I have a 1999 Plymouth Grand Voayger with front and rear air conditioning. Lately, I’m hearing a hissing noise when the AC is on. Sometimes it comes from the front unit and sometimes from the rear unit and is intermittent in nature. The air conditioner still seems to be cooling o.k. Also, I do not get this problem when just using the heat settings, only AC. Any ideas would be greatly apprciated.
Thanks.
If you can find the window on the receiver/dryer, watch it as the compressor cycles (engine runnning and A/C on). If the window starts clear, shows froth, and then shows flowing liquid, the system is working as it should. If the froth never clears, the system is a little low on freon.
Hope this helps.
Most likely you want to be as certain as possible that a large repair is not waiting around the corner,I sense this is your motivation for writing to us.
Your description of the concern is all over the map, I can’t do much with it, what I can suggest,
Get a set of experienced eyes on your cars AC system. Check pressures,temperatures,mode door function, in short check all that is practical without expensive disassembly.
Stay away from the loss leader pricing to get you in and checked out. I sense you are willing to pay a reasonable diagnostic/check out fee.
Don’t forget to mention that a hissing noise prompted you to seek a professional. I am trying to steer you away from a situation where you pay but don’t come away feeling more confident.