[urq] Rattle at higher rpm

[urq]

... if it could be coming from underneath the car I'd recommend the center
muffler ... the center muffler on my car makes a very similar sounding noise
at high revs.  There is some internal baffle that is loose inside.  I'd also
think about a cat heat shield, but you say that's already been swapped.

Steve B
San José, CA (USA)

-----Original Message-----

> For years I've had this annoying, fairly loud rattle - like a loose bolt
> or something, when I'm driving and the motor revs to about 4000+ and I
> shift.  This rattle has survived a motor swap and a cat swap.  It's
> definitely metal on metal and goes away as revs fall.  And it does not
> happen until the engine is warm/hot.  I'm thinking I need to get the
> engine hot, put the car up on ramps and carefull crawl under there (a
> little bit) and have somebody rev the motor.  Any other thoughts???
> Obvious places to look for something loose?  Maybe an odd bolt on the
> tranny?  Any BTDT?
>  
> TIA-
>  
> Brandon
> '84 ur

I too had a similar noise/problem (but temperature didn't matter). The noise
was really annoying, and really made the car feel 'wrong' when revving.

I couldn't find the problem until I pulled the head off to fix a blown head
gasket.

Seems as thought the starter heat shield had partially rotted away, and as
reves rose, it must have vibrated more. When I had the head off, I repaired
the heat shield, and after the motor seemd WAY smoother when revved up. I
never realized that was what was causing the problem, until I tried out the
car after the repairs. A 'bonus fix' as it were!

Could be some slack in the bolts the hold the downpipe to the exhaust/cat
too, I suppose...