Aircon Regas

[RJC]

I guess it's a similar concept to topping up your engine oil, sure it will be below the minimum mark on the dipstick, but the car still runs fine, although it's not a good idea, as it may affect the efficiency of the engine, if the air conditioner hasn't got the right amount of refridgerant, then surely there must be something else in there instead, (air?) the compressor will try to compress air and there will be air floating around the system surely? That should therefore mean the compressor is working harder?

The space will be occupied by vapour basicaly, as the the refrigerant leaks out out, less liquid is produced and you end up with flash gas (liquid vapour mix) going to the evaporator which means amount of heat being removed from the medium is reduced.
Only time air gets into the system if the charge has completely escaped or the low side has a leak the charge is low and a vacuum is formed then the air will get sucked in.
Lower the charge less stress on the engine as there is more space in the condenser to condense the vapour which means lower head pressures and less stress on the engine!

Rob

 

[Lead_Head]

What causes the eggy smell on air con? Mines recently very smelly

 

[OllyM]

What causes the eggy smell on air con? Mines recently very smelly

Bacteria in the system - do you not use it very often?

 

[Kappa]

Quick question, I always have the CC on at 20 Degrees, come rain or shine. Bad? Does heating use the AC? I always thought it did

 

[[TW]Fox]

I guess it's a similar concept to topping up your engine oil

It's actually not, which is why there is no dipstick or way of measuring whats in the system without the use of a professional.

 

[OllyM]

Your climate control should have an AC on/off button - on the BMW it's a ********* button that runs the aircon when pressed. If you don't turn it off it should be running and keeping the system working properly.

 

[Scottland]

What causes the eggy smell on air con? Mines recently very smelly

Mine's more a metallic smell but yes I believe it's some sort of bacteria build up that causes it. You can buy can's from Halfords that clean it, but I've never used one so I don't know how well they work.

 

[lordrobs]

Is there something wrong with your aircon then - 3 years and its all gone already?

I've never had to have a regas and none of my cars have been regassed since new. The Mondeo for example is now what, 8 years old and still blows as cold as it did the day I bought it at 4 years old.

Isn't the replacement of the lubrication of the aircon system carried out as part of the re-gas too? Thats the reason that mine is getting done at 4 years whether its still blowing cold or not. On my Octy it was done after 2 years but mainly because the previous owner was super anal and worked under the principle of look at the service interval then halve it

 

[[TW]Fox]

Once the gas drops below a suitable level, the condenser will no longer engage. This itself is usually far after it stops being ice cold - until it stops blowing nice and ice cold there is plenty of gas left in the system.

 

[lordrobs]

Once the gas drops below a suitable level, the condenser will no longer engage. This itself is usually far after it stops being ice cold - until it stops blowing nice and ice cold there is plenty of gas left in the system.

Not disputing that but the point I was trying to make is that isn't it possible that after 5 years or so there is still plenty of gas but no oil left in the system?

I'm no expert on this at all, just going on what I've heard.

 

[Clarkey]

It's actually not, which is why there is no dipstick or way of measuring whats in the system without the use of a professional.

Actually there is, there will be an inspection glass in a refrigerant line. If you see bubbles passing by then you have problems.

Well, not a way of measuring, but at least a form of inspection.

 

[Kappa]

Actually there is, there will be an inspection glass in a refrigerant line. If you see bubbles passing by then you have problems.

Well, not a way of measuring, but at least a form of inspection.

Where abouts would it be? Most of the stuff in the Passat is covered in plastic

 

[RJC]

Not disputing that but the point I was trying to make is that isn't it possible that after 5 years or so there is still plenty of gas but no oil left in the system?

I'm no expert on this at all, just going on what I've heard.

The Oil in a car A/C system is carried with the refrigerant, if you leak oil then you will leak refrigerant.
Amount of oil in a car A/C system is very minimal.

Actually there is, there will be an inspection glass in a refrigerant line. If you see bubbles passing by then you have problems.

Well, not a way of measuring, but at least a form of inspection.

There usualy a sight glass in the liquid line leaving the condenser, but not all models have them.

Rob

 

[blueboy2001]

Once the gas drops below a suitable level, the condenser will no longer engage. This itself is usually far after it stops being ice cold - until it stops blowing nice and ice cold there is plenty of gas left in the system.

I think you mean compressor - the condensor is just a radiator really.

An aircon system has a optimum amount of refrigerant for best performance. The compressor is controlled by high and low pressure switches.* As the refrigerant level drops there is less refrigerant for the compressor to compress and so it reaches the high pressure level much quicker. A lower volume of refrigerant in the system will allow the pressure to drop back down quicker than if the system was fully charged.

Your air can still be ice cold, but your compressor will be cycling more frequently and the off cycle time will be shorter so the compressor is working itself harder.

*Some cars use variable displacement compressors that can vary the level of compression rather than simply being on or off.

There's no real timescale for a regas - it depends how well the system is designed and built, how often the AC is used etc. Leaving it until the air is no longer cold is really too long.

 

[OllyM]

Leaving it until the air is no longer cold is really too long.

Thank you!

Fox, I'm surprised you seem so anti getting your aircon regassed, for the trivial expense, you could be prolonging the life of your air conditioning system

 

[branddaly]

Thats a decent price, most places are closer to ~£100

I had Kwik Fit do my Mondy last year, and that was only £40, their website presently advertises it as £45.

However my Air-con was back to warm, so I purchased a re-gas can from Halfords. 10 second job and my air-con is back to cold, plus there's more in the can to top it up again if needed. Unless it all leaks out again in the next few months I'm not likely to pay for the aircon system to be overhauled, the cars too old for me to pump money into it.

 

[austinpowers]

I just added gas to mine using a those small cans, comes with oil added as well.

Even has a little gauge to let you know how much pressure there is in the system, should be around 40psi on the low side.

I bought some manifold gauges the other day, so i can check my low and high sides, adding gas is simple, R134a for post 96 cars, R12 for pre 96 (which is not commercially available anymore) or R12 subsitute which is what i used.

The aircon system in a car is not that complicated, uses different gas compared to a say a fridge (R22 which runs at higher pressure) but if you break the components down and think about it, a competent diyer can re-gas and keep on top of most issues.

The hardest part to remove or service is the evaporator inside the car, fiddly thing to get out

 

[[TW]Fox]

You can guarantee that if it were as you guys say it is there would be an 'aircon service' built into the service schedule becuase:

a) It prevents breakdown which affects the image of the car, especially a premium car

but more importantly...

b) It's something else to get Mr Average into the dealership for to charge him a small fortune for his main dealer stamp and stiff him for extra work.

Yet we've got people with 10 year old aircon systems working perfectly and no way of checking how much gas you've got yet you guys still think it should be a good idea to spend money regassing an otherwise perfectly functional air conditiong system? You change your tyres at 6mm as well?

 

[Tom|Nbk]

Well it's been a coldish day today so this evening I made sure I checked the air con. The air coming out does seem pretty cold if you put your hand right up to the vent but it doesn't seem as effective in cooling my car. I can leave it on and it won't make me so cold that I'll have to turn it off, it just feels slightly cooler than opening my windows.

I'm not sure really I'll get it looked at and see whether the temperature is within acceptable thresholds, it doesn't feel as tight as when I first got the car almost 2 years ago mind.

 

[[TW]Fox]

Well it's been a coldish day today so this evening I made sure I checked the air con. The air coming out does seem pretty cold if you put your hand right up to the vent but it doesn't seem as effective in cooling my car. I can leave it on and it won't make me so cold that I'll have to turn it off.

If you get the feeling that it isn't effective then clearly the time is right to regas the system.