Undetectable A/C Leak
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Joined: Apr 2010
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From: Fl
Undetectable A/C Leak
Running out of ideas. My 2005 SC430 has so far an undectectable A/C Leak. The A/C system works fine when under a full charge but after 3 weeks or so, the system loses about 1/2 its freon. My mechanic has inserted freon with tracer dye and has yet to find any evidence of a leak. I asked the mechanic if he tried to us a sniffer tool and was told they are not good with 134A freon because the molecules are very small to detect. Never heard of that before but my mechanic has always been true blue on everything else over the many years of service he has provided. With that said, wondering if anyone else has had a simular problem in the past to give me some ideas where to look or have some good suggestions/ideas to offer.
Thank You.
Thank You.
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Joined: Aug 2021
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From: VA
I had a similar issue on my 300,000+ LS460 last year. Went to two shops, with dye in the system, they couldn't find a leak. So they told me it was the condenser in the dashboard. So then I went an pulled the entire dash myself just to find no leaks there either... What I came to think on my system is either, 1. the front A/C condenser had taken a beating and sprung a very small leak that wasn't visible with the dye. Or 2. the o-rings got worn in the connection at the firewall between the systems. If your condenser (in front of the radiator) is very rough/worn, I'd start there. Then I wish you all the luck in fixing the leak without having to pull a dash apart. I got my replacement condenser on rockauto that was rough,but did fit and hasn't leaked in 6-months.
Thread Starter
Rookie
Joined: Apr 2010
Posts: 31
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From: Fl
I had a similar issue on my 300,000+ LS460 last year. Went to two shops, with dye in the system, they couldn't find a leak. So they told me it was the condenser in the dashboard. So then I went an pulled the entire dash myself just to find no leaks there either... What I came to think on my system is either, 1. the front A/C condenser had taken a beating and sprung a very small leak that wasn't visible with the dye. Or 2. the o-rings got worn in the connection at the firewall between the systems. If your condenser (in front of the radiator) is very rough/worn, I'd start there. Then I wish you all the luck in fixing the leak without having to pull a dash apart. I got my replacement condenser on rockauto that was rough,but did fit and hasn't leaked in 6-months.
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Joined: Apr 2010
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From: Fl
Thread Starter
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Joined: Apr 2010
Posts: 31
Likes: 14
From: Fl
Ok, A/C root cause identified and finally resolved. After my local mechanic threw in the towel b/c he could not find the source of the A/C leak, even after using dyes and using a sniffer device. I then resorted to take the car to my local Lexus dealer and let them dive in with the expectations of seeing a big bill. Lexus did not fail as they found the small leak was coming from the evaporator coil. As you can imagine, this repair work required removing the whole front console to gain access to the evaporator to remove and replace it and it was not cheap, as it finally cost me over $3200. So the lesson here folks is, if you happen to have an undetectable A/C leak, chances are it could be either the expansion valve or the evaporator gone bad behind the console. Given my car is a 2005, with 20 years of use here in mostly sunny Florida, I guess it was inevitable for something like this to finally fail.
Last edited by maczones; Jun 1, 2024 at 08:11 PM.
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Joined: Sep 2022
Posts: 73
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From: Nv
Ok, A/C root cause identified and finally resolved. After my local mechanic threw in the towel b/c he could not find the source of the A/C leak, even after using dyes and using a sniffer device. I then resorted to take the car to my local Lexus dealer and let them dive in with the expectations of seeing a big bill. Lexus did not fail as they found the small leak was coming from the evaporator coil. As you can imagine, this repair work required removing the whole front console to gain access to the evaporator to remove and replace it and it was not cheap, as it finally cost me over $3200. So the lesson here folks is, if you happen to have an undetectable A/C leak, chances are it could be either the expansion valve or the evaporator gone bad behind the console. Given my car is a 2005, with 20 years of use here in mostly sunny Florida, I guess it was inevitable for something like this to finally fail.
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