Aircon Pressure Low 4psi…

[Deepseaskateboard]

After the fourth time of being nagged the aircon was not cold, I ran over to Halfords for their free air con diagnostic.

He plugged in a reader to the aircon nozzle to gauge system pressure and it returned 4psi, he said it should be around 150!

I have owned the car for nearly five years, never had it topped up with refrigerant…

Is this fairly common for Z4s? It’s a 2012 20i if that makes any difference.

He gave it a quick visual check under the bonnet and said he couldn't see anything obviously wrong with the hardware.

He said it was normal for cars to lose about 10% per year….

So question time:

A: would you say this is fairly normal?
B: what is the correct PSI of the system, or where can I find this out? My Dad was saying some places just max out the pressure rather than using the correct amount!

Thanks all!

[craigdm]

Screenshot_20210605-115031.jpg (100.91 KiB) Viewed 1058 times

150psi sounds very high. Here's the chart that I use when filling my old MX5 with the kits you buy on line

[SV8Predator]

He gave it a quick visual check under the bonnet and said he couldn't see anything obviously wrong with the hardware.

He's got X-Ray eyes then?

Take the car to an air-con specialist, or an indy or main dealer that has air-con trained personnel.

If the gas is low, it's because it has leaked out. You cannot see this with a "visual check"!

UV dye will be added, the system pressurised and then (correctly) inspected with a strong UV light to find the leak.

[Mr Tidy]

Not an E89, but my 2nd Z4 had non-working A/C a few years ago which that turned out to be a damaged condensor.

So when my current one was blowing slightly chilled air in June I was expecting something similar. But when I took it to my Indy the system held pressure under test so just needed a regas and all was good.

He didn't mention pressure, but said I only had 130g of refrigerant - it should have been 700g IIRC. So it only cost me £65 this time.

A few years ago the A/c in my E46 wasn't working too well and that turned out to just need a regas, so it doesn't seem unusual for some of the gas to escape over time.

[Silverstar]

A few years ago the A/c in my E46 wasn't working too well and that turned out to just need a regas, so it doesn't seem unusual for some of the gas to escape over time.

Especially if you don't use your air con all year round. You have to use it regularly to keep the A/C system in good shape or else it can cause problems.

[Argyll Andy]

Don’t know if there’s one near you or not but ATS via Groupon giving decent discount

http://www.groupon.co.uk/deals/ats-euro ... =undefined

[Deepseaskateboard]

Thanks for the feedback chaps.

Ill have a look at ATS, don’t often use the aircon in a roadster!

Perhaps thats why it’s gone!

I am presuming he hasnt Xray vision, or would have run the risk of being emasculated but he checked over the radiators at the front… I have no idea where the condenser is.

I do hope it’s just a case of a recharge with no hardware failure. I bet it’s an expensive fix!

[mcbutler]

A few years ago the A/c in my E46 wasn't working too well and that turned out to just need a regas, so it doesn't seem unusual for some of the gas to escape over time.

Especially if you don't use your air con all year round. You have to use it regularly to keep the A/C system in good shape or else it can cause problems.

Well saidAC should be used frequently, at least run for an one hour (ish) a month. The system has a lubricant as well as the refridgerant gas inside. When you turn it on its all circulating and seals etc are lubricated. If you dont use it seals can dry out and leak

[Silverstar]

I am presuming he hasnt Xray vision, or would have run the risk of being emasculated but he checked over the radiators at the front… I have no idea where the condenser is.

The condenser is at the front behind the bumper, it looks like a radiator.

Well saidAC should be used frequently, at least run for an one hour (ish) a month. The system has a lubricant as well as the refridgerant gas inside. When you turn it on its all circulating and seals etc are lubricated. If you dont use it seals can dry out and leak

100% correct. What many don't realise is that you can use the air con for heating and cooling too. It really is a case of use it or loose it.

[Deepseaskateboard]

I am presuming he hasnt Xray vision, or would have run the risk of being emasculated but he checked over the radiators at the front… I have no idea where the condenser is.

The condenser is at the front behind the bumper, it looks like a radiator.

Well saidAC should be used frequently, at least run for an one hour (ish) a month. The system has a lubricant as well as the refridgerant gas inside. When you turn it on its all circulating and seals etc are lubricated. If you dont use it seals can dry out and leak

100% correct. What many don't realise is that you can use the air con for heating and cooling too. It really is a case of use it or loose it.

So if they dry out, is it a case of replacement, or do they absorb any oil added to the system, or liquid etc?

[mcbutler]

I am presuming he hasnt Xray vision, or would have run the risk of being emasculated but he checked over the radiators at the front… I have no idea where the condenser is.

The condenser is at the front behind the bumper, it looks like a radiator.

Well saidAC should be used frequently, at least run for an one hour (ish) a month. The system has a lubricant as well as the refridgerant gas inside. When you turn it on its all circulating and seals etc are lubricated. If you dont use it seals can dry out and leak

100% correct. What many don't realise is that you can use the air con for heating and cooling too. It really is a case of use it or loose it.

So if they dry out, is it a case of replacement, or do they absorb any oil added to the system, or liquid etc?

Replacement

[Pondrew]

After the fourth time of being nagged the aircon was not cold, I ran over to Halfords for their free air con diagnostic.

He plugged in a reader to the aircon nozzle to gauge system pressure and it returned 4psi, he said it should be around 150!

I have owned the car for nearly five years, never had it topped up with refrigerant…

Is this fairly common for Z4s? It’s a 2012 20i if that makes any difference.

He gave it a quick visual check under the bonnet and said he couldn't see anything obviously wrong with the hardware.

He said it was normal for cars to lose about 10% per year….

So question time:

A: would you say this is fairly normal?
B: what is the correct PSI of the system, or where can I find this out? My Dad was saying some places just max out the pressure rather than using the correct amount!

Thanks all!

There is a lot of mis-information and common myths about this subject. This is how it works (I am a refrigeration engineer BTW and worked on car a/c for many years).

The A/C system is sealed. It should never leak unless there is a problem.
How many times do you have your 'fridge at home "re-gassed"? Never.
However, having said the above, it is common for the neoprene seal on the drive pulley/shaft of the A/C compressor to weep refrigerant if it is not used for long periods. The seal is lubricated when the compressor is running, so can dry out and shrink slightly if not used regularly. Once run again, the seal will lubricate, expand and then can seal again. This why all car owners manuals say about using the a/c every few weeks, to keep this seal from shrinking.

A garage should NEVER just do a "regas". They should pressure test the system with dry Nitrogen, as the leak could be coming from anywhere (condenser/ a/c radiator is the most common place). Then the system should be evacuated before charging. It is actually against the law to wilfully or knowingly discharge refrigerant into the atmosphere, so just re-charging without any other checks is potentially doing this.

The standing pressure of a healthy R134a refrigerant car system, which all E85, 86 and 89s are, will be approximately 60-80 PSIg, depending on ambient factors and heat within the engine bay. It is immaterial to the owner, though, as it is also illegal to attach pressure gauges to the system unless you have the relevant qualifications.

The A/C system on a car is also 'critically charged', which means it should be weighed into the system to the correct amount. The charge weight should always be written on the a/c label usually under the bonnet. Overcharging, or undercharging, will cause problems and eventually damage to the a/c system.

HTH

[ori]

I used to work in aircon.

Firstly it is not normal for an ac system to lose 10% a year. That only happens if there is a leak. It’s a sealed system and in theory should never need to filled.
The problem people have is that they turn off the a/c for 9 months and then fire it up in the summer. This is the worst thing to do. Without the oil circulating, the seals dry up and that’s how leaks end up happening.

My advice to all car owners is to leave the a/c on all year round It will help with condensation too.

[Deepseaskateboard]

After the fourth time of being nagged the aircon was not cold, I ran over to Halfords for their free air con diagnostic.

He plugged in a reader to the aircon nozzle to gauge system pressure and it returned 4psi, he said it should be around 150!

I have owned the car for nearly five years, never had it topped up with refrigerant…

Is this fairly common for Z4s? It’s a 2012 20i if that makes any difference.

He gave it a quick visual check under the bonnet and said he couldn't see anything obviously wrong with the hardware.

He said it was normal for cars to lose about 10% per year….

So question time:

A: would you say this is fairly normal?
B: what is the correct PSI of the system, or where can I find this out? My Dad was saying some places just max out the pressure rather than using the correct amount!

Thanks all!

There is a lot of mis-information and common myths about this subject. This is how it works (I am a refrigeration engineer BTW and worked on car a/c for many years).

The A/C system is sealed. It should never leak unless there is a problem.
How many times do you have your 'fridge at home "re-gassed"? Never.
However, having said the above, it is common for the neoprene seal on the drive pulley/shaft of the A/C compressor to weep refrigerant if it is not used for long periods. The seal is lubricated when the compressor is running, so can dry out and shrink slightly if not used regularly. Once run again, the seal will lubricate, expand and then can seal again. This why all car owners manuals say about using the a/c every few weeks, to keep this seal from shrinking.

A garage should NEVER just do a "regas". They should pressure test the system with dry Nitrogen, as the leak could be coming from anywhere (condenser/ a/c radiator is the most common place). Then the system should be evacuated before charging. It is actually against the law to wilfully or knowingly discharge refrigerant into the atmosphere, so just re-charging without any other checks is potentially doing this.

The standing pressure of a healthy R134a refrigerant car system, which all E85, 86 and 89s are, will be approximately 60-80 PSIg, depending on ambient factors and heat within the engine bay. It is immaterial to the owner, though, as it is also illegal to attach pressure gauges to the system unless you have the relevant qualifications.

The A/C system on a car is also 'critically charged', which means it should be weighed into the system to the correct amount. The charge weight should always be written on the a/c label usually under the bonnet. Overcharging, or undercharging, will cause problems and eventually damage to the a/c system.

HTH

Very helpful, thank you.