Collector pipes heat shield rattle

[Prplehz]

Ok here is the deal. My OEM collector pipes that go to the cat are covered by the OEM heat shield. Well that sucker has developed a nasty rattle on idle and acceleration, but then sometimes it just goes away all together. It sounds like the pipe is rattling against it on the inside. But I don't see how that is possible since the rattle wasn't there at all before and started after a decent freeway trip and it was never hit by anything to move things around. And it sure doesn't sound like the pipes are disconnected inside the shield. That would be obvious I would think from the loudness it would create in the exhaust sound. I thought it was the cat at first, but I took it off and it is new and rattle free so it isn't that. I checked all the bolts and they are tight, I even took them off and put them back on to be sure. Now I was going to just take the heat shield off and see if anything was inside it. Well if you have ever looked at one you know this is easier said than done. It doesn't just unbolt from the collector pipes. The metal is also folded over on the edges to keep it together. So to take it off you have to either bend back all those metal tabs, or cut the damn thing off. But I am wondering if I cut off the heat shield on the collector pipes, is the heat going to have bad effect down the road. I know that after market headers don't have a shield in that area, but a lot of those are also ceramic coated inside and out to stop heat transfer. I know I know just get a header and exhaust and enjoy the free breathing. But I want to keep it stock for now. Anyone been there done that and have any tips?

[SMP7MGTE]

You know who to call for a non-rattling, low mileage stock DP .....

[Dangerous Ken]

If it's an auto, check the clearance around the (auto tranny) dipstick too.

Ken

[Prplehz]

If it's an auto, check the clearance around the (auto tranny) dipstick too.

Ken

Yup, checked that. Everything has clearance around the pipes. I am sure it is coming from the insides. It sure is tough to tell where it comes from though. If I hold the pipes and hit it it sounds like the cat is rattling inside, but I had it off and it didn't rattle at all. If you hit the pipes you can hear a rattle, just can't tell where from.

[CarFreek]

After you replace it(take shawn up on his offer), you will find a rusty section of pipe inside the shield, probably some rusted scale making the sound.

[Prplehz]

After you replace it(take shawn up on his offer), you will find a rusty section of pipe inside the shield, probably some rusted scale making the sound.

Great minds think alike because that exactly what I was thinking it is. It just hasn't eaten through all the way through the pipe yet. Maybe even a piece of weld came loose from where the pipes connect and is twanging around in there now.

[Tanya]

Get a header :)

[Prplehz]

Well, turned out to be the cat after all. I took it off again and sure enough this time the insides were loose like a bunch of clay rattling inside. Cleaned it out proper like and put it back on ;) problem solved...

[84ptype]

cleaned it out as in hollowed it out??

thats proper lol

[Prplehz]

Yup. Well I didn't my neighbor kindly did before I could even get my hammer out, lol.