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Catalytic Warrenty Question

smiledr996s

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smiledr996s Enthusiast

smiledr996s

Posted
Posted

I had a check engine code for a bad catalyic conv. I took it to a dealership and they had told me they were going to replace both. Although only one was replaced.

 

I was curious if anyone else had a cat failure and did the replace one or both?

 

Thanks

Steve

Whocares05050 Enthusiast

Whocares05050

Posted
Posted
I had a check engine code for a bad catalyic conv. I took it to a dealership and they had told me they were going to replace both. Although only one was replaced.

 

I was curious if anyone else had a cat failure and did the replace one or both?

 

Thanks

Steve

 

 

You only need to replace the deffective part. If only ones deffective than just the one side should be replaced.

Badass69 Senior Enthusiast

Badass69

Posted
Posted
I had a check engine code for a bad catalyic conv. I took it to a dealership and they had told me they were going to replace both. Although only one was replaced.

 

I was curious if anyone else had a cat failure and did the replace one or both?

 

Thanks

Steve

 

 

At right around 60000 miles on my old 06 1500HD I got a code for a bad convertor. The emissions warranty covered it and GM just changed the head pipe and convertor that had failed and left the other one. At 85000 miles I got a new truck and never had any other problems with the 06's cats...... just everything else. I wouldn't really worry about it.

c4cruiser Enthusiast

c4cruiser

Posted
Posted
I had a check engine code for a bad catalyic conv. I took it to a dealership and they had told me they were going to replace both. Although only one was replaced.

 

I was curious if anyone else had a cat failure and did the replace one or both?

 

Thanks

Steve

 

 

You only need to replace the deffective part. If only ones deffective than just the one side should be replaced.

 

 

If the cats are being replaced under warranty, it would have been at no cost to him so it's no big deal. But cats do fail after some period of time and it's usually the material falling apart from rust or corrosion. When that happens, it can clog the exhaust pipe or the rear of the converter and that can cause engine damage.

 

A good tech/dealership would have inspected both cats to see what condition they were in. Looks like the bad one was replaced and the other was probably good.

minibike132 Senior Enthusiast

minibike132

Posted
Posted
I had a check engine code for a bad catalyic conv. I took it to a dealership and they had told me they were going to replace both. Although only one was replaced.

 

I was curious if anyone else had a cat failure and did the replace one or both?

 

Thanks

Steve

 

 

You only need to replace the deffective part. If only ones deffective than just the one side should be replaced.

 

 

If the cats are being replaced under warranty, it would have been at no cost to him so it's no big deal. GM is watching our warranty parts closely. But cats do fail after some period of time and it's usually the material falling apart from rust or corrosion. When that happens, it can clog the exhaust pipe or the rear of the converter and that can cause engine damage.

 

A good tech/dealership would have inspected both cats to see what condition they were in. Looks like the bad one was replaced and the other was probably good.

 

 

Almost everything we replace is being called back to the factory for inspection. If they don't find a problem with it they are going to charge us back unless a good reason is documented. We have an emerging issues class every month and for the last year about half of every class has been dedicated to what happens when they call parts back and how to make sure we don't get a charge back.

 

But I agree, a good tech would have inspected both as well as looking for some key indicators on the scan tool data to verify that only one was bad. If both were bad they would have been replaced. They almost never go bad at the same time unless there was something catastrophic induced to the exhaust like a big coolant leak into both banks.

 

I don't think you have anything to worry about here.

smiledr996s Enthusiast

smiledr996s

Posted
  • Author
Posted

Thanks

 

I appreciate the replys. I was under the truck today, and it was kind of a downer to see a shiny new cat, and a rusty looking one. I have 10k to see if it goes.

 

Steve

Whocares05050 Enthusiast

Whocares05050

Posted
Posted
I had a check engine code for a bad catalyic conv. I took it to a dealership and they had told me they were going to replace both. Although only one was replaced.

 

I was curious if anyone else had a cat failure and did the replace one or both?

 

Thanks

Steve

 

 

You only need to replace the deffective part. If only ones deffective than just the one side should be replaced.

 

 

If the cats are being replaced under warranty, it would have been at no cost to him so it's no big deal. But cats do fail after some period of time and it's usually the material falling apart from rust or corrosion. When that happens, it can clog the exhaust pipe or the rear of the converter and that can cause engine damage.

 

A good tech/dealership would have inspected both cats to see what condition they were in. Looks like the bad one was replaced and the other was probably good.

 

 

 

I have seen converters last less than a day, and others last over 20 years. A converter will not go bad on its own. There has to be a known mechanical issue with the motor ( ie: raw fuel or a very lean mixture / misfire ) to cause a converter to go bad. Very rarely do you have a manufacture defective converter assembly. The only way to insepct a converter is one of two ways. You either tap on it and inspect it for loose debree / rattles ( meaning the converter is broken ) or you can cut the exhaust piping at the neck of the converter and see if it is clogged or has had a meltdown. To do the later of the two, the dealer would have to have a welder in there shop to re-weld the exhaust pipe if the converter checked good. Which could get a little expensive for either party.

 

If they replaced only one side, and the other they thought to have no problems, and there isnt any CEL or issues, than its fine what the dealer did. I install about 10 converters a week on various amount of diff makes and models and usually GM's only have one side go bad. Usually its the passanger.

minibike132 Senior Enthusiast

minibike132

Posted
Posted
I had a check engine code for a bad catalyic conv. I took it to a dealership and they had told me they were going to replace both. Although only one was replaced.

 

I was curious if anyone else had a cat failure and did the replace one or both?

 

Thanks

Steve

 

 

You only need to replace the deffective part. If only ones deffective than just the one side should be replaced.

 

 

If the cats are being replaced under warranty, it would have been at no cost to him so it's no big deal. But cats do fail after some period of time and it's usually the material falling apart from rust or corrosion. When that happens, it can clog the exhaust pipe or the rear of the converter and that can cause engine damage.

 

A good tech/dealership would have inspected both cats to see what condition they were in. Looks like the bad one was replaced and the other was probably good.

 

 

 

The only way to insepct a converter is one of two ways. You either tap on it and inspect it for loose debree / rattles ( meaning the converter is broken ) or you can cut the exhaust piping at the neck of the converter and see if it is clogged or has had a meltdown.

 

Or in a pinch you could check temp. Or you could do a back pressure test, which is the most reliable unless it is just falling apart. Or you could trust your 02 data. Or you could watch mass air flow, map and fuel trims on accel, a clogged one tells itself pretty easy watching those things.

 

I have never cut open a converter for any reason other then I was curious as to what the inside looks like.

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