AC System Whale Sounds

aflynn · 16th May 2024, 17:15

Hello there folks,

When I first purchased my ZT three years ago, I had nice cold AC, however a few years on and it has slowly gotten warmer over the years. I checked the pressure on the system and it was around the 20psi mark on the gauge (this was using a top up hose plugged into the low port) seeing as the system had some refrigerant already within the system and pag and dye, I decided to top the system up using a small DIY can (yes I know it's not the advisable route). I topped up the system yesterday, most of the gas went in and the gauge rose to around the 33-35 psi on the dial. I Checked the vents, and it was now blowing nice and cold again. However, I decided to test the system this morning, I could hear whale sounds emanating from the bulkhead. I immediately shut the system down. I retested when I got back to my car after work, when the system was at ambient temp, it ran fine for 5 minutes though as a drove down the road, I could hear the compressor switch off and kick back in again and the whale sounds began again. From my understanding, this noise is due to the gas within the system becoming too hot, the "whale" sounds is due to the pressure from the gas releasing? Now, the fans do kick in straight away upon switching on the AC so this must be cooling the gas or attempting to, I checked lines within the engine bay afterwards, they appeared to be a reasonable temp, cold on one hot on the other, though not hot enough to burn, I then re-connected the pressure gauge, it was in the red without the system running, upon switching the AC on and the condenser kicking in, this slowly dropped to around 34psi. The pipes do get rather hot if the AC is switched off from radiated heat within the engine bay. I am not entirely sure if my fan works on the 3 speed settings, I was sat in traffic and I heard the fan kick in, it didn't appear to be as fast or loud as it is whilst switching the AC on. All this said and it appears I have a leak in the system anyway, I can see green fluorescent fluid dripping on the left side of the drivers footwell, this appears to be coming from the aluminium block on the evaporator so this may be a costly job to repair.

suzublu · 16th May 2024, 17:39

When I was going through the same thing

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SD1too · 16th May 2024, 22:49

Quote:

Originally Posted by aflynn

I am not entirely sure if my fan works on the 3 speed settings, I was sat in traffic and I heard the fan kick in ...

To clarify Adam, when you select 'Auto' or preferably the windscreen demist setting, your radiator fan should run at slow speed continuously whether your car is stationary or moving.

Quote:

Originally Posted by aflynn

... I decided to top the system up using a small DIY can (yes I know it's not the advisable route).

You're absolutely right, it isn't the correct way to do it at all. Refrigerant charge is not determined by pressure but by weight.

Quote:

Originally Posted by aflynn

... it appears I have a leak in the system anyway, I can see green fluorescent fluid dripping on the left side of the drivers footwell, this appears to be coming from the aluminium block on the evaporator ...

That's unheard of and may be the result of your DIY can overcharging the system leading to excessive pressure. You should seek a mobile self employed specialist (or a company with premises if you can find one) to help you.

Simon

aflynn · 17th May 2024, 17:15

An update on the issue, and a warning for anyone reading this thread in future in regards to re-gassing your AC system with cans. DO NOT DO IT. take your car to an approved technician. Sometimes you learn the hard way and it was very silly of me to use this method. It turns out that the AC system was over filled. The low gauges on the system do not give adequate readings and quite frankly this method of filling should not be carried out under any circumstances. After allowing the gas to settle and the pressure to equalise I plugged in the dial to find the pressure shot off the chart in the red, this was highly dangerous and it obviously the cause of the issue. I was very lucky in this circumstance that no seals were blown, and to be honest I don't know how the system held up. As for the leak I mentioned, this has been there for some years and I have been aware of it, it's the TX valve pipes where the condenser is which will require replacement at some point.

16th May 2024, 17:15	#1
aflynn Regular poster MG ZT Join Date: May 2021 Location: Manchester Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts	AC System Whale Sounds Hello there folks, When I first purchased my ZT three years ago, I had nice cold AC, however a few years on and it has slowly gotten warmer over the years. I checked the pressure on the system and it was around the 20psi mark on the gauge (this was using a top up hose plugged into the low port) seeing as the system had some refrigerant already within the system and pag and dye, I decided to top the system up using a small DIY can (yes I know it's not the advisable route). I topped up the system yesterday, most of the gas went in and the gauge rose to around the 33-35 psi on the dial. I Checked the vents, and it was now blowing nice and cold again. However, I decided to test the system this morning, I could hear whale sounds emanating from the bulkhead. I immediately shut the system down. I retested when I got back to my car after work, when the system was at ambient temp, it ran fine for 5 minutes though as a drove down the road, I could hear the compressor switch off and kick back in again and the whale sounds began again. From my understanding, this noise is due to the gas within the system becoming too hot, the "whale" sounds is due to the pressure from the gas releasing? Now, the fans do kick in straight away upon switching on the AC so this must be cooling the gas or attempting to, I checked lines within the engine bay afterwards, they appeared to be a reasonable temp, cold on one hot on the other, though not hot enough to burn, I then re-connected the pressure gauge, it was in the red without the system running, upon switching the AC on and the condenser kicking in, this slowly dropped to around 34psi. The pipes do get rather hot if the AC is switched off from radiated heat within the engine bay. I am not entirely sure if my fan works on the 3 speed settings, I was sat in traffic and I heard the fan kick in, it didn't appear to be as fast or loud as it is whilst switching the AC on. All this said and it appears I have a leak in the system anyway, I can see green fluorescent fluid dripping on the left side of the drivers footwell, this appears to be coming from the aluminium block on the evaporator so this may be a costly job to repair. Last edited by aflynn; 16th May 2024 at 17:56..

16th May 2024, 17:39	#2
suzublu This is my second home rover 75 1.8 vvc club se wedgwood blue Join Date: Aug 2009 Location: Seaton Carew Posts: 26,956 Thanks: 65 Thanked 7,142 Times in 4,642 Posts	When I was going through the same thing Sent from my SM-A145R using Tapatalk

17th May 2024, 17:15	#4
aflynn Regular poster MG ZT Join Date: May 2021 Location: Manchester Posts: 32 Thanks: 0 Thanked 0 Times in 0 Posts	An update on the issue, and a warning for anyone reading this thread in future in regards to re-gassing your AC system with cans. DO NOT DO IT. take your car to an approved technician. Sometimes you learn the hard way and it was very silly of me to use this method. It turns out that the AC system was over filled. The low gauges on the system do not give adequate readings and quite frankly this method of filling should not be carried out under any circumstances. After allowing the gas to settle and the pressure to equalise I plugged in the dial to find the pressure shot off the chart in the red, this was highly dangerous and it obviously the cause of the issue. I was very lucky in this circumstance that no seals were blown, and to be honest I don't know how the system held up. As for the leak I mentioned, this has been there for some years and I have been aware of it, it's the TX valve pipes where the condenser is which will require replacement at some point.