muffler shield gone

[Benzomatic126]

I've been posting my mercedes questions for awhile on tech help about my 380 SEL; but this question could be about any car I suppose. (vw jetta)

I have a muffler in the rear of the car that has just "shed" its "outer layer" of metal (thin). Salt rusted it right off.the rest of the muffler looks very solid. Does this present a safety hazzard? I know most people will say "just put on a new muffler", but if it does not need one, I will pass until it falls apart.

Does anyone know their mufflers??

Thanks!

[Kestas]

The only function of this layer is to act as a heat shield. Was the shield facing the car or down to the road? If it was facing the car or some component of the car, then it's function is to keep the component from overheating. If it's facing downward, it's function is to keep the exhaust system from igniting dried grass of leaf piles should you happen to park over them.

This problem is more prevalent with cars that use 409 stainless steel - the cheapest grade of stainless - for exhaust components. The premature failures are typically cracks at the welds. Some of the better manufacturers use 300-series stainless which is less prone to problems at the welds, but is still susceptible to fatigue.

This is your VW Jetta? - of so - very common on the A3's for the outer skin to rust loose and you can peel it off with a little twisting and pulling. You can get another year or so out of the muffler before the rust starts eating a hole on the inner cover. With the outer cover gone the muffler still does not leak. The inner cover is much thicker than the outer cover, but it is not galvanized so about a year in parts of the country that use salt on the roads is about right. I've had this several times. The loose outercover rattles against the underside of the car and sounds bad, until you peel it off.

[Benzomatic126]

Thank you both for your replies. Yes Moedip, you are right on the money. I was twisting and pulling under the car until my shoulder got tired. Well, I guess I have a year.

Thanks again.