I hear rattling in my catalytic converter of my 1999 VW Beetle. Is there any danger in driving it?

SOURCE: where is the fuse box vw beetle 2003

As you see in the first illustration. you can use your key to pry open the cover. It may or it may not contain the fuse locator card.

SOURCE: my subaru forester has a rattle in the catalytic

I bet its just a the heat shield on the catalytic converter. Subaru uses very thin metal and the heat shield is bolted as opposed to welded together. This rattle is extremely common on subys.

mrmopar is right that you should replace it.

however there is a quick fix that will stop the noise. Go pick up a 6" stainless steel hose clamp at the hardware store. put the hose clamp around the cat. It should be obvious whats loose when you look under the car.

if you are a little handy its not a hard job to do your self. Just 4 bolts. You can get a catalytic converter for $200 online. Get the gaskets too. shouldn't take more than an hour or two.

You will need to put the car on jack stands or rhino ramps to get access. Once you are under the car, the parts are easy to get to.

Always, always chock the tires when your under the car. You do not want a car to fall on you.

SOURCE: 1999 VW New Beetle Coolant Temp Sensor

at the back of the cylinder head gearbox end it sits in the water pipe

SOURCE: 99 Isuzu Rodeo 3.2L 2wd Catalytic Converter instructions

you're having the same problem i had with my 99 isuzu rodeo 2 wd 3.2 i paid a muffler guy over $600 to replace those catalytic converters, if you're good at welding you could do the welding yourself after buying the catalytics, basiclly i seen them just cut them off and welded them back on

SOURCE: 98 VW Beetle 2.0L, Check engine light with OBD Code PO118

BTW - if you have less than 100,000miles you might be able to have your cat replaced under warranty by the dealer. In Canada it's 160,000km.