Evaporator hissing and compressor slightly noisy

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Evaporator hissing and compressor slightly noisy

Postby Z2TT » Sun Dec 20, 2015 2:07 pm

Hi Guys.

This is a Australian only car so no use mentioning model - TXV Clutch cycling system - 10S17C Compressor with Block Type TXV at Firewall.

This system was giving no issues at all, but recently I have been hearing a hissing noise near the evaporator when the A/C is on. It cools fine as normally to me this is only a cause of a low system charge. What could be causing the issue here, a TXV Issue or perhaps flash gas at the TXV, TXV starting evaporator? Doesn't appear to be as system seems to blow cold air. Hissing only happens when compressor is engaged so it's not like it can be a vent door not closing or something like that so that has been ruled out

Second issue is, compressor appears noisy, it would always make a slight feint rattle for a second just as it engages, but now I'm hearing a rattling noise from the compressor, it's heard in the engine bay but hard to tell as it's masked by surrounding noise, putting a hose to the ear and next to body of the compressor and the rattle is heard.

I doubt the system is low on oil as it has never had any accidents or leaking pipes in the past, car only has about 10,000 miles. I did have a service hose that came loose and lost gas all of a sudden, but at that time I did not risk it and added 50ml of oil to the system just to be safe. This was quite a while ago.

Any suggestions on the noises I am hearing and what could be the possible cause. Do some compressors put our harmonics that simply come normally, I'm unsure if internals can cause this noise or it just may be a prematurely failed clutch bearing. The only noises I have ever heard is buzzing or whining from compressors. This noise is like a feint knocking.

I will measure pressures tommorow and recharge the system.
Any suggestions appreciated.
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