AC system overpressurised?

roverbeast75 · 18th July 2020, 14:37

AC was working as it should not even 12 hours ago. Ice cold. Do note I do not have a working fan so I only use AC above 50 km/h.

My dad took my car without me knowing, he kept using the AC in stuck traffic on a 28°c day. He called me saying the ac was making weird noises, i'll assume this is the ''whooping noise'' it makes when the system is overpressurising.

anddddddd now my AC does not work anymore, yay

The ac compressor turns fine & the clutch engages as it should.

What could be the problem? I filled the gas not even 3 weeks ago and it was working perfectly up until my dad took it..

thanks

Edit: apperantly it was not a wooping noise but a scratching noise , like metal on metal

SD1too · 18th July 2020, 15:59

Quote:

Originally Posted by roverbeast75

What could be the problem?

I'm not sure Jay. The high pressure trinary switch will disable the compressor clutch in extreme conditions but your dad would have noticed if the cooling suddenly stopped.

I think your first move should be to return to your air con. specialist and check the pressures. If necessary he can extract the refrigerant gas to find out if you've lost any.

Simon

roverbeast75 · 18th July 2020, 22:31

Quote:

Originally Posted by SD1too

I'm not sure Jay. The high pressure trinary switch will disable the compressor clutch in extreme conditions but your dad would have noticed if the cooling suddenly stopped.

I think your first move should be to return to your air con. specialist and check the pressures. If necessary he can extract the refrigerant gas to find out if you've lost any.

Simon

Is it possible to lose gas when the system becomes too hot or overpressurised?

Mike Trident · 18th July 2020, 23:18

I recently had a very similar issue with our other car. The fan stopped working, but the aircon was still trying to do its job until it basically overheated and shut down. Even after the new fan was fitted the aircon went through the motions but no cold air. I assumed it had lost all the gas. I went back to have the system filled again but he told me it was full, and I hadn't lost any gas. He decided to regas the system. It then worked perfectly. Left me scratching my head a little. Can the gas be damaged in some way by overheating? I don't know. However, it's still running fine now after the regas.

SCP440 · 19th July 2020, 14:56

I have seen instances where once the system has stopped due to over pressure the only way to fix it is to empty. I presume the trinary switch needs to reset.

roverbeast75 · 20th July 2020, 13:46

Quote:

Originally Posted by Mike Trident

I recently had a very similar issue with our other car. The fan stopped working, but the aircon was still trying to do its job until it basically overheated and shut down. Even after the new fan was fitted the aircon went through the motions but no cold air. I assumed it had lost all the gas. I went back to have the system filled again but he told me it was full, and I hadn't lost any gas. He decided to regas the system. It then worked perfectly. Left me scratching my head a little. Can the gas be damaged in some way by overheating? I don't know. However, it's still running fine now after the regas.

Tried a regass today, did not make a difference... Don't know what to do now, could it be the compressor?

SD1too · 20th July 2020, 15:37

Quote:

Originally Posted by roverbeast75

Don't know what to do now, could it be the compressor?

You need a proper diagnosis Jay. I'm wondering whether you went to a 'Fast Fit' outfit just offering re-gassing.

You've said that the compressor clutch is engaging. Your specialist can tell from his gauge readings whether or not it, and the thermostatic expansion valve, are working correctly.

You definitely need to get your fan operational.

Simon

roverbeast75 · 20th July 2020, 15:50

Quote:

Originally Posted by SD1too

You need a proper diagnosis Jay. I'm wondering whether you went to a 'Fast Fit' outfit just offering re-gassing.

You've said that the compressor clutch is engaging. Your specialist can tell from his gauge readings whether or not it, and the thermostatic expansion valve, are working correctly.

You definitely need to get your fan operational.

Simon

According to his machine , it was working as it should when I was giving gas

SD1too · 20th July 2020, 15:57

When he first connected his machine, was there any gas in your system?

Simon

roverbeast75 · 20th July 2020, 16:04

Quote:

Originally Posted by SD1too

When he first connected his machine, was there any gas in your system?

Simon

Yes , there was, how much exact , I don’t know, when I was walking around the screen I saw 170g but I have no idea how the machine works

18th July 2020, 14:37	#1
roverbeast75 Avid contributor rover 75 Join Date: Jun 2019 Location: ekeren Posts: 106 Thanks: 2 Thanked 19 Times in 13 Posts	AC system overpressurised? AC was working as it should not even 12 hours ago. Ice cold. Do note I do not have a working fan so I only use AC above 50 km/h. My dad took my car without me knowing, he kept using the AC in stuck traffic on a 28°c day. He called me saying the ac was making weird noises, i'll assume this is the ''whooping noise'' it makes when the system is overpressurising. anddddddd now my AC does not work anymore, yay The ac compressor turns fine & the clutch engages as it should. What could be the problem? I filled the gas not even 3 weeks ago and it was working perfectly up until my dad took it.. thanks Edit: apperantly it was not a wooping noise but a scratching noise , like metal on metal Last edited by roverbeast75; 18th July 2020 at 15:37..

18th July 2020, 23:18	#4
Mike Trident Posted a thing or two Rover 75 CDTi Saloon & Citroen C1 Join Date: Jun 2016 Location: Oakenshaw, Near Bradford Posts: 1,622 Thanks: 385 Thanked 552 Times in 328 Posts	I recently had a very similar issue with our other car. The fan stopped working, but the aircon was still trying to do its job until it basically overheated and shut down. Even after the new fan was fitted the aircon went through the motions but no cold air. I assumed it had lost all the gas. I went back to have the system filled again but he told me it was full, and I hadn't lost any gas. He decided to regas the system. It then worked perfectly. Left me scratching my head a little. Can the gas be damaged in some way by overheating? I don't know. However, it's still running fine now after the regas. __________________ Rover 75 2.0 CDTi (131Ps) Conn SE Saloon. (Manual) 160 Remap, cruise control, electric window blind, temp gauge, Real walnut / ZT interior, FBH with GSM control. BORN Tuesday, 5th October 2004 @ 12:35:52 This vehicle was the 104,679th 75 to run off the production line, out of 112,381 This vehicle was the 3,318th 75 CDT Connoisseur SE (135) to be made out of 4,744 This vehicle was the 12,440th 75 in Starlight Silver (code: MBB) to be made out of 14,280 Starlight Silver 75s

20th July 2020, 15:57	#9
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,385 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	When he first connected his machine, was there any gas in your system? Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

19th July 2020, 14:56	#5
SCP440 I really should get out more....... MG ZT-T 260 Join Date: Feb 2016 Location: Witney Posts: 2,504 Thanks: 6 Thanked 910 Times in 571 Posts	I have seen instances where once the system has stopped due to over pressure the only way to fix it is to empty. I presume the trinary switch needs to reset.