Annoying vibration

wiz043 · Postby **wiz043** » Wed Mar 27, 2013 8:16 am

I have a '99 NB and lately I have been getting a loud tinny metallic vibration in the engine at around 1,300rpm when starting from cold.
It seems to disappear as the engine warms up which may indicate the offending metal expands against whatever it is vibrating on to stop the noise.
It appears to be coming from the metal cowel area over the manifold but I have tightened the bolts securing this to no avail.
Just wondering if anyone has experienced this with their NB or have any idea what it could be.
It's driving me nuts as it sets up a real howl between 1200 to 1400rpm. :cry:

93_Clubman · Postby **93_Clubman** » Wed Mar 27, 2013 10:36 am

Usually heat shield securing tab breaks from the main body of the shield, so when you tighten the bolt it has no effect as tab is no longer connected to the shield.

wiz043 · Postby **wiz043** » Wed Mar 27, 2013 11:30 am

Is the top heat shield actually attached to the manifold by a weld? Also, are there other heat shields under the car at the front that are welded or bolted on?
If that is the case one of the welds may have let go and I should be able to remove the shield/s to check this unless it is welded in several places ??

Guran · Postby **Guran** » Wed Mar 27, 2013 12:01 pm

John, I'm happy to offer another pair of ears, eyes and hands over the weekend, if you'd like some help solving this one.

93_Clubman · Postby **93_Clubman** » Wed Mar 27, 2013 12:13 pm

wiz043 wrote:Is the top heat shield actually attached to the manifold by a weld? Ones I've seen have been bolted or clamped on. Also, are there other heat shields under the car at the front that are welded or bolted on? Yes, again bolted or clamped on.
If that is the case one of the welds may have let go and I should be able to remove the shield/s to check this unless it is welded in several places ?? Shouldn't be welded just bolted/ clamped in multiple places.

It's usually the header heat shield, but sometimes the others can cause the vibration issue.

wiz043 · Postby **wiz043** » Wed Mar 27, 2013 12:33 pm

Guran wrote:John, I'm happy to offer another pair of ears, eyes and hands over the weekend, if you'd like some help solving this one.

That would be great Bryan if you could drop in on the weekend sometime so I can start it when it's cold. Certainly sounds like a heat shield vibration.
Pls let me know of day/time to suit you.

wiz043 · Postby **wiz043** » Wed Mar 27, 2013 9:08 pm

wiz043 wrote:
Guran wrote:John, I'm happy to offer another pair of ears, eyes and hands over the weekend, if you'd like some help solving this one.

That would be great Bryan if you could drop in on the weekend sometime so I can start it when it's cold. Certainly sounds like a heat shield vibration but it's hard to check with one hand on the throttle.
Pls let me know of day/time to suit you.

Guran · Postby **Guran** » Wed Mar 27, 2013 10:28 pm

No worries. Will give you a call tomorrow.

wiz043 · Postby **wiz043** » Tue Apr 09, 2013 10:05 am

Guran had a look at it and said it appears to be a worn alternator belt making the noise so I was on the wrong track when I thought the drone was coming from a heat shield.

Replaced both belts and noise gone....thanks Guran... :wink: