Hello! base highlander model with 135K, runs great. About 8 months ago I noticed an intermittent 'growling' sound coming from the pulley areas of the engine. It was very hard to notice it at the time, it was sporadic only occurring about 2x/week. I knew it could be a problem so I had my local mechanic take a look and he couldn't identify the sound, he even drove it around to let it warm up and still couldn't diagnose what I was hearing. He checked all the pulleys at the time and said they were all good, but the best he could do was change the belt, so I agreed to that. Unfortunately, that didn't stop the sound. Currently, over the past 2 weeks, the sound is worsening and definitely only occurs when the A/C is on. Since it's colder here in Florida I'm not running the A/C so much, but when I turn it on... the sound starts immediately, like a slow growling type of chugging sound. The A/C works fine, don't notice any change with the functionality of the A/C unit. But my question is what to do? Does this mean the compressor is failing, or is there a separate pulley to replace on the compressor? Is it just a sound and I need to live with it? I'd rather not replace it but also not sure if run to fail is a good idea. THANK YOU!
It could be the compressor, or any other pulley in the path since the compressor puts a big load on the belt. A mechanic's stethescope should help pinpoint the noise. You could also turn the AC compressor by hand to check for any roughness, binding, or noises. (You need to turn the clutch plate, not the pulley.) If the compressor is making the noise you'll want to replace it before it seizes up and contaminates your AC system, which would require every component to be replaced. Only use a new replacement compressor if needed, not rebuilt.
Thank you, very concise answer, I appreciate it!