Hi folks. When I start my car, it was making a horrible grinding noise. People walking by were startled when it happened. At first, I thought it was the starter and read they rarely fail. I found this thread on the SC430 forum and decided to take a look.

https://www.clublexus.com/forums/sc4...-starting.html

Sure enough, the power steering fluid reservoir had a leak and was completely dry. The alternator wiring bracket bolt was also broken. After repairing both of them, the grinding noise continued for about a week. I suspect the remaining PS fluid wore off the alternator and the noise eventually went away. Do you think the PS fluid affected the alternator? Should I replace the alternator?

 

I think you should get the alternator tested, and if it passes, leave it alone.

I know when it dropped into single digits last winter, my wife's SUV was making a grinding noise. The PS rack was replaced when the vehicle was < 2 y.o. as it was a known GM defect. Never so much as touched it in our ownership. The engine ornament has to be removed to expose the reservoir. Sure enough, topping off the fluid, the sound went away.

Seems to me you are saying PS was in fact repaired on your vehicle but the grinding did not go away. I know on my Nissan I dealt with a starter that intermittently made a grinding sound for about 4 years. One day it simply failed and left me stranded, the only time that car ever did, in 21 1/2 yrs on the road. With the bad replacement parts I'm actually now an expert on replacing the starter on that car. I would shy away on the LS after I saw the procedure, though.

 

Your alternator is fine it gets liquids nd other debris on it with normal driving so I wouldnt worry to much, but if testing it will give you piece of mind go for it.

 

Thanks for everyone's feedback. Autozone said the alternator was fine. I continued to hear a grinding noise when starting the car (albeit not as loud). I went ahead and replaced the alternator and the noise is gone.