Air-Con Re-Charge:

[BobMurphy]

I have a 2001 Auto Amazon 4.2 24 valve Td 'VX'; it has climate pack and air-con, rear heater but not rear air-con.

I took it to a friend who has a Garage business and asked him to re-charge the air-con. His little book lists the amount of gas required for a vast range of vehicles but under the '4.2 Amazon' it says - "refer to label under bonnet or under compressor pump".

There are two stickers, both relating to the type of refrigerant to use but there is nothing about volume.

He wouldn't touch it .

Does anyone know how much fluid/gas these things take ??

I should have known it wouldn't be a simple job .

Bob.

 

[SteveJB]

Strange had mine done last week and the garage just got on and sorted it no ifs buts or maybes said it would be about an hour or so put 134 in it and 65 quids plus the nasty and 78 quids later was driving home in a hat coat and scarf dont think volume matters just confidence to do the job

 

[chapel gate]

I always thought it was to the correct pressure rather than volume Bob.

 

[BobMurphy]

I always thought it was to the correct pressure rather than volume Bob.

Its pressure if you are just topping-up from a Halfords bottle.

The fancy machine at the garage drains the system then injects various stuff - including lubricant - before pressurising. I don't know a lot about it but Andrew was worried about the consequences of over-filling it.

Life just gets too complicated sometimes and I'd rather leave it to others . . But then they take fright and I have to do it myself !

Bob.

 

[BobMurphy]

said it would be about an hour or so put 134 in it and 65 quids plus the nasty and 78 quids later was driving home

What does "134" relate to - P.S.I. ??, CCs, you can tell I'm confused.

Bob.

 

[SteveJB]

HFC134a refridgerent Oil is ND OIL 8 this should be on a sticker on the slam panel just to the left of the rad cap PSI is pounds sqaure inch CCs is cubic centimeters as 4.2 cc

 

[BobMurphy]

DOH ! I should have spotted that connection . . . Of course .

This pm I had another go at re-charging the air-con with top-up bottles. I haven't had much success in the past, probably because I thought it was a quick process - which it patently isn't.

Half an hour of bottle shaking and warming later the pressure gauge is showing 27 psi and its blowing cold. Static pressure is 45 psi which is at the top of the 'charged' sector on the scale.

Hopefully that will do for now.

I would like it to be professionally cleaned-out and re-filled sometime.

Bob.
Still no wiser . . . But better informed.

 

[StarCruiser]

Bob, somewhere on the high pressure side (small bare pipe work) you should find a sight glass if it’s anything like the 80. Look in it with the engine running and the AC on with a torch and look for bubbles in the refrigerant. If it constantly runs clear and blows cold you’ve got enough gas in it. If you can see bubbles, it’s short of gas. If it’s clear and not getting very cold then it’s nearly empty.

I’m not sure about pressures but it’s not correct to fill to pressures really, to recharge from scratch the refrigerant should be weighed in.

As long as there’s been no air, moisture or solid contaminants allowed to enter the system, and it’s running fine, then there is no merit whatsoever in emptying the system and refilling it. Bear in mind that R134a is around the £90 a kilo mark now and you have no idea how much oil is in the system.

You can’t beat using a proper refrigeration engineer to top up and leak check the system.
As for how much weight of refrigerant should be admitted, I would think an 80 series won’t be far off. Overfilling causes the engine to labour and there’s usually a blow off valve if things get really high so it’s no big deal but worth doing right. Oh, wear goggles, if you squirt refrigerant in your eye it’ll freeze the eyeball. Not nice!

 

[GeekOKent]

I was looking around to see if I could get the gas sorted in the 105, and it looks like Mr T does this refresh and regas for about £50

Might just go there. Given the bottles of has are about the same price

 

[frank rabbets]

I would go to toyota for that quote. Ask them to add dye and check for leaks after they've filled the system.

 

[StarCruiser]

I’d just ask them to leak check it. Dye doesn’t show all leaks as it’s a larger molecule than the gas.
£50 is a good price for topping up the gas. All depends what exactly you get for your money.

 

[flint]

The place I went to pressurised the system with nitrogen first and then checked for leaks with a detector (it leaked !). A bit of info here (the refrigerant quantity is by weight in grams):
https://www.hella.com/techworld/au/.../Car-refrigerant-oil-filling-quantities-2114/

 

[StarCruiser]

The place I went to pressurised the system with nitrogen first and then checked for leaks with a detector (it leaked !). A bit of info here (the refrigerant quantity is by weight in grams):
https://www.hella.com/techworld/au/.../Car-refrigerant-oil-filling-quantities-2114/

This is exactly what is needed. A little puff of 134a and pressurise with nitrogen. Then go around with a leak checker.

 

[Towpack]

Ive had mine done in the past by Kwik Fit. They just connect up a machine, tell it the make/model of the vehicle and it does the rest. Remove old gas, vacuum test then refill with gas/lube mix. They are charging £60. The last recharge I had done was around 3 years ago by a local specialist after I replaced a leaking condenser (for the third time) and dryer unit. Its still working to full effect and is the longest its ever gone without a recharge.
The first two condensers failed due to corrosion at the joints between the core matrix and the end tanks. I gave the last one a good coat of engine enamel paint making sure the joints were well protected.

 

[frank rabbets]

As an aside there is no way anyone can tell how much oil is in the system. Some say the machine "knows" but it does not. The machine weighs how much oil comes out during vac and replaces that amount with new but it cannot get anything like all the oil out. Every time you replace a component or have a leak oil is lost. The amount you should add back is listed in the FWSM for each item but there is no guide for leaks. I learned the hard way with my pump bearings wearing out. In fact there was just oil vapour really. I knew this because I took everything off even pipes and drained them.....nothing !! What amazes me is how much the kwik-fit etc techs actually know. Usually zero. And there's precious little on the net. Thanks to Richard and Dave on the forum I now know almost everything about the 80 system.

After I had filled my empty/dry rebuilt system with 8 ounces of oil only 1 ounce came out during the vac.

 

[Towpack]

As with engines there’ll be a dry fill and a wet fill capacity. The amount of oil you use in an oil and filter change will always be less than an initial fill on a “dry” engine. Ditto the AC system.
The fully auto machines now being used to recharge aircon systems don’t need aircon experts to use them. Connect up two hoses, switch on, press a few buttons and that’s it. The AC system is not that complex anyway, just a few pipes a rad and a pump, akin to a cooling system only much higher pressure. It’s only when you have a particularly troublesome AC problem, especially an intermittent one, that you need the expertise, experience and test equipment of a specialist. JMO

 

[frank rabbets]

The total oil capacity is 8 ounces. Once it is put in that's it. There are no dry fill or wet fill options. The machines are automatic but that does not mean they can do much and only measure the oil taken out "by accident".

 

[Towpack]

The auto filling machines don’t measure the oil taken out. They just remove all the gas to a vacuum and refill with a given gas volume with a measured amount of oil added and, on a sound AC system, they work perfectly. When I had mine refilled by a local AC shop, who also had a similar machine, ( I only went to him as he had an offer on to be honest) and I told him of the new condenser and dryer unit he added more oil than if it had been a straight discharge/recharge.

 

[frank rabbets]

When I watched my brother's machine it evacuated the gas and in doing so it inevitably removed some oil. This I could see going into a plastic bottle. The machine weighed this oil and added back that amount of new uncontaminated oil. Now that assumed I had a full system, which I had. There was an option to add more oil in the event some parts of the system having been replaced. My MOT man, a friend, has a different make of machine but weighs removed oil. Now there may be machines that don't weigh oil removed during vac but then they would not know how much to add back as inevitably vac removes oil.

 

[Towpack]

Looking at how AC systems are recharged wether it be from a fully auto machine or manually I get the impression that oil amount isn’t that critical, rather there’ll be a max and minimum figure, much like the max and min marks on an engine oil dipstick but on a smaller scale. Too little will obviously wreck the compressor, not sure what effect too much would have. Possibly reduced cooling capacity or some other form of compressor damage, hydraulic lock maybe?