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I already know the first response will be "take it to a garage" so please, just let me know if you have experience with the DIY method.
The air con in my better half's Fiat Panda is dead. The local garage has already relieved her of £75 for a recharge when it's got a blatant leak. It worked for a few days and now nothing. And we're driving to Europe at the end of July so it's essential I get it fixed.
The hard part is finding the leak. This is why the garage guesstimated 400 to 500 quid for a proper fix. I know where all the components are and there's a loud hissing sound from behind the dashboard which wasn't there before. I know the process is simple it's just time consuming.
My time is free so I don't mind if I have to fully dismantle the car to fix it. I absolutely refuse to drive through France and Italy in a puddle of sweat!
So my question is, has anyone used any of the available hardware? Refrigerant with UV dye in it? Refrigerant with leak sealant in it? Any particular kind of hose? The stuff on the Halfords website has pretty terrible reviews.
It's all available on ebay and amazon but I don't want to buy stuff that doesn't work. Any tips on methods, techniques etc, all welcome.
If your system has been that badly you will end up with air and moisture inside the system.
The system will need to be under vacuum to remove the moisture before recharging (once the leaks have been resolved obviously)
Unless you have a vacuum pump and all of the gear I would suggest going to Kwik-Fit as I'm sure they wont charge you if they do a refill and find a leak.
So....
Take it to a garage..
Have used the halfords cans. They're 5h1t. I ended up taking it to kwik fit, getting them to inject it with uv dye, looked for the dye in their bay, gone home, replaced the faulty pipe and used their free recharge service to get it topped up again. Environmentally a disaster, but very cost effective. Wouldn't dare use a leak sealer. Surely the function of the evaporator depends on a leak in a pipe inside the sealed system.
Note: all the fittings are schraeder so you can put dye in but no refrigerant and use a shock pump to pressurise the system and trace the leak. Just don't start it up until you've had it drained and recharged properly as the lack of fluid will shag the compressor.
What they should have done is add a UV dye when hey filled it to trace any leaks. The chances are it is just a deal or a cracked pipe but could be something a bit pricier.
One of my concerns is noise from behind the dash. It wasn't there before and now it's very audible. If that's where the leak is it'll be a full dashboard out job and that will cost a fortune at a garage.
I honestly don't mind doing it myself. The compressor and all the schraeder valves are easily accessible. I just didn't want to waste money on crap tools/refrigerant etc.
For example, all the hoses look like this- LINK
But is that a decent bit of kit, or mickey mouse?
You need to have the leak identified as stated in posts above , once the component is identified replace , and get the system tested/refilled , replacing some components requires additional oil to be added to the system - this is usually described in workshop manuals.
I have a vac pump and AC manifold , that I have used to test a couple of systems after replacement of older car A?C components - before sending them to get refilled , the gas and certification cost a lot these days so not worth it for diy, I have not worked on systems that already have gas in them as that is where you need the equipment to de-gas and that is not diy viable.
I have replaced holed condenser, and A/C pump on another , need right oil , green O rings , then put system under a vacuum and let it sit for an hour to see if it holds.
The biggest problem you might have is replacing what sounds like the heater/a/c matrix in a panda,
quick google suggests that this is quite a major job , if you are lucky its a pipe you can get to and replace. (major as in even having to take the doors off ..)
OK in your link is a hose/guage to fill and measure but you really need a manifold and pump like this :
I can borrow a vacuum pump. I've just been reading all kinds of guides. It sounds no harder than like bleeding brakes.
What I need asap is a way of getting some UV dye into the system.
EDIT: Actually, for that price I might just buy the kit and set up a little weekend sideline! Anyone need their air con servicing?
Did they not add the dye when they charged it.
We used to gas and dye at the same time.
You can buy the dye in a litre bottle that a syringe and a shock pump might get you there
My concern would be making sure the systems dry when finished so you don't damage the compressor
you need gas/oil/dye in the system for it to pressurise and leak, you can get the system under a vacuum with the pump/manifold and then add dye , but adding the gas is more tricky as you have to effectively discharge that gas into the environment via the known leak , hence I would always have the leak diagnosed first , do the donkey work myself , test the vacuum and then get it filled with oil/gas by a proper machine.
Fix the leak yourself and have a garage fill it up properly once your done.
Can you find one in a breakers yard to scavenge from ? If the noise is coming from behind the dash it’s likely the evaporator or the pipes leading to it.
I’ve pulled the dash on a couple of Fiat Puntos to swap the heater matrix over. It’s not that hard if you’re methodical.
The hissing could just be because the gas is low, and not the leak. I've had to fix various vehicles where the evaporator has been hissing, and it's just been because the gas is low. The fault is far more likely to be the condenser, or a pipe. Check for any oily damp patches on the condensor.
Any reputable place should of added dye as part of the recharge, and at least had a quick check over with a sniffer for any obvious leaks.
TBH, the two times my A/C failed, we tested with dye in the system. First was the air con radiation - had been holed by road debris (£400), the next time an alloy pipe had sheared at the pump - unfortunately the ruddy pipe was a one piece unit that ran to the back of the engine bay, another £400. That said, it's wear and tear - that's the only issues I've had with my a/c on the car and it's 17 years old.
These two videos cover everything I need to know I think,
https://www.youtube.com/watch?v=Pdq8JAlct6s
Looks easy! And once you've got the tools, you'll enjoy freezing cold AC for life.
Right. Forget about the air con gas/ refrigerant for now, firstly you need to fix the leak.
To start with the leak needs to be identified, a UV dye injected into the system when the system was last re gassed will be visible as a fluro green, a UV light will make it easier to spot.
However if what is leaking is obscured such as the evaporator (the thing that gets cold and the air blows through, located in the dash) or the condenser (like a radiator, located at the front of the car sandwiched behind/infront of the actual radiator.) You won’t be able to see the leak.
The best way is to use nitrogen to pressurise the system and then identify the leak, spraying soapy water if it’s in a visible area to see bubbles will help confirm the leak’s location. A car garage can pressurise with nitrogen for not a lot of money or if you can find a way yourself to use compressed air that will achieve the same thing.
Leak found, you will need to replace the leaking component, but also the receiver dryer canister as it is full of a moisture absorbing material, that when there is a leak moisture from the outside world gets in and oversaturates the absorbent material making it ineffective, so after you re gas the system, any moisture will not be absorbed in the system.
After a proper car garage will test the system for leaks with nitrogen then vacuum the system again removing any moisture and air from the system, then hold vacuum pressure for 10 minutes to check for leaks, then fill with refrigerant to a measured amount set by the manufacturer.
A plug and squeeze halfords can is no good
Its a criminal offence to knowingly vent refrigerant to the atmosphere.
fix the leak first.
You need a black light UV lamp follow the lines, air con oil already has the dye in it,
Its probably the condenser leaking.
theres lots of one man band air con types that will help you find the leak, you can then swap new parts in yourself if you like and they will come back and refill it for you. It will be way way less than £500.
I've changed pipes, condensers and once a compressor on my cars,
Don't waste your money on cans of stuff from halfords.
Ok, so it’s actually against the law to recharge an AC system with the knowledge that it’s actually got a leak, UV dye should not be used, instead you should use Nitrogen test equipment, locate the leak and fix before any R134a is put in the system (assuming that’s the correct system).
Please don’t attempt to do a DIY fix as it won’t work, beyond a couple of days or so.
Interested in this thread as dr nosh jnr #1 has an a/c system that does not blow cold in his Renault.
I'm a mech eng with a workshop full of bike/m.cycle/car tools.
Tackle most car jobs.
If I pressurise the system off my compressor and use soapy water to search for any leak, what air pressure should I need to achieve?
For legal purposes, a vacuum test is adequate prior to refilling an AC system. The law just states the system must be leak tested prior to gassing, it doesn't stipulate how it's tested.
Although chances are most systems will pass a vacuum test, then start leaking once pressurised as the pressure blows out whatever was sealing the leak, however as you've conducted a leak test, if it does leak after gassing, you've not done anything illegal.
@drnosh - https://www.quora.com/Why-do-technicians-use-dry-nitrogen-instead-of-normal-air-to-test-pipes
Using air is not recommended (yeah, I had to google why, as it's been about 10 years since I done my AC training!). Pressure wise, you normally just ramp up until you either hear the leak, or until you know there is enough gas flowing that you should be able to detect it. AC systems are generally good for 15-20 bar though, which is higher than your typical air compressor can manage.
Seriously, thanks for all the tech info.
Firstly though, I have no intention of pumping refrigerant into the atmosphere. I know for a fact there's a leak.
I already have a UV light and I was thinking about using a shock pump to insert the dye into the low pressure pipe. I've already tried pumping and squirting with some alcohol and it worked fine.
The dye though is bloody expensive! It's 5 or 6 quid for a tiny 5ml bottle and I assume I'll need more than one.
I can borrow a vacuum pump from work (from someone who vacuum bags carbon fibre parts) so I can fully purge the system afterwards.
All I really need is the manifold/gauge system. These vary wildly in price. I don't mind buying a decent one as I'll no doubt be using it again.
We had around thirty Ac units fitted to one of our buildings and the guys tested them with air rather than nitrogen. Every single one failed with the first year!
For legal purposes, a vacuum test is adequate prior to refilling an AC system. The law just states the system must be leak tested prior to gassing, it doesn’t stipulate how it’s tested.
But drawing a vacuum is a leak test. Primarily the purpose of drawing a vacuum is to dry the system out as you don't want any moisture in there. Clearly if there is a leak in the system then a vacuum probably won't be held so it can indicate there is a leak but won't indicate where so it is not an effective leak detection method in its own right. Some leaks are apparent when the system is pressurised...under a vacuum the leak might be sealed and holds a vacuum fine, but as soon as you pressurise the system the leak is there.
You have to do a proper leak check using a dye or nitrogen. But how do you know its got a leak?? You say its got a 'blatant' leak...what do you mean? Just because the system has stopped working doesn't mean its got a leak.