Mysterious noise that quickly goes away??!

Hi all,

Defender 110 200tdi 1992 csw.

Recently had new clutch, refurbed alternator, both belts replaced, and fan cowl removed.

The issue is that every time I start her up, morning and night, as soon as I begin driving in 1st, there is a very metallic rattling which increases with speed/ revs, and after I get up into 2nd, the noise get's quieter and quieter and after a couple of hundred metres it always vanishes! I can stop at lights, change gears up and down etc, but the noise doesn't return).

The noise is very loud and can be heard over the stereo. It sounds like somebody is literally underneath the vehicle tapping a spanner on a drainpipe at a speed which increases as I drive. It is hard to be sure, but sounds like it's coming from under the front middle seat, so I'm assuming something's gone amiss with the prop or UJs, I greased them a fortnight ago and they looked to be in fine condition.

Any ideas?

Does it do it on fast tick over before you've pulled away or only when it's moving?

Ive had something like that recently, turned out to be a crack on the front down pipe exhaust, on the top, where you cant see it, after the bend. found it first by removing cubby box and middle cover and having a look, then getting me hands dirty and having a good feel.
i think the crack started to open up as the exhaust warmed up. worth a look.

XRIZLAX said:

Ive had something like that recently, turned out to be a crack on the front down pipe exhaust, on the top, where you cant see it, after the bend. found it first by removing cubby box and middle cover and having a look, then getting me hands dirty and having a good feel.
i think the crack started to open up as the exhaust warmed up. worth a look.

Click to expand...

A crack like that can come from driving through a deepish puddle ...

funny things cars ...

I started to type check the exhaust, but then changed my mind

Well I drove to work this morning, and the noise didn't happen.

Something's that's crossed my mind is that I reverse park into a space at work and so when pulling off I wonder if there is some kind of wind up or transmission problem that's being taken up for the first hundred metres or so?

I'll get underneath her on the weekend. (...and the landy ;-)) and see what I can see.

if you have engine at tickover and stood still do you get this tapping and if you raise revs does it go or by pressing clutch pedal?

Just to confuse matters; I started her up for work this morning with baited breath to listen to the noise, but lo and behold, it didn't happen. Then this evening when I finished work, I jumped in to drive her home, and again, it didn't happen. I'm still going to have a good nose around underneath on the weekend so will report back then.