Hi all,

 

I have an '89 120L, and it's developed this sound that's almost like a heat shield loose in the rear. It starts after the motor is warmed up, and during mid range revs. So idle is fine, and what passes for WOT is usually fine too. 

 

Any ideas? I thought maybe it's the exhaust rattling off the frame but it's not.

@Krtek How about the exhaust manifold heat shield?

Edited 18 May, 20179 yr by KenONeill

I'll have a look, I didn't see one since the exhaust is so short, but that's exactly what it sounds like. Odd that it only starts after warmup :p

 

 

@Krtek - I'd expect something because it's a non cross-flow head, but that's also why it's hard to see since the shield would be between the exhaust and inlet manifolds and under the carburetor and air cleaner.

If it's not the heat shields (which a lot of cars dont have anymore because they get left off when people work on the cars) it will be the exhaust baffles.....they come loose inside the silencer

@Krtek @petergarforth - Loose or broken exhaust baffles make a very specific "jingling" noise. This can probably be reproduced by slapping the box open-handed.

 

A recording of the sound (audio only is fine) would help if that doesn't work.

I figured it out; The 3 bolts that hold the manifold on were loose. 

 

I put my foot on the muffler when it was running, and noticed there was play there. Runs good as new. 

 

Thanks for all the help!