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The mkiv Supra Owners Club

Air con hissing noise?


Benzsupra

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Hi everyone,

I have done a quick search and found some similar questions asked but there were no clear answers so...

 

I have recently had my air con system re-gassed and it was working fine however after fitting my new dials and re-assembling the dash the air con does not seem to be getting very cool and there is a relatively loud hissing noise in the passenger footwell area. Any ideas? I'm assuming the noise and the lack of cold air are related but i have no idea what it could be. Also when i push the air con button the compressor engages and the revs go higher as normal but they don't drop at all, the compressor engages but doesn't disengage which would be the normal thing. I'm hoping i have just knocked something but if anyone has any ideas please help. I won't turn it on again until i have solved it because i don't want to break anything else.

 

Thanks

Ben.

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I've got no idea, But it sounds like maybe the pipe has dropped off, So the air is escaping lower down, Creating the hiss. Is the pressure coming out the vents lower than normal ? Also I belive there is a sensor that is behind the dash, I think (Not concrete on this) this has something to do with the aircon, Make sure thats not been shifted.

 

Other than that maybe a snake ???:search:

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This is due to a lack of gas in the system. Soon it'll probably stop completely as the safety cut-out engages. If you've just had it regassed and it's gone already it means:

 

1) They didn't put enough in

2) It's leaking

 

As you say it *was* ok for a bit after regas, I think it's option 2. It's going to need a specialist to track down, and in the years that mien has been playing up I've had it regassed 5 times, replaced the air con condensor and the air con pump.

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Right after a little bit more investigation it appears that the hissing is coming from behind this cover i've circled on the diagram (obviously the other way around this is from an American car) I've had a look in the little preview window on the gas top up pipe and there seems to be fluid of some sort whirling around in there but no bubbles or anything. The compressor engages but does not disengage periodocially as it usually would and iirc the hissing noise always happens when you turn the air con on but goes away when the compressor clutch disengages. The air in the car does not get any cooler weather it is on or off.

 

When i bought this car it had just had the air con re-done and he had the receipt to prove this. I seem to remember that when i went to have it done myself on previous cars the machine checked for leaks before re-gassing is this right? I have no problem getting it done again but i don't want to waste my time and money. It was absolutely perfect before i disconnected the battery now this is what i get, is there some way that having the battery off has caused the system to discharge or something? I really don't know too much about it but i know what it's supposed to do. The fact that the compressor never kicks in and out seems very strange to me.

 

Any ideas after that bit of input?

 

supra.jpg

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