1998 Honda Civic A/C prolem

Hi loochot,

Thank you for the donation.

Evaporator hummiing noise could be due to external pipes or hoses not properly secured, out of alignment or compressor bracket.

Let us know the pressure readings once you have it.

Tubing to and from compressor are secure. The noise I hear is underneath the dash evaporator. It sounds like some sort of restriction. Is there a txv or orfice in that area that woul cause this sound? Is there a superheat or sub cool calculation for 134a systems? I'm trying to narrow down the problem so when I return it to the shop, they don't give me some B.S. answer. Thanks again

Hi loochot,

There is the expansion valve at the firewall joining the evaporator and the external pipes.

I purchased a cheap suction side gage from the auto parts supply. When I checked the pressure, it was maxed out in the red zone. However, once I increased the rpms the pressure would decrease to 60. I removed freon until gage was at 60psig at idle and 35 to 40 psig with rpm increase. Is this normal for the low side reading? This eliminated the the humming noise at the evaporator and lowered the air temp. Ill take it to shop tomorrow and get an accurate reading.

Hi loochot,

The pressure reading is still rather high. The high side reading is needed to confirm what might be the cause.