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MG MGF Technical - Worrying sound...

Evening,

On the way home tonight I had a worrying sound... I went round a roundabout and as I came off it started. It was like stones rattling around underneath the car (or definately from behind me) but continuous when I was going fast and then died down as I went slower. I pulled over and couldn't see anything obvious but when I continued the noise came back...

There was a worrying archive post about the cam belt tensioner!

Any ideas?

Chris
Chris Tromans

Hi! Chris,

Put my "f" in for its 45,000 mile service to my
trusted garage and mentioned that a similar nose
to what you were experiencing. Looking at all the
dials, the temps and oil gages were steady when driving along, water and oil levels looked at and ok.

Went to collect the car, everything ok, but he discovered the baffle had gone in the exhaust (which
made it sound like a whole load of loose spanners in
the back) which is an MOT failure, so that could be
your problem as well! More expense and now looking
for the best quote on a replacement.

Bill
W.A. Pearson

Few more details as I was driving in this morning...

1.Its definately louder as I go up through the rev range in the lower gears...

2.While going along if I put the clutch pedal down and take my foot of the accelerator the noise goes away until I lift the clutch and put my foot back on the accelerator again.

3.It's definately slightly audible when the car was in neutral on my drive and just idling

Still look like the exhaust baffle?

All the temp needles look fine, coolant looks fine...

Chris
Chris Tromans

To rob bell...

Rob, in an archive post you said "Yes, I'd agree with that Ted, and also increased 'crakling' on over-run too."

Thats what this sounds like on my car... crackling...

Does this help?

Chris
Chris Tromans

Generally, when troubble-shooting as in your step 2, you would want to know whether the noise has to do with the driveline after the clutch or with the engine revs itself.

Try to rev up to the same revs on standstill with clutch down. If you get the noise then, it has purely to do with rev. For instance, the exahaust could be the cause.

I cured some rattle like that yesterday that was because of a worn flexipipe in the exhaust. (tightened some hose clamps...)

cheers
Oskar
O Sander

I'll do that tonight Oskar... also plan to jack it up (got to be the 10th time this week!) and take a look at the exhaust system and fiddle around with it..

Cheers

Chris
Chris Tromans

>> 2.While going along if I put the clutch pedal down and take my foot of the accelerator the noise goes away until I lift the clutch and put my foot back on the accelerator again. <<

I'm a little worried that this is gearbox noise Chris?

But still possible that the noise is coming from the exhaust - be that the flexi pipe, the cat or a loose baffle in the silencer box.
Rob Bell

Hi rob,

It certainly doesn't sound like the gearbox noise like I had on my old Rover k series when the main bearing had gone...

And I'm sure, but I will check as Oskar says, that if I put the clutch in and rev at a standstill then I do get the noise. That would point away from the gearbox wouldn't it?

Any major gearbox problems would hopefully be covered by my personal warranty I have.

If I can't see anything wrong with the exhaust tonight then I might pop it over to MGOC or MGR to get their opinion on whether it is gearbox related...

Cheers

Chris.
Chris Tromans

Problem solved... I saw it last night and MGR backed me up this morning... the alternator belt had shredded two bits in two places around the belt and the bits were hanging off slapping against bodywork etc... its now replaced and all is fine...

Chris
Chris Tromans

This thread was discussed between 13/07/2005 and 15/07/2005

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