Exhaust or cats rattle...
 

Hey Forum,


I have a situation here with my exhaust/cats system. I hope some of you might be able to help me give me some advice regarding repairs or perhaps a DIY fix...

My car is a Boxster 98, tiptronic, 143.000 km with stock exhaust system.

For the last 1-2 months my car has developed a rattle - In my opinion it has become worse over time, but maybe it has simply just become more obvious during the summer due because I have the roof down all the time.

I have a rattle from my exhaust/engine area. It's not constant and it's not a rotating sound, but very metallic and clattering. Its most obvious when the car is standing still and if I just tap the throttle lightly..

It gets better when it warm, but doesnt go away. Today I got underneat the car and took a water bottle and hit the two cats and that defenetly replicated the same metallic noise.... they weird part is the noise came wether I hit the left or right catalysator box so mabe the problem is not the actual boxes but something before the cats...

When I hid the exhaust tip the noise also appears, but not as loud so I think I am closer to the source of the rattle if I hit the catalysators.

The car drives nicely and I don't think it has lost performance or 'smoothness' when I accelerate.

I dont have a lift, and I am not very mechanical.. so I got these couple of questions...


But what should I do here?
- I read about hitting the cats with a happer when they are cold as a fix?
- I also wanted to hear if I can exchange one catalysator at the time or if they need to be changed as a pair?
- Any experience with the approx. costs of a catalysator exchange?
- I will have to take it to the mechanic, but before they simply say new cats I would like to know if there could be any metal/heat shields or sort of fittings/mountings that could have come loose they should check for - my mechanics have a history of just telling me to replace everything!


Thank you in advance!