Annoying Rattle

[Blackcat57]

Hi all,
My 93 240 estate has an annoying sporadic rattle coming from the front end. It tends to happen more on smaller bumps and rough road surfaces and strangely enough when going downhill. It still happens when the brakes are applied so don't think it's pads or calipers, and when cruising out of gear. It's not a clonking noise it's a metallic rattle but have looked all round the suspension and engine bay and can't find nothing loose. The car's in great condition and drives perfectly so this one small fault is particularly annoying. Any of you guys got any ideas?
Cheers

[Davey240]

Not sure if it's the same on all models but mine has a flexible metal pipe/duct which comes from the exhaust into the engine bay. Not certain of it's exact function, think it's some form of preheater. I had a 244 years ago which had the annoying rattle similar to the one you describe and that was the cause. Might be worth a look if you haven't already ruled it out as the cause?. Dave

[Blackcat57]

Thanks Davey240 but tried that. Took it off but the rattle was still there so put it back on. But it sounds like the sort of metallic noise that would make. Also tried removing the heat shield on the exhaust manifold. It wasn't that either.....

[Stephen Edwin]

Seek and hope that ye shall find....

One possibility is the support bracket for the inlet manifold. On my 1992 SE the bracket is screwed to the manifold. When I overlooked to replace that screw the noise was as you describe. I guess it is screwed to the car body. Are the securing screws in place and secure?

Ah. Yes. Our old friend the ducting from the exhaust area. It [usually or always?] goes to a valve in the air filter housing to aid cold running. If the valve gets stuck the air mass meter receives hot air for the entire journey. Many people remove the valve and disconnect or remove the ducting. Fried air mass meter is an expensive breakfast.

[Blackcat57]

Hi Stephen, where is this manifold support bracket you mentioned? Mine too is an SE spec car so I suspect it has the same bracket but I can't recall seeing it...

[Stephen Edwin]

The support bracket is held to the underside of the inlet manifold by a machine screw. Not easily noticed by me unless working in that area....

[BrianH]

My rattle was the nearside front swing arm rear bush.

Spent too much time replacing these over the years

Then I discovered it was the reusing the lock nuts on the rear bush

I got the Volvo washer and the Volvo squashed lock nut

Never a problem again

Go over bumps with the near side wheel and note the rattle, this may give you a clue

Brianh 650k LPG

[Clifford Pope]

Front-end rattles I've experienced over the years:

Brake pad retaining pins rattling in a rusty caliper.
Worn rubber anti roll-bar bushes on the chassis rails.
Washer bottle not restrained properly.
Radiator overflow tank vibrating against the front face of the suspension turret.
Bracket holding the horns flexing.
Radiator loose because the rubber pads are worn or missing.
Heat-shield cladding around the exhaust down-pipe vibrating (But see my previous thread - no one else seems to have this peculiar spot-welded clading running from the manifold flange all the way to the cat flange)
Mysterious black plastic canister mounted under the valance on the LH side loose.
Broken anti roll-bar link - although that tends to make a twanging noise as the two ends foul each other.
Brake dust shield flapping about because it's collapsing from rust.
Bracket holding the unions connecting the flexible brake pipes to the metal broken away fom the mounting.

Any other rattle from anywhere in the car - noises get transmitted so that they deceptively appear to come from far-removed locations.

[Blackcat57]

Thanks Guys,
Plenty for me to be getting on with there. I'm becoming quite obsessed with this rattle and am on a personal mission to track it down. It'll not get the better of me.......

[Clifford Pope]

One tip is to get someone else in the car to try and pinpoint the souce. A passenger often points to a completely different location from the drive.

I remember a persistent rattle that I could have sworn came from inside the passenger door. But a passenger instantly pointed out that the interior mirror mounting was vibrating because the screws were very slightly loose.
A noise I was sure was a rear suspension bush squeaking was actually the passenger side footwell cover. A noise of marbles rolling about in the boot was a front top suspension mount.
And so it goes on - good luck