I have had my 05 RL for a year now, and it has fewer than 8k miles on it. After some initial problems, I had started enjoying it until a few weeks ago. I heard a loud noise when driving at low speed in our condo's parking lot (which is quiet compared to the streets). It is NOT associated with braking, and its frequency is associated with the speed of the car. It could be best described as a "Lap, Lap, Lap" sound starting when the car started rolling. It was similar to having a flap of material hitting something that was rotating. Then it went away. I took the car to the dealer, and the service writer was sure it was from the brakes and applied a TSB to the car in which the rotors were resurfaced.



Today, the sound returned, and it is loud. I took the car out again, but the sound went away as soon as I left the parking lot. Thinking that it may be related to the surface of the parking lot, I returned to the lot but the sound did not come back.



Anyone has similar experience?

 

Roll the windows down. Do you hear this sound whenever at low speeds and it appears to "go away" at higher speeds and then return when you decellerate? Is it coming from one side of the car or another? My best guess, one of the TPMS sensors has come loose and is flopping round inside the tire.

 

I have been in a parking lot (with the RL, TL and FX35) and going in the surface made no noise, but going the opposite way create loud noises like you described. I figured because it happened with all three cars that it was the surface. It may not be the same, but the description is the same.

 

Thank you both for the ideas.

It didn't sound like it was something rolling around in a wheel. The sounds were very solid and distinctive. I suspect if the TPMS sensor had been loose, it would have produced more frequent noises when it repeatively rubbed the inside of the wheel than the ones I heard. Also, it would continue as long as the car was rolling.

I have all the windows down, but couldn't pin-point to any one of the corners except that it sounded more like it was from the front. I thought about the direction of driving on the surface of the parking lot, so I drove a few rounds in different directions but failed to reproduce the sound in any direction.

 

gbriank:

I couldn't drive faster than about 20 mph in the lot, and at that speed it was still making the noise. If it was a TPMS sensor, why would the nosie go away at higher speed? Thanks.

 

The centrigual forces at high speed keep the sensor pushed against the tire. At low speeds it flops around. Think about spinning that bucket full of water fast over your head, the water stays in place, go slow over your head and you will get wet.

 

It is a good explaination, but I think it would still grind on the wheel wall and continue to make noise of a different character.

 

I took the car out again, and the noise wasn't there on the way out of the lot and on the road. When I returned to the parking lot, it returned but it was not as loud as before.

There was a lot of gravel by the entrance to the lot, and it has been like that for a long time due to Boston's "Big-dig" construction. I begin to suspect that one of the tires may be catching a particularly large piece of gravel in its threads and making the noise. I could not find a particularly large piece of it, but there were a lot of gravel on the tires, and as I drove more around the lot the noise did go down a little.