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Weird noise... from evaporator?
Posted: Mon Jul 06, 2020 9:03 pm
by GhostLake
Hello all, I'm no A/C expert but have been working on cars otherwise for many years. The A/C on my 2000 Dodge Dakota makes an unusual noise when it's turned on that comes from the passenger compartment (see link below). There are no abnormal sounds from the compressor. It has a slow leak which I discovered is coming from the low side port. When hooking up manifold gauges, the high side registers low though off the top of my head I don't remember the number. Could that be causing this strange noise, something else? I've never heard an A/C make this noise. And it only makes this noise when the A/C is on. Thanks
https://youtu.be/v-sRAmpggM0
Re: Weird noise... from evaporator?
Posted: Mon Jul 06, 2020 11:28 pm
by Dougflas
Have you recovered the refrigerant and recharged by weight? Sounds as if the compressor is cycling but you said the compressor is not making the noise. Another source can be refrigerant moving thru the metering device because of low charge.
Re: Weird noise... from evaporator?
Posted: Tue Jul 07, 2020 7:22 am
by Tim
Al9 wrote:The growling sounds like a discharge reed valve noise known as the Sanden rumble. If this is the cause, if the rumble won't quieten or go away by restoring the proper charge then it's fixed either by fitting a muffler or a new reed valve plate (or a new compressor equipped with a new reed valve plate).
The hissing sounds like vapor entering/moving through the evaporator (while this is supposed to be a flooded evaporator system since it has a orifice tube, so liquid should be moving through it).
Cycling sounds really short.
Don't run it until the leak is fixed and the proper refrigerant charge weight is restored, or
this could possibly happen. Not pretty.
This sounds correct. I would bet it is down on refrigerant and oil at this point. Sandan rumble will always be present. The newer compressors are better in this area.
Re: Weird noise... from evaporator?
Posted: Wed Jul 08, 2020 7:53 pm
by GhostLake
I'm going to have the refrigerant collected then replace some seals, low side port and drier. I'll then add refrigerant by weight and see what happens. I appreciate the responses and information. Thanks!