Bud

I have a 99 RX AWD with just over 100k on it...I had the timing belt and water pump replaced a few months ago...when the engine is idiling I get a wierd noise coming form the engine...now the car idles at the correct RPM and the engine runs fine as far as i know...the MPG are good and when the car is idiling and give it some gas the noise (as far as I can hear) does not get any worse and might even go away...I have tried to pinpoint exaclty where the noise is coming from and the best to my ability it sounds like it is coming from the belt side of the motor...but i can't pin point it...it sounds as if 'something' needs to be tightened or there is a 'hole' somewhere...

Anyone else have this type of issue? I know Lexus has said that RX after time sounds like a diesel, but the noise has gotten worse...the only other info I have and I am not sure if it's connected but when I am running the air con and turn the engine off and start the engine 10-15 mins later I sometimes get a very loud screeching noise from the belts until i turn the A/c off then it goes away immedialty and i can then turn the air back on.

Any help would be great.

TunedRX300

The sharp screeching is from your loose power steering belt, you should replace or at least tighten it.

Lil4X

Your compressor is stalling against high head pressure. When you start a cold engine in the morning the compressor sees little resistance - the pressure differential between the high and low sides having leaked down overnight. But after a few seconds of operation, your compressor can develop up to around 400 psi of differential between the high and low sides. When you re-start under these conditions, it requires TORQUE to get the compressor moving against all of that pressure, and a loose belt will scream in protest.

Have your accessory belt checked by your dealer or a good AC shop. Replace or just tighten as needed. They should be careful not to over-tighten because they can but the bearings in your accessories - compressor, power steering pump, etc. in a bind and cause additional problems.

Bud

Thanks for the info...I called my local Lexus dealer and brought the car in since the timing belt and serp belt were just put on..they did a tension test on the belts and said that the belts were just fine...but they notice two other issues

1. The AC clutch needs to be replaced because most likley the bearings are shot and that would be $800.00...they did say that while it is making some noise it's not necessry to fix because it's not affecting the performance of the engine...however if the berings were to freeze up it would be a serious problem

2. The exhaust manifold has a leak and the cost to replace is $700.00...while this is purely a noise issue it's not overwhelig but is the casue of the car sounding like a diesel.

Looking for a little feedback on whether or not I should get either of the two fixed and whether or not the prices seem reasonable...I am more concerned about the first one than the second one.

Thanks

Lil4X

IF the problems is in your clutch only, that's not a difficult replacement. I'm not sure what bearings there are in your A/C clutch, but I'll defer to superior knowledge on this one. Compressor repair is a bit more complex, considering they would have to pump off your refrigerant, R/R a new compressor, recharge and leak test your system (probably will want to replace dryer element while doing this).

The manifold could probably be fixed for a bit less by removing it and welding up the crack rather than replacement. This requires an experienced and qualified welder, not just your garden-variety "burner".