the law!

 

Joking aside, connecting and setting in motion an automated AC recharge unit does not require an F gas qualification, that is their USP, the operator does not manipulate the refrigerant gas at any time.

 

Removal of the recovery cylinder from the unit for recycling does even though it is no more complicated than changing a Calor gas bottle on a caravan.

 

 

Edited 17 July, 20241 yr by J.R.

BEV,s are a whole different kettle of fish.   Fitted with heat pumps or not.  Plenty bev,s can be pre heated or pre cooled before ever getting in the car. As to the interior temp of cars cooled down.  14*oC is really quite cool for many.   As to AC working and cooling an interior, it is a very different amount of cooling needing from 34 degrees C down  to 14 degrees,  compared to 24 down to 14.  And keeping that 20 degrees reduced temp.     @Blue8793841 what kind of dealership do you work in? And are people not trained on working on EV,s allowed to do work on them? 

Edited 17 July, 20241 yr by Ootohere

Don't do it yourself - first off, you probably have a leak from an old seal or pipe junction, or damage to the radiator, which is why you lost refrigerant. This needs checking before you blow more gases into the atmosphere. Second, you need to be sure you have the refrigerant/oil mix right. Third, you probably need a new desiccator to be fitted.

A lot of good points have already been made here, especially about leaks and why simple “top-ups” are often a waste of time and money.

One thing that often gets overlooked is that noticeable loss of cooling over a short period almost always means a leak rather than “normal” refrigerant loss. In practice it’s usually the condenser, ageing O-rings, service ports or the compressor shaft seal, and you’ll often see oily residue around the leak point because the refrigerant escapes together with oil.

I recently came across a fairly clear write-up that explains common leak causes, typical symptoms, how often systems really need recharging, and why running low on refrigerant can damage the compressor if it’s ignored. It also covers why DIY cans are risky without proper evacuation and charging by weight.

If anyone’s interested, the article is here:
https://refrigerant-euro.com/blog-en/car-ac-refrigerant-leak-causes-symptoms/

It pretty much reinforces what’s been said above — find and fix the leak first, then vacuum and recharge properly, otherwise you’re just delaying a bigger (and more expensive) failure.

When done properly the refrigerant usually also contains an ultra-violet sensitive dye (as well as the oil for the compressor) that can be used to help locate leaks.