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MG MGF Technical - Clattering Noise

Yes it's me again. Sorry.

Being in North Wales I live on a steep hill. When I take my recently purchased 1996 MGF 1.8 down the hill with a cold engine there is a clattering noise from the rear. I can't really tell where it's coming from but it sounds like the exhaust. If I depress the clutch and roll down the hill there is no noise. When I get to the bottom of the hill and drive along flat roads there is no noise. When I go down a hill with a warmed-up engine there is no noise. It only seems to happen when I go down the hill first thing with a cold engine.

Someone from Sweden (I think) posted a message a while back about small 'explosions' when going downhill with a cold engine. Could this be the same thing?

Grateful for any advice. Thanks.
Keith Phillips

What kind of exhaust is on it?

If it's an aftermarket one then yes you'll get pops and bangs on coastdown regardless of going down a hill. And it's louder/ more noticeable when the engines cold due to more fuel being supplied my the fuel map in the MEMS (apparently, just what I was told) similar to a choke on a carb fed car.

It's not so noticeable on the standard zorst. In fact I never noticed it. Check whether the cat has been removed if its a standard exhaust. This makes it louder and you'd hear the popping and banging.

Nothing to worry about though especially if it only does it when its cold.

Its one of the reasons I love my Mike Satur Sprint exhaust.

the noise on coast down is fantastic!
Bob Millar

Bob,

Thanks for the response.

I am 99% certain that the exhaust is the original one fitted to the car when new. The flexi-pipe is not in great condition, but it definitely isn't blowing. The cat is definitely still there.

The noise disappears when I depress the clutch - would this be correct?

Thanks

Keith Phillips

- clattering ?
- depress clutch ?

Could be the clutch release bearing, may be.
Is there any noise when you press/depress the clutch when it just idles ?

Regards
Dieter
Dieter K.

Sounds to me like a pefectly normal overrun sound that occurs, through the exhaust, with a cold engine underload down a hill. Pressing the clutch would simply drop the engine back to idle, hence no noise. Is it a sort of pop, bang type noise more than a clatter (like mild backfiring?)
Karl Woodhead

Thanks very much for your responses.

There is never any noise when I press/depress the clutch when just idling. The only time it makes this noise is when going slowly down the steep hill on which I live when the engine is cold and the clutch is engaged. It stops as soon as I get onto the main road at the bottom (which is flat) and accelerate away.

There is a less steep hill going off in another direction, but I never get the noise when going down that one.

From inside the car it sounds like a clattering, but from outside the car it may sound like mild backfiring - it is difficult to tell - I will have to get the wife to run down the hill behind me!
Keith Phillips

I'd say then, don't worry about it at all, it's normal...my MG BGT with a mildly sporty cam shaft does it a lot...enjoy it!
Karl Woodhead

Hi

Could it be that the metal inside the cat is starting to work loose and rattle?

Simon
Simon

Keith, do you get the same noise if you head of up the hill instead of down?
Oil starvation?
jt
John Thomas

Forgot to post before that mine does excatly the same thing, when cold, when going down a steep hill slowly near where I live...my F is fine, goes well, no problems.
Karl Woodhead

Thanks again for your replies.

There is no noise when I go up a hill.

Following Karls' comment about his F when he goes slowly down a steep hill with a cold engine, I am going to assume that mine is doing the same as his. The car runs great otherwise so I am not going to worry about it.

Thanks everyone.

Keith Phillips

This thread was discussed between 29/05/2004 and 01/06/2004

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