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knocking noise

Posted: 19 Jan 2010 01:10 pm
by rems
hi all

hope you can help, i have a knocking noise coming for the prop as it spins i was told its nothing major and its something that needs changing but cant remember what they said :roll:

any ideas?

cheers

Re: knocking noise

Posted: 19 Jan 2010 02:18 pm
by volvosneverdie
might just want a reballance?
Does it get worse at higher revs?

Re: knocking noise

Posted: 20 Jan 2010 01:56 am
by Ride_on
According to other posts of your you have a 1.7, so the prop itself has no moving parts. Try it with the clutch in, and then with the clutch out and the gearbox in neutral. That will give some further indication as to the location. I'm guess it does it in Neutral with the clutch out, but probably stops with the clutch in.

Also under the car with the engine off there should be little backlash or movement of the prop at the clutch input shaft. Just try to rock it back and forth to check if there is any rotational or sideways looseness.

Another thing to do is compare it to another similar car. The the drive bearings in these cars are always a bit noisy if you listen for it outside the car.

Re: knocking noise

Posted: 20 Jan 2010 01:36 pm
by rems
Ride_on wrote:According to other posts of your you have a 1.7, so the prop itself has no moving parts. Try it with the clutch in, and then with the clutch out and the gearbox in neutral. That will give some further indication as to the location. I'm guess it does it in Neutral with the clutch out, but probably stops with the clutch in.

Also under the car with the engine off there should be little backlash or movement of the prop at the clutch input shaft. Just try to rock it back and forth to check if there is any rotational or sideways looseness.

Another thing to do is compare it to another similar car. The the drive bearings in these cars are always a bit noisy if you listen for it outside the car.
yea it happens in neutral when im sitting still but when im driving it goes away

Re: knocking noise

Posted: 20 Jan 2010 04:47 pm
by volvodspec
clutch release bearing

Re: knocking noise

Posted: 22 Jan 2010 08:39 pm
by Ride_on
The clutch is also out when you drive off so why would the gearbox being in gear affect it?

Does it go away when you put the the clutch in?

Can't think why it would do that other than rotational looseness.

Re: knocking noise

Posted: 28 Jan 2010 12:18 am
by rems
yea it goes away when i put the clutch in and im in gear

it only happens when in sitting still not in gear :?

Re: knocking noise

Posted: 29 Jan 2010 02:14 am
by Ride_on
Sounds like general looseness in either the clutch shaft bearing or gearbox front bearing.

I suggest comparing it to another 340 to try to determine how serious it is. They do make a bit noise if you listen for it.