Isolating Ticking/Rattle....Longish

[das boots]

Today was the first time that I travelled around our neighborhood with windows down due to the hot weather. This is the first time that I heard a ticking/rattle sound emanating from unknown area. I do not know how long this has been going on since the windows have always be up and sealed in.

The sound would specially be more noticeable when the side streets have high walls in which the sound would bounce around.

The ticking is similar to as if the fan would hit the fan shroud but quieter. And it is speed related. Would begin approx. 15 mph and higher.

No sound at idle. I tried to move in and out the pulley for the water pump but still solid. I will wait for a more complete cool down before I open up the reservoir to check for coolant level. Coolant temp has remained constant and would settle a few ticks before midway point when warm.

No trouble codes (knock on wood) signaling any problems.

Anybody have previous experience and inquiries or you can point to the area where I can start my troubleshoot. Thanks.



Edit: Had to add approx. 1 qt of coolant after the reservoir completely cooled. Coolant way below the minimum.

[Avetiso]

Check your exhaust clamps.

[das boots]

Upon further driving, the noise is really coming from somewhere undercarriage. And it is a rattle more than ticking upon further evaluation.

I will check the exhaust clamps. How many clamps are there? I know of the most rear clamp by the muffler and twin pipes. Would there be others?

[Johnmadd]

Does the noise go away when you push the clutch in?

[ELCID86]

rock in tire treads?

[LivesNearCostco]

The ZHP exhaust bolts up in 4 locations
1) To manifold with 4 nuts, 1 reinforcement bracket and 1 gasket
2) To transmission; clamp on pipes bolts to bracket on bottom of transmission
3) Cross-tunnel braces: Pipes sit on top of rubber mounts on one of the two tunnel braces
4) Muffler: two pegs hang from rubber supports in rear; each support secured on studs using 2 nuts

Loose at the manifold could create rattling and exhaust leak. Loose at the transmission bracket shouldn't cause rattling. Loose cross-tunnel braces could cause rattling, even if it's not the one holding up the exhaust. Loose at the muffler shouldn't cause rattling unless it's so loose the muffler or pipes to hit part of the suspension or body panel.

Loose heat shielding could rattle against body or exhaust--it's usually held on with 10mm speed nuts or 10mm bolts. The fuel filter protective cover or underbody brace could rattle if loose.

I've had rattling caused by loose pebble caught behind brake rotor dust shields. In this case it usually sounds different if you go in reverse, and you can often remove it by pushing the lower edge of rotor shield inward with a 3/8" socket extension to let the pebble fall out.

[das boots]

Vista BMW have courtesy BMW inspections everyday. My BMW mech works there as the supervisor mech tech. I will bring to him next week cor him to check the undercarriage out. It's free. Might as well make use of it.