A/C Question

[Nocturnal]

Hello,

I can't seem to tell if my AC is working properly. It definitely seems like it's trying to blow cold air, but not nearly as cold. I was wondering what I can do to diagnose this issue.

Thanks

 

[enuff_zed]

Take it to a garage that does ac regassing and ask them to do it. Probably just low pressure but they should do a leak check first as well.

 

[Pondy]

As above.
Unless you know what you are doing it is impossible to diagnose problems on the mechanical side of an A/C system.

 

[Nocturnal]

Take it to a garage that does ac regassing and ask them to do it. Probably just low pressure but they should do a leak check first as well.

As above.
Unless you know what you are doing it is impossible to diagnose problems on the mechanical side of an A/C system.

Got it, I’ll look around. Also pardon my knowledge, but could you explain how the system works? My only understanding is that it is a heat exchanger. Wondering where the pressure, refrigerant, etc. comes into play.

Thanks!

 

[Pondy]

It is a basic refrigeration system. So, yes, essentially it 'exchanges' heat by using a compressor, an evaporator coil (cooling coil in the car) and a condenser coil (behind the radiator).
The refrigerant is the 'medium' which absorbs heat at the evaporator and then rejects it at the condenser.
A refrigeration system just moves heat from one place to another, that is it's only function.

It is a sealed system (and under fairly high pressure) so, in theory, it should never need 're-gassing' unless it springs a leak somewhere. However on cars, in practice, they can lose refrigerant without there being a 'leak' as such. This is because the neoprene seal between the compressor and clutch (the bit driven by the belt from the engine) can shrink if not lubricated properly. It is lubricated when the system is running and can dry out if the a/c isn't used for long periods.
When run, the seal will expand as it is being lubricated, so can 'reseal' itself, meaning no leaks but some refrigerant has escaped so the system will need 'topping up' or 're-gassing'.
This seal leaking is the reason why every car manufacturer will say the a/c system should be used on a regular basis.

The a/c system in a car uses very little refrigerant (around 200 grams). It is 'critically charged', ie needs an exact amount of refrigerant for it to operate properly. If the system loses even a small amount of refrigerant, it won't work properly. They also have safety switches, so if the refrigerant charge drops by too much, it will stop the compressor from kicking in to protect the system from damage.

Of course, there are also a myriad of other things that can fail on the system, like any other electro-mechanical system.

HTH.

 

[Mr Tidy]

One thing you can do is have the engine running with the bonnet open then turn the A/C on. You should hear the compressor engage and the electric fan start operating.

My E46 just needed a regas, but my 2nd Z4 wouldn't hold pressure because it needed a new condenser.

My current Z4 got a regas in 2021, but a year later it turned out it needed a new electric fan because the refrigerant was getting too hot and getting over pressure so being lost from the pressure relief valve - well that's what I was told anyway!

E90 had a regas last June - I'm hoping it will still be fine if we get a summer this year.

 

[buzyg]

It is a basic refrigeration system. So, yes, essentially it 'exchanges' heat by using a compressor, an evaporator coil (cooling coil in the car) and a condenser coil (behind the radiator).
The refrigerant is the 'medium' which absorbs heat at the evaporator and then rejects it at the condenser.
A refrigeration system just moves heat from one place to another, that is it's only function.

It is a sealed system (and under fairly high pressure) so, in theory, it should never need 're-gassing' unless it springs a leak somewhere. However on cars, in practice, they can lose refrigerant without there being a 'leak' as such. This is because the neoprene seal between the compressor and clutch (the bit driven by the belt from the engine) can shrink if not lubricated properly. It is lubricated when the system is running and can dry out if the a/c isn't used for long periods.
When run, the seal will expand as it is being lubricated, so can 'reseal' itself, meaning no leaks but some refrigerant has escaped so the system will need 'topping up' or 're-gassing'.
This seal leaking is the reason why every car manufacturer will say the a/c system should be used on a regular basis.

The a/c system in a car uses very little refrigerant (around 200 grams). It is 'critically charged', ie needs an exact amount of refrigerant for it to operate properly. If the system loses even a small amount of refrigerant, it won't work properly. They also have safety switches, so if the refrigerant charge drops by too much, it will stop the compressor from kicking in to protect the system from damage.

Of course, there are also a myriad of other things that can fail on the system, like any other electro-mechanical system.

HTH.

Enjoyed reading that Pondy.

 

[x-driver]

Take it to a garage that does ac regassing and ask them to do it. Probably just low pressure but they should do a leak check first as well.

As above.
Unless you know what you are doing it is impossible to diagnose problems on the mechanical side of an A/C system.

Got it, I’ll look around. Also pardon my knowledge, but could you explain how the system works? My only understanding is that it is a heat exchanger. Wondering where the pressure, refrigerant, etc. comes into play.

Thanks!