2005 Mitsubishi Galant A/C Noise

Hi rpespinel,

Thank you for the donation.

To a certain extent, such noise do exist in AC systems and some cannot be resolved. It usually is caused by the expansion valve. Was it replaced during the replacement of the evaporator and if yes, was it OEM standard?

Replacing the expansion valve might have made a diffference but there are other possible concerns.

Possible causes for the noise.

Whistling type of noise would be due to the evaporator, some evaporators produce such noises even though it could be OEM. This cannot be resolved as is it a design fault and you would have to get another one, maybe from a different supplier.

If the noise is gurgling or slightly hissing type :

1. Faulty expansion valve. If the system was discharged too fast or incorrectly it would cause the expansion to fail. However this could also be due to the valve failing when the system leaked. Replacement wuold resolve the problem.

For items 2 and 3, they can be done without any removal of components and you could give it a try.

2. Insufficient gas in system. When insufficient gas is n system, the gurgling would be noticeable when the compressor cycles on and off. Recheck the gas pressure.

3. Improper vacumn before refilling of gas. When insufficient or improper vacumning of syatem was carried out, air could be trapped in system and this would cause the noise. Get the shop to recover the gas and revacumn the system before refilling the gas and see if it helps.