It seems as if the front belt on my car has gotten louder and louder recently. It was super quiet before but now it loud enough I can hear the car running on the other side of a 40 car garage. I work at a dealership (not Lexus but a reputable make) and when I told the service manager he sprayed something on the belt that made the noise go away. The next day it was back and I told him, he said that since it came back that means the belt must be changed. So my questions is, is it really the belt must be changed or one of the pulleys?

 

You are most likely talking about the serpentine (drive) belt. That spray method is just a way of detecting the source of the problem, which of course is the belt. It is not meant to be a permanent fix. You should order a new belt and have it replaced.

 

.
How many miles on your GS? I think I had around 60k on my GS300 when I had to change out the serpentine belt. It was making tons of noise.

 

I was at the dealer the other and they indicated that my belt would need changing soon - for $90. Is that a reasonable price?

 

I just had my 90k service done recently, where they replaced the serpentine belt. Im already hearing a slight grumbling noise from under the hood, but only when the a/c is on. When I turn it off, the noise goes away. needless to say I have to take the car back in this weekend to have it checked. It may or may not be similar to what you're experiencing.....

 

I had my 90k service done, i dont think they changed that belt although that was last year and since then ive only put 1,300 miles on the car so maybe it rotted.