A/C it works fine for the first 15 minutes or thereabouts and then starts to blow warm?

2008 MITSUBISHI LANCER
175,000 MILES • 2.0L • 4 CYL • 2WD • AUTOMATIC
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MAUFOS
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Hello, I have the car listed above Fortis (ALA Lancer GTS in the States). When i turn on my A/C it works fine for the first 15 minutes or thereabouts and then starts to blow warm. Things I've noticed, my condenser and radiator fans seem to run at full speed from the time I turn the A/C on. The compressor and condenser fan cycles on and off at first but then runs constantly when the A/C starts getting warm. The car doesn't seem to overheat as my engine temperature gauge stays in the middle, but my ambient temperature reading starts to increase. Also, sometimes with the A/C on, when coming to a stop, I can feel the engine revs drop briefly as if it's about to cut out but then it quickly returns to normal, this does not happen when driving with the A/C off. Things done to vehicle recently, new fans, compressor changed (second hand), seals changed, A/C gassed. Thoughts?
Jan 8, 2024 at 1:09 PM
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STRAILER
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It sounds like the system is overcharged or the compressor is not working correctly but to be sure we need to see the high and low side pressure readings.

These guides and videos will help us see what's going on:

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

and

https://youtu.be/4EqdrBVb0sY?si=NM4brO2WJHUWnfhz

Please go over these guides and get back to us.


Jan 9, 2024 at 9:10 AM
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MAUFOS
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Hello, many thanks for your response, I'm not doing the work myself, but the levels were checked by the tech previously and they were fine according to him, afterwards the car was driven for about 15-20 minutes and the problem surfaced again. When the car is parked for a few hours or overnight and then used, the A/C blows fine again for a few minutes before getting warm again.
Jan 10, 2024 at 5:58 AM
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STRAILER
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When you turn the A/C system on can you hear the radiator cooling fan run?
Jan 10, 2024 at 4:31 PM
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MAUFOS
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Yes, as mentioned initially, the fans run as soon as the A/C is turned on, in fact it sounds as if they are running full speed.
Jan 11, 2024 at 7:35 AM
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STRAILER
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Okay, I had to double check, it sounds like the expansion valve needs to be replaced or the compressor seals are going bad. We need to have the system high and low side pressure readings while the system is not cooling to see what's going on.
Jan 11, 2024 at 10:27 AM
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MAUFOS
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Okay, thanks. I will see if I can have that looked at ASAP.
Jan 11, 2024 at 10:46 AM
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STRAILER
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You are welcome, I think the compressor is no good, but please let me know.
Jan 13, 2024 at 9:40 AM
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MAUFOS
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Hello, my local A/C guy thinks the A/C condenser is the problem, he installed the second hand compressor so I really hope that's not the problem, will let you know when I know more, fingers crossed, thanks.
Jan 17, 2024 at 11:44 AM
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STRAILER
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Sounds good, if I could get the high and low side pressure I can tell you what the problem is as well.
Jan 18, 2024 at 10:30 AM