Background: '99 SLT 5.9L 87000 miles?About 8 months ago I replaced the water pump because the seal went bad and was leaking. Before it went I did notice a chirping sound. About 4 months ago I began to hear a chirping sound again that seemed to only occur when the D started up and was cold. It also seemed to get louder at higher humidity and after raining. However it always went away after warming up. I decided to replace the fan clutch which didn't solve the problem. Now the noise is getting worse. While in park I only hear the noise if I rev the engine. However when I put it into R, N, D the noise starts immediately. I'd definitely describe it more as a squeal than chirp. It does get louder and occur at a higher frequency when the rpms increase so I think it's in some component on the drive belt line. I replaced the belt tensioner and idler pulley last week but it didn't solve the problem. The belt is less than a year old and looks okay. I have noticed the temp running a little hotter this summer (~210 consistently.) Do you think it could be the water pump? With the belt off I spun all the pulleys and can't hear anything obvious. I'll try the stethoscope trick but it's pretty hard to pin point the sound. I don't think it's the A/C compressor because the noise isn't effected when the clutch kicks in. The clue may be in the fact that the noise starts up immediately when shifted out of park. I don't want to have to take it to the stealership! Help!!
-Ryan
-Ryan
