Re: 240 rattles
"David Balfour" <email@example.com> wrote:
>> Take a rubber or rawhide mallet and get under the car. If yours is the
>> same as my 1990 you will find a curved, dual header pipe (tweo
>> parallel pipes as one) leading from the cast exhaust manifold towards
>> the catalytic convertor (if so equipped). Give the double pipe a rap
>> or two and you will probably hear the rattle.
>> CAUSE: this is a double walled pipe with an insulating layer between.
>> The insulation breaks down and allows the inner pipe (or the
>> insulation) to rattle together.
>> CURE: get some self-tapping sheet metal screws and install a few
>> through the outer pipe so they push against the inner pipe to stop
>> them from moving and thus rattling.
>Randy, many thanks for that - I'll take a look tomorrow. It does sound
>likely, as the rattle is absent when the car is cold. I don't really
>understand the magic behind these Volvo cats, but it could be this double
>pipe you speak of that's causing the problem.
The rattle has nothing to do with the cat itself but the pie that is a
ways in front of it.
The other likely places are:
1) The heat riser pipe (aluminum duct work leading from the heat
shield to the air cleaner box. These will vibrate and rattle against
body work which wears the pipe as well as the paintwork.
2) The heat shield around the cast iron header
3) The heat shield that is above the catalytic convertor (less
likely). In some cars the shield is bolted to the exhaust, in others
to the body.They sometimes can come loose and drop onto the exhaust
which can make a real racket. usually not so RPM dependent.
Randy & \ \/ /alerie's
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"