Aircon losing pressure

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littlepolo
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Aircon losing pressure

Post by littlepolo »

I had the a/c recharged over 18 months ago (it had not been recharged for a long time) and when I attempted to use it this year it had lost pressure. I tried a can of sealant and it started working but has since dropped pressure again. I've had a quick look and cannot see any traces of dye from the sealant, though I can hear some hissing from within the cabin when trying to use a/c. Any ideas on likely failure points?
RUM4MO
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Re: Aircon losing pressure

Post by RUM4MO »

Two common/popular areas for gross leaks are 1) - front mounted condenser due mainly to stone damage or general corrosion, or 2) - evaporator which is inside the cabin within the the "heater" air box.
CarbonChaos
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Re: Aircon losing pressure

Post by CarbonChaos »

Think of your A/C system like a helium ballon,it a sealed ballon filled with gas right ? But after a time it goes down due to the gas seeping through the ballon, if don’t use the A/C then gas will eventually leak out resulting in a low pressure the gas also carries the lubricants around the system keeping your seals and O rings good.
So if you have the system re-gassed it will work for a limited time until the gas has leaked enough to cause low pressure,Extended periods of inactivity will damage these seals to the point where they need replacement.
littlepolo
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Re: Aircon losing pressure

Post by littlepolo »

RUM4MO wrote: Wed Jun 16, 2021 3:57 pm Two common/popular areas for gross leaks are 1) - front mounted condenser due mainly to stone damage or general corrosion, or 2) - evaporator which is inside the cabin within the the "heater" air box.
Thanks. The 'hissing' sound that appears to be coming from behind the dash/firewall area might tie in with the evaporator. Incidentally, I noticed that sound only recently. I think that there are some unions where the a/c hoses/unions pass through the firewall so will remove the engine bay trim and look for any dye/leaks.
littlepolo
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Re: Aircon losing pressure

Post by littlepolo »

CarbonChaos wrote: Wed Jun 16, 2021 8:13 pm Think of your A/C system like a helium ballon,it a sealed ballon filled with gas right ? But after a time it goes down due to the gas seeping through the ballon, if don’t use the A/C then gas will eventually leak out resulting in a low pressure the gas also carries the lubricants around the system keeping your seals and O rings good.
So if you have the system re-gassed it will work for a limited time until the gas has leaked enough to cause low pressure,Extended periods of inactivity will damage these seals to the point where they need replacement.
Thanks. What would you class as an extended period of inactivity?
CarbonChaos
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Re: Aircon losing pressure

Post by CarbonChaos »

Weeks, 6 months tops. Some people think A/C only makes the car cold so only want to use it in the 2 weeks summer we get in the uk.
The fact is if you use it in the winter to heat and dry the air it will aid clearing the windows,if it’s fitted use it or lose it
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