All,
I have a chirp. At first I thought that the birds were just always happy around me, but apparently it is actually the car. I am up to about 175,000 miles on the '04 S500 4Matic. I thought it must be the idler pulley, or possibly the tensioner pulley. It sounds as if it is coming from the right front side of the car. So I replaced the idler pulley, which did have a crack in it. No change. I replaced the tensioner pulley and put in a new contitech belt. The old tensioner pulley made a nice squeak when you spin it by hand, so it needed to be replaced. But alas, still the same chirping sound. The sound never seems to happen in first gear, only 2nd -4th. Usually at about 1500 to 2200 RPM and under moderate acceleration. If I coast the sound goes away, give it a lot of gas, the sound gets higher then goes away. I can even moderate the sound pretty consistently by using the accelerator pedal. It does not matter if I am turning right, left or going straight, always the same sound. Ambient temperature may have a slight effect, but not much, I hear it at 32 degrees and at 75 degrees. Possibly louder at warmer ambient temperatures. I am unable to create the sound while the car is parked, I seem to have to be moving. But the sound seems to be engine load based, not engine speed, or vehicle speed based. If I am coasting no sound, however, if I continue to go coast and go down a significant hill where there is reverse load on the engine, the sound will occur, but slightly muffled, while coasting if I apply the throttle just a tiny bit the sound goes away. While I had the belt off I did spin the alternator by hand, it spun smoothly and easily with no noise. I grabbed each pulley and tried to wiggle, none seemed to have any extra play. I am pretty much at a loss at what to look at next. Any help from the crowd would be great. I did look through the encyclopedia multiple times but I did not see a hint on what this might be. (doesn't mean it is not there, I just couldn't find it.)
I have a link to a video I took, depending on your browser it might ask you to download the file. (Red flag I know) I don't think you can upload video's as part of the thread.
https://www.wardells.net/sharing/9Fn7MU1Bf
Thank you for any help.
G.
I have a chirp. At first I thought that the birds were just always happy around me, but apparently it is actually the car. I am up to about 175,000 miles on the '04 S500 4Matic. I thought it must be the idler pulley, or possibly the tensioner pulley. It sounds as if it is coming from the right front side of the car. So I replaced the idler pulley, which did have a crack in it. No change. I replaced the tensioner pulley and put in a new contitech belt. The old tensioner pulley made a nice squeak when you spin it by hand, so it needed to be replaced. But alas, still the same chirping sound. The sound never seems to happen in first gear, only 2nd -4th. Usually at about 1500 to 2200 RPM and under moderate acceleration. If I coast the sound goes away, give it a lot of gas, the sound gets higher then goes away. I can even moderate the sound pretty consistently by using the accelerator pedal. It does not matter if I am turning right, left or going straight, always the same sound. Ambient temperature may have a slight effect, but not much, I hear it at 32 degrees and at 75 degrees. Possibly louder at warmer ambient temperatures. I am unable to create the sound while the car is parked, I seem to have to be moving. But the sound seems to be engine load based, not engine speed, or vehicle speed based. If I am coasting no sound, however, if I continue to go coast and go down a significant hill where there is reverse load on the engine, the sound will occur, but slightly muffled, while coasting if I apply the throttle just a tiny bit the sound goes away. While I had the belt off I did spin the alternator by hand, it spun smoothly and easily with no noise. I grabbed each pulley and tried to wiggle, none seemed to have any extra play. I am pretty much at a loss at what to look at next. Any help from the crowd would be great. I did look through the encyclopedia multiple times but I did not see a hint on what this might be. (doesn't mean it is not there, I just couldn't find it.)
I have a link to a video I took, depending on your browser it might ask you to download the file. (Red flag I know) I don't think you can upload video's as part of the thread.
https://www.wardells.net/sharing/9Fn7MU1Bf
Thank you for any help.
G.