TCCoA Forums banner

1 - 11 of 11 Posts

·
Premium Member
Joined
·
1,244 Posts
Discussion Starter #1
Ok, a few nights ago, the Cougar started getting this really loud rattle on cold start ups. After about 5 minutes or so, it would go away, but tonight it got quieter although you could still barely hear it. It's coming from the driver's side and the best description I can give is a loud, pronounced, metallic rattle that occurs between 1200 and 1500 rpm. It sorta sounds like if you had a square piece of sheet metal welded to a frame on 3 sides and whacked the loose one with a hammer at the engine's speed.

Any ideas? I'm going to check the bolts that hold the manifold to my heads. The headswap was done about 7000 miles ago and there were no problems with this rattle until about a week ago.

Pete
 

·
02 Explorer Pioneer
Joined
·
2,880 Posts
sounds like the heat sheild on the catalytic converter. I have to tack weld mine every now and then
 

·
Registered
Joined
·
33 Posts
i have the same problem but only when its in drive at around the same rpm. when i free rev it its not there. i always thought i was one of the cats heat sheilds also, but why would it only rattle in drive and not when in neutral? :2huh:
 

·
Premium Member
Joined
·
1,244 Posts
Discussion Starter #4
When mine does it, it rattles in drive and when I rev it in neutral. The catalytic converters are Carsound high flows that went on in November when I built the exhaust. Where should I look on the heatshield to add some more welds?

Pete
 

·
Registered
Joined
·
324 Posts
BIG PETE said:
When mine does it, it rattles in drive and when I rev it in neutral. The catalytic converters are Carsound high flows that went on in November when I built the exhaust. Where should I look on the heatshield to add some more welds?

Pete
Just tighten a screw type band clamp around each cat-converter, thats the
standard/common fix for a rattling heat shield.

Chris..............
 

·
Registered
Joined
·
175 Posts
Also..make sure all your oxygen sensors are tight, especially the rear sensors (cat sniffers). Mine had a very similar rattle that sounded very much like a loose converter heat shield. When I hammered on the exhaust system or the cats, it even sounded like it was the cat because the sound resonates through the pipe making it very difficult to locate. It can be done easily from under the car with an adjustable wrench. Just make sure you don't slip and break the top portion of the sensor...
Hope this helps...

-DG-
 

·
Premium Member
Joined
·
1,244 Posts
Discussion Starter #7
Cool, thanks for the input, guys. I'll definately check on the O2 sensors and I will invest in a couple of monster hose clamps. All the suggestions are easy repairs and hopefully, they will do the trick.

Pete
 

·
02 Explorer Pioneer
Joined
·
2,880 Posts
I have aftermaket cats as well. If you look at the cat and tap the shield with your hand it will be pretty obvious. usually they are held on with 4 or 5 tack welds and one will let go allowing the two halves to vibrate together
 

·
Premium Member
Joined
·
1,244 Posts
Discussion Starter #9
Ok, I fixed it today. I went to the shop and bought the monster hose clamps and started to put them on when I noticed that the ratteling sound was still present from "higher" up the system than the cats. So, I checked the manifold studs again to the flange and the nuts were tight on them. But, as I was backing the wratchet out, I bumped the flange and it shifted and made the same sound as the rattle. It was rusted, so I think between getting rust in the threads and not having the flange straight, the nut was never really getting tights.

So, I dropper the front half of the system, cleaned the studs well and aligned everything as straight as possible and tightened the nut down on the stud this time. It seemed really solid and made 2 cold starts with zero rattles.

Thanks for all the input, guys.

Pete
 

·
Registered
Joined
·
11 Posts
I have the same problem with my '95 3.8 T-Bird LX. I just took it to a local Goodyear place, and they told me that I need to replace the whole converter (it's the original, believe it or not -- 70K miles) and the associated Y-pipe for around $950!

They also said that if the catalyst is breaking down inside the converter, it can plug up the whole exhaust system and cause driveability problems (although there don't seem to be any right now) and possible engine damage. Is this true, or just BS?/
 

·
02 Explorer Pioneer
Joined
·
2,880 Posts
BS sort of. It will lose power and usually smell like roten eggs when the cats go bad but I have never heard of damage from it. In addition for that kind of coin you could get a complete mandrel bent dual exhaust system with high flow cats from ART
 
1 - 11 of 11 Posts
Top