Has anyone had to replace their Catalytic Converter?
Thread Starter
Driver School Candidate
Joined: Dec 2009
Posts: 1
Likes: 0
From: NC
Has anyone had to replace their Catalytic Converter?
Trying to sell the car and get a newer GS for the wife. Of course once I decided to sell it, the CEL has been going on and off and eventually just stayed on.
and....the car is due for an emissions inspection.
Mechanic checked the code and said it was the driver side cat. Quoted something like $1500 or so plus labor.
Do I have to use OEM parts or can I go aftermarket? Are there any other workarounds anyone knows of? and...how can I check to see if its really the cats and not a gasket leak or bad sensor?
and....the car is due for an emissions inspection.Mechanic checked the code and said it was the driver side cat. Quoted something like $1500 or so plus labor.
Do I have to use OEM parts or can I go aftermarket? Are there any other workarounds anyone knows of? and...how can I check to see if its really the cats and not a gasket leak or bad sensor?
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
replaced one on my LS (same as GS) at a tick under 100k miles under warranty 
IMO it probably was a bad gasket creating the condition but the "test" said bad catalyst so the dealer just replaced of course with new gaskets.
I would first have the gaskets replaced. Relatively inexpensive. If in fact the cat is bad I would buy an aftermarket one and have a decent muffler shop cut the flanges from the stock one and weld in place in the correct position on the new cat. The cat itself should be well under $200 and the labor under that as well.
IMO it probably was a bad gasket creating the condition but the "test" said bad catalyst so the dealer just replaced of course with new gaskets.
I would first have the gaskets replaced. Relatively inexpensive. If in fact the cat is bad I would buy an aftermarket one and have a decent muffler shop cut the flanges from the stock one and weld in place in the correct position on the new cat. The cat itself should be well under $200 and the labor under that as well.
Lexus Test Driver
Joined: Mar 2007
Posts: 1,170
Likes: 2
From: New York
What codes are you getting exactly? I had a code for a bad cat, but after replacing an 02 sensor it went away and has not come back. Get the codes scanned.. autozone does it for free and post them up.
Rookie
Joined: May 2005
Posts: 68
Likes: 1
From: NH
1) Check the gaskets as jbrady says; common problem. If you feel exhaust air escaping then replace the gaskets or go to AutoZone or similar and buy some hi-temp cement and cover it up.
2) Check for exhaust leaks. Mine was uncovered when I removed the heat shield on the Y-pipe and where that was conected I had leaks. My mechanic welded some patches and never had a problem since. You might be able to use the cement there as a temporary fix until you trade the car.
3) Try switching your O2 sensors and see if the code moves with it. If so, then replace the O2 sensor that is bad.
All these are pretty easy to do/check before you sink in the money for a new cat.
2) Check for exhaust leaks. Mine was uncovered when I removed the heat shield on the Y-pipe and where that was conected I had leaks. My mechanic welded some patches and never had a problem since. You might be able to use the cement there as a temporary fix until you trade the car.
3) Try switching your O2 sensors and see if the code moves with it. If so, then replace the O2 sensor that is bad.
All these are pretty easy to do/check before you sink in the money for a new cat.
replaced one on my LS (same as GS) at a tick under 100k miles under warranty
IMO it probably was a bad gasket creating the condition but the "test" said bad catalyst so the dealer just replaced of course with new gaskets.
I would first have the gaskets replaced. Relatively inexpensive. If in fact the cat is bad I would buy an aftermarket one and have a decent muffler shop cut the flanges from the stock one and weld in place in the correct position on the new cat. The cat itself should be well under $200 and the labor under that as well.
IMO it probably was a bad gasket creating the condition but the "test" said bad catalyst so the dealer just replaced of course with new gaskets.
I would first have the gaskets replaced. Relatively inexpensive. If in fact the cat is bad I would buy an aftermarket one and have a decent muffler shop cut the flanges from the stock one and weld in place in the correct position on the new cat. The cat itself should be well under $200 and the labor under that as well.
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Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Rock, no, car felt the same. As I said I DOUBT the cat was bad just that was the "reading" and therefore Lexus blindly replace or CLAIMED to replace it??? I really do not know if they did or not. Could be easy money if they replaced a gasket and billed Lexus warranty division for a new catalyst.
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You have 'blockage' constantly. Having no cat, you'd have no blockage, which would increase exhaust gas flow....it's like installing a pair of headers on your car, less restrictive than the stock ones.
Now....it is illegal in some states to have a cat removed. It can actually result jail time if you get caught without one.
http://en.wikipedia.org/wiki/Catalytic_convertor
You have 'blockage' constantly. Having no cat, you'd have no blockage, which would increase exhaust gas flow....it's like installing a pair of headers on your car, less restrictive than the stock ones.
Now....it is illegal in some states to have a cat removed. It can actually result jail time if you get caught without one.
You have 'blockage' constantly. Having no cat, you'd have no blockage, which would increase exhaust gas flow....it's like installing a pair of headers on your car, less restrictive than the stock ones.
Now....it is illegal in some states to have a cat removed. It can actually result jail time if you get caught without one.
Also, do we (GS400 guys) have (3) separate cats or just (1) "3-way" cat?
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
GS400 has 2 cats one on each manifold (or header
) GS430 has 3 cats, two like GS400 and one center cat as the two pipes join.
The GS430 cats do not flow as high as the GS400 cats but they still flow well.
The stock cats are NOT a "blockage".
The metal cats are more durable than the ceramic cats but neither are likely to fail under normal use.
Here are some pics. First is a BMW metal core, next is a ceramic core, final is a damaged "clogged" ceramic cat.
You can take it to any competent muffler shop and they can drill a small hole before and after the cat and use a small pressure sensor to get readings. My Olds 442 had a bad power issue. The pressure was pegged before the cat and non-exisitent after the cap. I gained a lot of power back and my car didn't overheat anymore after cat replacement.
Are you saying that the GS400 cat are different than the gs430 cat? Or are you just saying the 430 is more restrictive because of the 3rd cat?
I noticed that OEM cat can possibly be modified to have a larger area inlet. I have an aftermarket header and wonder if I'll gain anything. It won't do any good if the 3rd cat is maxed out.
I noticed that OEM cat can possibly be modified to have a larger area inlet. I have an aftermarket header and wonder if I'll gain anything. It won't do any good if the 3rd cat is maxed out.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
Are you saying that the GS400 cat are different than the gs430 cat? Or are you just saying the 430 is more restrictive because of the 3rd cat?
I noticed that OEM cat can possibly be modified to have a larger area inlet. I have an aftermarket header and wonder if I'll gain anything. It won't do any good if the 3rd cat is maxed out.
I noticed that OEM cat can possibly be modified to have a larger area inlet. I have an aftermarket header and wonder if I'll gain anything. It won't do any good if the 3rd cat is maxed out.