Irregular interior rattle near rear seats

[the_old_diver]

Hi Friends,
My 96 Passat TD Umwelt saloon has developed a very annoying rattle which I cannot trace.
Symptoms:
It sounds similar to the noise made by a small spanner tapping on the rear window, or the noise made when the inertial seat belt mechanism locks up, or castanets.

I cannot make it happen by leaping up and down on the car when stationary, it doesn't happen at low speed on a smooth road, but occurs at rates of up to about 5 per second at higher speeds on bumpy roads. It is irregular, so a few seconds of silence might be followed by 5 or 10 rattles as the car moves up and down.

It seems to come from behind the driver's head, approx level with the top of the rear seats and in the region of the rear driver's side seat belt mechanism.

Already checked: I have removed the seat belt mechanism; I have investigated the filler cap locking mechanism and packed it with rags; I have checked the various linkages in the boot lid; I have weighed down and prised up the parcel shelf.

I am left wondering if there might be something in one of the pillars? Any pointers will be appreciated - it's beginning to drive me mad :-)

Thanks in advance, OD

[the_old_diver]

Well, I had a word with my local garage proprietor as I was collecting my 'new' Sharan and he said "check the suspension" so I did, and by shaking the top end of the coil spring I can replicate the noise, but cannot see what is moving.

Does anyone have any ideas?

Thanks, OD

[euroslap]

Worn top mount possibly?

[the_old_diver]

Thanks for the suggestion. I have studied the exploded diagram in the Haynes Manual but it is rather too exploded for me to make sense of. The bolts visible in the passenger compartment - next to the seat belt reel - are tight, and I don't have any coil spring compressors so I'm not sure what to check or how to check it.

If you have the time to flesh out your thoughts a little further it would be greatly appreciated!
Thanks, OD

[euroslap]

Thanks for the suggestion. I have studied the exploded diagram in the Haynes Manual but it is rather too exploded for me to make sense of. The bolts visible in the passenger compartment - next to the seat belt reel - are tight, and I don't have any coil spring compressors so I'm not sure what to check or how to check it.

If you have the time to flesh out your thoughts a little further it would be greatly appreciated!
Thanks, OD

I'm thinking it may possibly be the rubber mount underneath the three bolts. You'll have to drop it out to check though.

[the_old_diver]

Ah - thanks for that. Maybe I'll just have to buy me some spring compressors and grab the bull by the wossnames.
Cheers, OD

[euroslap]

Ah - thanks for that. Maybe I'll just have to buy me some spring compressors and grab the bull by the wossnames.
Cheers, OD

Thinking about it you should be able to drop the whole assembly down without a spring compressor and inspect.

[gerryb2]

Whilst you may be on the right track with suspension, I had similar noise in my Passat. Whilst under the car noticed loose bolt on exhaust heat shield. Tightened up - noise gone.

[the_old_diver]

Thanks Gerry,
I'll check that too. Car is presently road legal but resting in my garage until I summon the inner strength to try again to cure it! My 97 Sharan has a nice rattle from the front nearside susopension but I have traced that to a stripped thread at the top of the MacPherson strut, inside the engine compartment holding down the flying saucer thing. Damned if I'm going to replace the whole thing just for that - think I'll clamp a MoleGrip onto the screw above the nut to keep the show on the road.

Cheers, OD