Loud rattling noise

[dg4cars]

When I start up my Series 1 there is a loud rattling noise from engine compartment. Once the car gets above 10mph the noise disappears. Any ideas

[mike020150]

I think you need to give us a few more clues. Which model have you got? Which engine is fitted to your car? Does the rattling occur both when the engine is hot and cold? Does it occur when the clutch is depressed or engaged? Is the rattling from the front of the engine or elsewhere? Does the rattling cease when the car's at rest and the revs are raised? Mike.

[dg4cars]

Thanks Mike,

The car in question is a 1973 Series 1Daimler Sovereign Automatic 2.8litre .

Rattling from the engine compartment occurs on start up, cold engine 1000revs , speed below 10mph. It also appears when the engine is hot ie when parking car, speed below 10mph or revs below 1000.

Your thoughts please.

D.


2000 Stype 3.0 petrol
73 Daimler Sovereign 2.8 auto

[mike020150]

The fact that the noise is present (and the same?) hot and cold tends to rule against internal issues and leans towards pointing the finger at the components on the front of the engine. Chief among the suspects would be a failing belt tensioner. If you remove a belt, you can spin its tensioner wheel by hand to see if it rattles or runs roughly. Similarly, by removing each belt in turn and very briefly (you don't want to over-heat the engine running without a water pump) starting and running the engine, you would be able to hear if the noise stops and thereby you would be able to identify which component or pair of components is causing the issue. Alternators can rattle as well as their tensioner wheels so be sure to check both whilst you are checking the tensioner. Good luck with the diagnosis. Mike.

[davidr]

You might try several things that don't require any dismantling before you resort to the spanners.
Firstly try going round the car, from underneath as well if possible, banging things with a rubber mallet and listen for noises. That was how I found that the manifold heat shield was loose on my V12 XJS.
Secondly you could use a stethoscope to listen to bearings etc for loud noises.
If you don't have a stethoscope then a long screwdriver held against the offending part with your ear next to the handle does a reasonable job of amplifying noises.
Hope that helps
David

[dg4cars]

Mike and David,

Thank you gentlemen most sincerely for your replies.

Will investigate and update you on progress.

Interestingly I replaced the battery recently. The previous one was less than 18months old, perhaps this could point in the direction of an alternator issue ???????