Hi all,

I tried searching the forum with no luck. Upon start-up of my 2010 Lexus RX350, there's an annoying squealing sound coming from the front hood. It usually squeals while idling, then picks up in intensity when accelerating. After about 10-15 min of driving, it usually goes away. Dealer couldn't replicate the issue, they said. It almost sounds like a belt, but it's difficult to isolate where exactly it's coming from. My wife just crossed over 100K miles a few months ago. Anyone have any idea what might be causing this?

 

Does it happen when the AC is off?

 

If it sounds like a belt and squeals like a belt; it's probably the belt.
Replace it and go from there. Perhaps an idler or tensioner (belt related) are to blame. This should be checked during belt replacement.

 

Next time you hear it, immediately turn off the AC and most likely it will go away. If that is the case, it is the Alternator belt that is loose. When did u last change the belt? It can be tightened or if old, just replace it.

 

Thanks! I figured it was a belt. I'm not a mechanic by any means, but I assumed there are multiple belts it could be. Was just curious if anyone else had a similar problem and could share their experience since my dealership couldn't seem to replicate the problem.

 

Okay, interesting. I believe it squeals whether or not the air conditioner (or heater) is on when the car starts and doesn't seem to get better or worse if we turn on the A/C after starting up. For what it's worse, the squeal was even louder in the winter. In general, the car is kept in the garage most nights, but we have noticed that the squeal is worse on a cold start the night after it sits outside in the rain.

 

I agree with the above posts.

 

I would start by tightening the AC/Serpentine belt. If they cannot replicate the issue, just ask them to check the tension in the belt and tighten it.

 

Thanks all!

 

There is no separate AC belt, just the single serpentine that drives all accessories. This belt cannot be tighten manually like older cars. The RX uses an spring-loaded tensioner that automatically applies force onto the belt.

FindMe, I would start by replacing the serpentine belt. While the belt is off, turn all the pulleys to make sure there is no wobble or hard-spots.

 

When the serpentine belt was changed on my Highlander (same engine as yours) at 90K, I got squealing upon start when the A/C was on. Changing the belt solved the problem. I think changing the belt on your RX if it has 90K would be a good investment.
Ray A.

 

If my car was occasionally squealing at startup and it was 6_ year old and had 100,000 miles, I would have the Serpentine belt changed regardless. . With the belt removed the mechanic can check to see if either the water pump, power steering pump or alternator has excessive drag or a perhaps bad bearing.

Cost to replace a serpentine belt should run about $100-150 from an independent shop. http://www.autorepaircompare.com/

I would call your local Lexus and Toyota dealers for quotes first, as they use OEM parts and are experienced with the engine.