What can I do about a Catatlytic Converter heat shield rattle?

[stumpjumper]

my rear most passenger side cat has a rattle, it is definately the shield though I don't know which part exactly

replacing the cat is obviously cost prohibitive unless it's somehow covered under my CPO, though I doubt it would be

having replaced the muffler myself I'm not afraid of getting under the car and working on it

[Loren]

Check your emissions warranty - it is usually much longer than the rest of the car. I think my MY99 California Emissions Warranty is 7 years / 70,000 miles.

[mikefocke]

986 or 987?

Known problem with 987s and there is a TSB fix for it.

Emissions waranties are different in CA from the rest of the US so read your warranty book and make sure you know what Porsche should pay for and what you should.

Since you have a CPO, read the CPO document.

[stumpjumper]

986 or 987?

Known problem with 987s and there is a TSB fix for it.

Emissions waranties are different in CA from the rest of the US so read your warranty book and make sure you know what Porsche should pay for and what you should.

Since you have a CPO, read the CPO document.

thought it was obvious since I'm in the 986 forum :)

about the emissions warranty, would the heat sheild rattle still be considered a faulty part even though the internals still work? I can see both sides to that argument so I just want to be prepared :)

I'll go read my CPO papers tonight, I should be as versed in them as possible anyway

[986Jim]

Get under the car, rip off head shield. Proiblem solved.

No you do not need the heat shields, they ave commonly removed on lots of cars (including Porsche) with aftermarket Cats and the like. There is little need for them and they always come loose and rattle in the end.

Manufacturers are forced to place them there as part of some horse**** safty rule from the DOT. As if the heat from the manifolds / exhaust pipeing before the cat is less than the cat and it really needs a shield or something.

[Q-Ship986]

Get under the car, rip off head shield. Proiblem solved.

No you do not need the heat shields, they ave commonly removed on lots of cars (including Porsche) with aftermarket Cats and the like. There is little need for them and they always come loose and rattle in the end.

Manufacturers are forced to place them there as part of some horse**** safty rule from the DOT. As if the heat from the manifolds / exhaust pipeing before the cat is less than the cat and it really needs a shield or something.

I would not remove a heat shield that was protecting the underside of the car or any component, particularly those of rubber or plastic such as a wheel molding, tire, engine mount, control arm bushing, etc. If the shield is protecting the ground, it can be a fire issue (i.e. if you ever park on grass). Catalysts get extremely hot by design (yes, hotter than the inlet/outlet--chemical reaction(s) are occuring within), and shielding is effective at reducing/redirecting the radiation.

Don't know about the warranty coverage, but I would think it would be a nominal fee to tack weld it back into place. --Brian

[manud]

my rear most passenger side cat has a rattle, it is definately the shield though I don't know which part exactly

replacing the cat is obviously cost prohibitive unless it's somehow covered under my CPO, though I doubt it would be

having replaced the muffler myself I'm not afraid of getting under the car and working on it

Had same issue on my 986. The heat shield is replaceable without changing the catalytic converter and is very cheap (around 15€ including labour)

[986Jim]

I would not remove a heat shield that was protecting the underside of the car or any component, particularly those of rubber or plastic such as a wheel molding, tire, engine mount, control arm bushing, etc. If the shield is protecting the ground, it can be a fire issue (i.e. if you ever park on grass). Catalysts get extremely hot by design (yes, hotter than the inlet/outlet--chemical reaction(s) are occuring within), and shielding is effective at reducing/redirecting the radiation.

Don't know about the warranty coverage, but I would think it would be a nominal fee to tack weld it back into place. --Brian

That’s all well and good, except for the fact that shops have been removing them or never using them at all in performance applications and never has there ever been a problem with this. As a matter of fact on many aftermarket exhaust systems there his no heat shield for the header cat or muffler. The header is the hottest part of the exhaust and a lot hotter than the cat, and it doesn't cause any problems with no heat shield. The heat shield is only on the top part of the cat as well, so it's not protecting the tire, wheel molding engine mounts or any other rubber part from the heat. Heat radiating from the exhaust components are not anywhere near the melting point of urethane or even rubber for that matter. If rubber were to touch the pipe, yes it would melt, but radiated heat through the air from exhaust will not effect these components what-so-ever. And really, have you ever seriously heard of grass catching on fire from a car parking on it? Yeah me either.

So, what you do is rip off the heat shield because we know that it doesn't cause any problems and also doesn't cost any money to do. Voila, problem fixed for free.

Edited September 29, 2006 by 986Jim

[stumpjumper]

manud thanks, I wouldn't have thought it was replaceable but after looking more closely it's simply bolted on and the bolt had come loose :)

I'd thought it was welded on like most I'd seen and figured I'd just have to remove it and bring it to a welder to fix it

[Q-Ship986]

manud thanks, I wouldn't have thought it was replaceable but after looking more closely it's simply bolted on and the bolt had come loose :)

I'd thought it was welded on like most I'd seen and figured I'd just have to remove it and bring it to a welder to fix it

This was the right thing to do. Other than the reasons I gave above, another reason to keep it is that catalysts need the right temperatures to operate as intended. Too much heat, and the cat can burn up. Not enough heat, and it doesn't do it's job. Sometimes a heat shield isn't a shield, it's a blanket to regulate heat loss. This, and the above, general information comes from contact over the years with actual vehicle manufacturers; FWIW, YMMV, and all that. --Brian

[986Jim]

[This was the right thing to do. Other than the reasons I gave above, another reason to keep it is that catalysts need the right temperatures to operate as intended. Too much heat, and the cat can burn up. Not enough heat, and it doesn't do it's job. Sometimes a heat shield isn't a shield, it's a blanket to regulate heat loss. This, and the above, general information comes from contact over the years with actual vehicle manufacturers; FWIW, YMMV, and all that. --Brian

Wow, regulate the heat hahahah.. Good one. First time I have heard that before.

Sounds good, except for the fact that this is not what it's for. THe cat doesn't need to be regulated, and can operate over 2500deg with no problem which it will never get too. THe monolith is platinum and ceramic. They dont melt at low temperatures of exhaust. The heat shields are only to redirect small amounts of radiated heat and are totally un-necessarry and can be removed with no problems. Brian I understand what your saying and where your coming from however, what your saying is simply not true.

Either way stumpjumper, I'm glad you got it fixed. In the future if you get a performance exhaust you need not worry about heat sheilds or anything as again they are not needed so don't go out looking for a system with them because they don't exist, again for obvious reasons. I have pulled the heat shields and cats for that matter off 911 TT with 600whp that are daily driven and tracked quite often. Absolutly no problems with them ever. They even park on grass at the track between rounds while racing too. If you found the problem and decided to keep them, no problem no harm in being 100% oem, however don't keep them because you think they are doing anything for you.

Regards,