Need advice re noisy catalytic converter

**Bud_wiser** · October 26th, 2012 12:59 AM

The catalytic converter on my car (1997 suzuki esteem) is rattling at certain engine speeds. It's become very annoying and so I brought it to Freemuff to see if tthey can fix whatever is wrong with the cat. According to the guy there, the rattle is from the inside of the cat and it can't be fixed. So he suggested that I have it removed and replaced with straight pipe.

what do you guys think about this suggestion? i don't want to remove the cat but I think my choices are limited. I don't know how much a new cat will cost and the noise is really becoming intolerable.

**ghosthunter** · October 26th, 2012 01:59 AM

Originally Posted by Bud_wiser

The catalytic converter on my car (1997 suzuki esteem) is rattling at certain engine speeds. It's become very annoying and so I brought it to Freemuff to see if tthey can fix whatever is wrong with the cat. According to the guy there, the rattle is from the inside of the cat and it can't be fixed. So he suggested that I have it removed and replaced with straight pipe.

what do you guys think about this suggestion? i don't want to remove the cat but I think my choices are limited. I don't know how much a new cat will cost and the noise is really becoming intolerable.

Options:

-replace your existing cat with a surplus unit taken from another car who had its exhaust system upgraded. Sometimes these guys just leave their stock exhaust systems at the muffler shop including the catalytic converter. You can check with some muffler shops if you can look through their "junk" pile for the catalytic converters from other cars.

-replace with brand new. Last time I bought one, it costed me P12K at Nodalos and that was many years ago.

- the noise is actually the content of the catalytic converter loose inside due to partial damage to the catalytic matrix itself. Imagine a sponge with a chunk removed. Our Honda City had the same issue. You can open up the can of the catalytic and remove the contents and reseal the can. Noise removed but catalytic is now just an empty can. Or you can have a metal wedge welded inside to hold the remaining chunk of catalytic in place, but this will only be a temporary fix because it will still continue to slowly crumble. Plus side, you still retain the function of the catalytic.

**niky** · October 26th, 2012 05:05 AM

A rattling cat is basically unfixable. You can slow down the degradation a little, but that's it.

Best to go for the surplus option. Scout performance shops, there are often a few discarded cats lying around. And most of them would be from 1.6 liter cars, so finding a good fit won't be hard.

**jick.cejoco** · October 26th, 2012 08:05 AM

Originally Posted by Bud_wiser

The catalytic converter on my car (1997 suzuki esteem) is rattling at certain engine speeds. It's become very annoying and so I brought it to Freemuff to see if tthey can fix whatever is wrong with the cat. According to the guy there, the rattle is from the inside of the cat and it can't be fixed. So he suggested that I have it removed and replaced with straight pipe.

what do you guys think about this suggestion? i don't want to remove the cat but I think my choices are limited. I don't know how much a new cat will cost and the noise is really becoming intolerable.

there had been cases with suzuki having the heat shield to the cat con rattling and making noise and there had been cases where the exhaust pipe were rubbing against the underfloor. try isolating the noise first.

**Bud_wiser** · October 26th, 2012 10:49 AM

Thanks for the replies everyone!

- The guy at freemuff told me that the rattle is from the inside of the cat, but I'll drop by nodalos to get a second opinion. I'd like to see if nodalos can open the cat and weld whatever is rattling in to in place, just to give me time to buy a new cat or look for a surplus one that will fit the car.

- Are there universal cats there that fit 2 inch diameter tubing? or maybe a free flowing cat for 2 inch piping? Just wondering, kasi I'm considering upgrading the exhaust system in the future for better performance.

- isn't the cat connected to the engine management system? Is there a sensor attached to it?

**jick.cejoco** · October 26th, 2012 11:41 AM

Originally Posted by Bud_wiser

Thanks for the replies everyone!

- The guy at freemuff told me that the rattle is from the inside of the cat, but I'll drop by nodalos to get a second opinion. I'd like to see if nodalos can open the cat and weld whatever is rattling in to in place, just to give me time to buy a new cat or look for a surplus one that will fit the car.

- Are there universal cats there that fit 2 inch diameter tubing? or maybe a free flowing cat for 2 inch piping? Just wondering, kasi I'm considering upgrading the exhaust system in the future for better performance.

- isn't the cat connected to the engine management system? Is there a sensor attached to it?

yes there is a sensor involved, the catalyst monitor (downstream oxygen sensor). without the catalyst, the malfunction indicator light will constantly be on.

**ghosthunter** · October 26th, 2012 12:40 PM

Originally Posted by Bud_wiser

Thanks for the replies everyone!

- The guy at freemuff told me that the rattle is from the inside of the cat, but I'll drop by nodalos to get a second opinion. I'd like to see if nodalos can open the cat and weld whatever is rattling in to in place, just to give me time to buy a new cat or look for a surplus one that will fit the car.

while you're at Nodalos, check their junk pile for a original catalytic from another car. You can pretty much use the any catalytic converter as long as the inlet/outlet pipe diameter is as least as big as your original exhaust pipe. That would be your long term fix for your catalytic. Don't worry if the cat you get is a bigger size, it would still work fine.

- Are there universal cats there that fit 2 inch diameter tubing? or maybe a free flowing cat for 2 inch piping? Just wondering, kasi I'm considering upgrading the exhaust system in the future for better performance.

The Nodalos cat I got had a 2inch inlet/outlet with very little backpressure. But generally, modern catalytic converters have very low backpressure so performance gain would be very minimal if any.

- isn't the cat connected to the engine management system? Is there a sensor attached to it?

Yes. If you don't reinstall the oxygen sensor, your car with throw a check engine light. Some cars, have two sensors located before and after the catalytic converter.