Purring, growling, gargling noise
 

When I accelerate I sometimes hear this high pitched purring or gargling like noise. It is like a series of noises whose frequency increases with RPMs. I suppose one could also describe it as a high pitched growl.

Any idea what that might be? It is odd that I don't hear it all the time. But I heard it yesterday at the same time I noticed my temp gauge rise slightly from its normal position. I suppose it could be related if the noise is coming from the water pump.

whats your radiator fluid level at? maybe its gurgling air?

if it goes away when the car downshifts, then its because the torque converter is locked

Might be a good idea to see if there is air trapped in the system and burp it.

I checked it this morning and I can say that it wasn't full up to the fill neck. I topped off the radiator (didn't need much) and installed a new radiator cap. I didn't burp it but I will check the level again tomorrow and top off again if needed.

The sound is really odd. It is like a series of high pitched pulses where the frequency of the pulses is tied directly to the RPMs of the engine. High pitched purring is the best way to describe it. Like a baseball card in a bicycle wheel but high pitched whirs instead of thwaps. I did notice it some again on my way to work after topping of the radiator but much quieter. I will see if it comes back loud again. It was intermittent the whole time.

I can also say that I saw no evidence of oil in the coolant so that is good news. Maybe I just have a slow leak somewhere and got too much air in the system and maybe the original cap was going bad too. I only saw the temp gauge move that one time and barely above 50%. I really hope it isn't the worst case scenario as I already have a Subaru showing similar symptoms.

Maybe it’s spark knocking. My 2005 rl was spark knocking when I purchased it. I put premium fuel and the noise went away.

You don't mention what year your RL is?

Aside from that, my 2011 was making some funny noises and I was worried about the propeller shaft. Turnout that I had a loose heat shield on the rear side of the motor.

Well, my A/C compressor just seized. That was probably the noise I was hearing. Or it was the air in the system. Happy to report no more overheating events since I replaced the rad cap and topped off the radiator. But a new AC system is gonna be expensive. Ugh.

find a used oem replacement..car-part.com

Not messing with used in this case. Spent $450 for the compressor, condenser, expansion valve and dessicant. Now to see today what the labor cost will be!

A/C is fixed but the sound is still there and it is definitely tied to when the compressor is engaged.

I have a similar issue, and had the AC compressor replaced last year..

I'm thinking it may be related to the PS Pump.. Check your fluid, when I Top it up the noise goes away (even though it toggles on and off with the a/c)

just a theory at this point.

Same issue...