I've had two separate unrelated drivetrain noises. I've had both for at least a year or two, probably more. Anyway driving today I've noticed strange things about them, strange enough to make a thread.
1. I've got a rattley, diesel truck sound at idle. First thought it was an exhaust shield, then noticed it goes away when I push the clutch in. Then I thought it was obviously the pilot or throwout bearing. After my clutch job it's still there. Same thing. I then thought, well either it's normal, or it's the supposed noise related to lightweight flywheels, or I've got a bad pilot / TO bearing again(both replaced so unlikely).
This morning I turn off the AC at a light, the noise goes away completely. Hit the AC button it's back full force. Push in the clutch pedal, noise goes away, let off the clutch, noise is back full force. Now it's got me head scratching...what the hell would be related between the clutch and the AC system? Any ideas? (edit to note: I also have an exhaust shield rattle, I've got a broken bolt on the bracket that holds the pipe after the header, but it's a seasonal, louder, more abrasive noise. This diesel sound at idle is reliably there, and reliably alternates with the AC button and clutch.)
2. Seems like my car has always had a SSSSSSSSSS noise while at speed. Not real loud, but annoying and can be heard above the road noise on quiet pavement. Sounds exactly like someone filling up a tire or helium ballon, that hollow hissing/ringing sound. Sounds like it's coming from the rear. I always figured it was a loud diff or some drivetrain part combined with miata style sound deadening. Today at lunch I notice the noise completely goes away when I apply the brakes. So pulled the hand brake slightly and same thing, goes away.
Naturally I would think i've got the rear brakes adjusted too tight and need to loosen them...but actually quite the opposite. I think they're not tight enough, my hand brake barely works in driving, and with it cranked all the way on an incline I can push the car and the brakes creek and almost move. (note the lever is adjusted to around 6in of movement, not too loose or anything) Noise has been the same through the crappy no-name Vatozone pads the car came with, the OEM value pads, and now Hawk HP street pads. Any ideas? Probably the adjustment isn't right and the pads are dragging, but I followed the procedures to adjust them exactly, and still the same, both noise and crappy hand brake.
Sorry for the novel of a post, I'm stumped on both of these and figured I didn't want to make two threads.
