We have a very annoying rattle. It sounds like metal-to-metal or plastic-to-metal, somewhere right rear.

It's there every AM, but goes away after 3-4 miles, only to return the next day.

Any ideas?

 

Try to include year, trim level and mileage in posts as it helps.

Exhaust system? Have you tried to get your head under the car to hear it directly?

Get another set of eyes and ears on it.

 

2004 V70, 135 K miles

Exhaust system checked hot and cold, no rattle. Mechanic kept it overnight, could not find. Checked trim. lights, gas fill, rear seats, rear wiper, items under rear deck, license plate, windows, rear brakes, wheels, parking brake, Still there. Can't put head under car, only rattles when moving.

 

Shocks....perished suspension bushing....worn spring seat....busted spring?

 

The mechanic checked all those things while he had it on his rack. He visually inspected, pushed and pried all moving parts.

The clue is, somehow, it only does it for the first few miles after sitting overnight. And it happens going straight down a smooth road, no particular bumps, tar strips, potholes. It sounds like something loose/flopping around or rubbing.

 

Do you use a hearing aid? Sometimes their effect can mislead.

A tool (socket?) dropped into a cavity or box frame element?

Get a 4-5 year old child and put him the back seat to listen. A kid can bend and twist about and possibly zero in on the source.

And you're saying there's no physical stimulus you can give your car (bumpy roads etc.) to cause this noise?

 

I'm saying that the noise is present when the car is first driven after sitting overnight. It goes away after 3-4 miles and does not return until the next day. So, no it is not a dropped socket, rough road, loose bolt, coke bottle or any other simple loose, rattling bit. The fact that it goes away made me think exhaust system, expanding as it heats up, but cannot find any rattle there when the car is parked and cold. It happens running over small bumps in the road, but after driving a few miles completely stops. Noise is right rear and exhaust system is on left side.

Applying brake does not change noise, so it is not a brake pad rattle or rusty rotor.

I have sat in back with my wife driving and the noise is somewhere behind, in the general area of gas fill door. Releasing fill door does not change noise.

'tis a mystery.

 

I'd look at the heat shield including at the fire wall - pin pointing sounds from the inside can be hard to do. Could also be inside the exhaust itself - piece of metal that rusted off inside the pipe etc. You can try cold starting the car then tapping the (cold) exhaust with a rubber mallet or similar to see if you can make it rattle.

 

Do you have the nivomat rear shocks? They could be bleeding down over night and pumping back up when you start driving.

 

A muffler has "internals" which can break loose, as mentioned above.

If you get yourself the pop-rivets and larger size pop-rivet gun you can drill out the rivets holding the fender liner easily enough and look at the filler neck, the fuel system's air intake rain check (or whatever it is called) and grounding strap.
It's all behind the fender liner.
NOTE: Many "household" sized guns come with an assortment of collets which simply unscrew to change. You needn't buy the gigantic set.
Just get one with the set of collets.

 

I have a v50 same thing back right did you manage to find what it could be

 

could be eBrake shoe delaminated. You'll have to pull the disk to find out.