Exhaust Noise

[jdro1978]

There is a strange rattling noise coming from the exhaust of my MK4 Golf.  I have been underneath the car and I thought the problem was a loose bracket or something, but the problem seems to be coming from inside the exhaust system (It’s from the box near the front end of the car – is this the CAT?).

I really don’t want to buy a new CAT – is there another solution?

John  

[kniterider]

my mk4 makes a louder tone when its cold till its warmed up, this tone seems to come from the cat area (the 1st silencer you see with a heat shield on it) as soon as the cars warmed up it goes away so im assuming its a joint or something that expands when it gets warm and deadens the tone, cats arent cheap if it is yours thats gone, try europarts or gsf to source a new one if its blown, or get it repaired and get a cat bypass pipe and save your repaired cat for mot time!, may give ya a few bhp more also! , havent tried it yet but if my cat is suspect thats what ill be doing!

[kniterider]

oh yeah forgot, some times the element inside the cat comes loose this will give you a ratteling noise, if so its time for a new 1!, get your wallet out !