Contour Enthusiasts Group Archives Forums General Troubleshooting Replacing Catalytic Converter

I went to the mechanic today to figure out what the vibrating noise on my car was. He said that it was the catalytic converter and since the car has less than 80,000 miles on it it is against federal law for him to replace it. He said to take it to a Ford dealer and they will replace it for free. My question is what is the difference between a cat and a catalytic converter, or are they the same thing?? I had the SHO cat and y-pipe installed on my car so if the cat and catalytic converter are the same, what should i do??

Yes, cat and catalytic converter are referring to the same thing. Unfortunately, we have 3 cats on our cars. If you've replaced the y-pipe and "main" catalytic converter, Ford wont cover the add-on parts under the normal, government mandated, 80K mile emissions warranty. If the SHO cat (under the car) is rattling, then you'll have to work with SHO for a warranty replacement. It might just be a loose heat shield which a muffler place could weld up for like $10.

Now for the other cats... The V6 also has 2 "pre-cats" These are built into each exhaust manifold, between the cylinder heads and the Y-pipe. If these pre-cats are rattling, BE CAREFUL! The stuff rattling around could get sucked into the engne and cause major damage. The pre-cats are also covered by the 80K mile emmision warranty, but the dealer will probably give you a hard time about covering them on warranty because of the custom Y pipe. (It's worth a try though....) These are real expensive to replace ($1000+) and many of us just "gut" them and remove the ceramic matrix thats inside the manifolds. (Search on mystery mod)

To see if your pre-cats are falling apart and rattling, try using a big screwdriver as a stethescope. Listen to the handle and put the blade up against the front bank exhaust manifold while the engine is running.

were you getting a rattling noise @ idle and around 2k RPMs? I am getting a terrible rattle from under my car. It seems like it is in the front between the two front doors.. I was planning on looking under it sometime to see what it was... It sounds like somebody is shaking rocks in a can or something.

Yeah, that's the kind of rattling I was getting.

Ok, found out the problem. I had a bad fuel system (which I told my mechanic that was the problem) but he didn't diagnose it until I came back a third time with a rattling catalytic converter. I got a new fuel system for $370 installed and he told me to take it to the Ford house to have the 80k mile federal emissions warranty work done to replace the cat for free. But since I have an aftermarket cat, it is going to cost me $180 at my trusty muffler shop for parts and labor (it is the same cat from the SHO shop). The cat's ceramic coating on the inside was killed when the bad fuel system started burning too much fuel inside the cat. So all in all it looks to be $550 for a f'd up'd fuel system.

Sounds like the brick broke up....

i had to replace one of those stupid precats. It is in the manifold i guess, because it looks like the replaced the whole manifold. The one in the front of the engine. I cant see what the did in the back, probably nothing. Now somebody mentioned that precats are in both manifolds?? What i was told on the dealer, that 2 precats come as one part, so they both had to be replaced. I gonna go and check that with them again.
Anyway, it was under warranty God, i'm so happy about that one, cuz it would cost me around $1000 to replace it.