Skoda A/C doesn't work in hot weather

Are the fan(s) behind the grille running ? they cool the condensor, that may be why it works at lower ambient temps. Most cars arrange for the radiator cooling fan and the condensor fan to be in series and run at half speed whilst the aircon is on.

Pete

Because the system is designed to produce air at a temperature of 5 degrees, so the warmer the ambient air temperature and the greater the difference, the harder the system has to work.

On everything except for a few Saabs* the compressor load is either on or off. What is variable is how long the compressor is used. In higher ambient air temperatures the compressor is used more than not. When it's cool and the system is engaged, the compressor may only be in use for say twenty percent of the time. When it's 35 degrees outside and you've just started the engine and air conditioning, chances are it'll be running for over 90% of the time.

Is the cooling system working as it should? Including the fan?

It is not climate control. Are you saying it is likely to have a temperature sensor in the system somewhere? If so, this could be where the fault lies. I have a workshop manual but the wiring diagram does not include the A/C.

It is not that it does not work very well at higher ambient tempertures - it does not work at all. When it does work it works very well.

As fa as I can tell everything is fine.

Climate control's air conditioning still squirts air conditioned air out at

The current Saab 9-3 is the only machine I am aware of with a variable rate compressor, rather than on or off, presumably this machine can output the air at a different temperature.

Absolutely yes.

It's possible that the temperature sensor is knackered and if this is the case it could be a simple part to switch. Surely, but surely, the diagnostics would have checked this rather than simply to replace the compressor, which as you say is expensive.

Do you hear the fan relay(s) clicking in, or the cooling fan, when you switch the system on? Do you hear the compressor running? Have you checked to see if the fan is running (don't wear a tie if you peer into the engine bay *cough*).

Errm Nationwide, that reknowned air conditioning company?

Benefit of the doubt and all that...

The air-con system does not cool the air to a set temperature. A properly sized and working system should be capable of lowering the temperature inside the car by about 15deg (I think- it's been a while since I checked that bit) below ambient. Inside the workshop, I'm looking for air coming out the vents at about 4-6degC with full recirc on.

There will be a air temp sensor, but not one that directly controls the air con as such. There will be a sensor to cut the aircon at cold temperatures (usually around 4degC), and possibly one to protect against over heating (but you'd still expect the air con to run for at least a short period)

If it's something like a switch faulty, chances are no faults would be stored. To find it, would require to have the system malfunctioning, while checking the datalist values for any obvious faults. And it's the getting it malfunctioning while having the diagnostic kit plugged in that's the hard part.

Not true. Ignoring systems with variable bits, the compressor will engage until a set pressure is reached on the high pressure side, then re-engage when the pressure drops below a set level.

Even without the fan working, I'd still expect some degree of cooling from the air con. From the symptoms, it sounds like something going open circuits when warm. Is the aircon clutch engaging when the air cons not working? It could be the clutch itself doesn't like running when hot (although I'd expect it to be faulty after running for a period of time), or one of the pressure or temp switched. I certainly wouldn't be getting the compressor changed for those symptoms.

A local garage charged me £570 to replace the knackered compressor on our 2001 Octavia, including the regas. If you're willing to buy in the compressor yourself, then you can probably knock a bit off that price too.

Shop around. (After making sure that it really is the compressor as others have pointed out).

Phil

It chills (conditions) the air leaving the vents, but not the cabin air temperature - that's what climate / climatronic / automatic / whatever it's called :) does.

Yes - that's the specification for everything I've seen and / or owned.

Aie that's what I meant.

My understanding isn't as technical as it should be - but when you run the interior fan at higher speed the compressor spends more time running than not. When it's warm out, ditto. Combine the two (hot day, engine start) and the compressor is on a lot of the time.

Yes - but if the car has been sat in the sun and it has an aggressive a/c shut off set up, one may not tell that it runs.

Me neither. It's one of the more expensive options, usually, it's the cheap stuff that fails. Usually...

On a standard air con system without any variable compressors/orifices, the compressor will run for the same amount of time regardless of outside temperature. The only thing that controls when the compressor cuts in/out, is the system pressure. Temperature does not affect it, unless it shuts down due to low outside temp when air con is not needed, and running it would likely lead to the evaporator icing up.

If it's a variable orifice system, then the compressor will run for longer, due to the variable orifice letting the gas through the evaporator quicker.

It may not be very effective when stationary or in slow moving traffic, but the air con should still work reasonably well when travelling at speed with a faulty fan. Plus if the fan was faulty, you'd most likely be experiencing engine overheating.

Still sounds to me like the system is being shutdown by some of the protection circuitry for some reason, but without somebody who knows what they're doing with diagnostic kit, finding the cause will be difficult.

A common problem on Fabias is sticking air flap motors.

I had a look yesterday to see if the radiator fan was coming on with the A/C. It was not. Out if interest I tried it with my elderly Passat and the fan did come on.

Whether the fan ever comes on I do not know.

-- Chris Melluish

Perhaps the system thinks the temp is ok when it is over 25° . Thus suspect one of the temp sensors. Usually they are of the negative family: they decrease when the temp increase. If one goes to open circuit, it means low temp (the computer sees 0v) My car (xantia) has 5 of them: outside air, inside air, air at passenger feet, evaporator freeze, air at mixer out. I made several tests (with a working A/C): disconnect / shunt each sensor to see what happens.. This may help you

-- La vitesse vous effraie ? Windows est fait pour vous.