2011 GMC Terrain - Oil Consumption Killed My Cat

muskie

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May 26, 2011
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2011 Terrain SLE2 - 102,XXX miles

In May I began oil consumption tests at Jennings Chevy in Glenview. The first few checks they said were "within spec", they topped my oil level off and sent me on my way and to come back in 1000 miles. My Service Advisor recommended some more highway driving to reproduce the problem. Sure enough next check I was more than 1.5 quarts low in less than 1000 miles.

There were two special policies that were in place 12313B and 15285C which replaced the pistons/rings, timing chains and high pressure fuel pump. At this time I had the spark plugs done due to my concerns of them being fouled as well as them being original. This was done at no cost to me.

Fast forward to last week and I now have a CEL on the dash. My first thought is something related to the repairs so I go back to Jennings. The code ends up being P0420 (Catalyst System Efficiency Below Threshold (Bank 1)). They want $1280 to replace the cat. When asked if it was related to the oil consumption issues I was basically told there is no way to determine that is what caused it to fail and it will not be covered under warranty.

My questions to TCG

1) 102,XXX miles seems very premature for a cat failure. Is this normal? In my opinion it has to be from the oil consumption issue.

2) This seems to be very widespread. If any of you are techs or work for GM dealerships have you ever seen these being replaced under warranty or as part of the above special policies?

3) If an aftermarket cat a viable option? The direct fit part seems to be GM only and I'm concerned of longer term issues or not passing emissions if an OEM cat is not used
 

Gone_2022

TCG Elite Member
Sep 4, 2013
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My pre cat died on my Cruze at like 40k. I think that was more of a fluke though. That being said once the car goes out of the 8 year 80k warranty they won't help you on the cat replacement. GM won't even cover them after that if an engine failure took it out.

Look around and try to source a cat yourself. They are charging you a hefty mark up on it. Get the part number for the cat and search
 

muskie

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May 26, 2011
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Is it just me or is it absolutely mental that they are charging you that much to replace the cat?

Both dealers I called were within $25 of each other. Mitchell and Jennings.

I was floored when they called and said it was going to be $1200+

My pre cat died on my Cruze at like 40k. I think that was more of a fluke though. That being said once the car goes out of the 8 year 80k warranty they won't help you on the cat replacement. GM won't even cover them after that if an engine failure took it out.

Look around and try to source a cat yourself. They are charging you a hefty mark up on it. Get the part number for the cat and search

Are you able to lookup what labor time calls for to replace the cat on a 2011 Terrain?
 

Gone_2022

TCG Elite Member
Sep 4, 2013
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Both dealers I called were within $25 of each other. Mitchell and Jennings.



I was floored when they called and said it was going to be $1200+







Are you able to lookup what labor time calls for to replace the cat on a 2011 Terrain?




Customer pay time is 1.0 hours for the right side, 1.2 hours for the left side cat.

The rear cat is .8 hours.

Most of the cost is going to be the price of the cat which retails for almost 800 dollars
 

Gone_2022

TCG Elite Member
Sep 4, 2013
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Diag was covered already. Paid that.

What part number are you seeing? I found one in GM parts direct for like $500. Don't know if it is correct

Thanks for getting labor time.


I am not sure which side is bank 1 or bank 2 but

For right side part number is 25800997 - dealer list price is around $800

Left side part number 25800952 list is around $600

You can normally get both of the above cheaper through parts direct like you said or another route as dealers mark up the prices to the above mentioned to make a profit
 

Eagle

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Mar 1, 2008
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2011 Terrain SLE2 - 102,XXX miles

My questions to TCG

1) 102,XXX miles seems very premature for a cat failure. Is this normal? In my opinion it has to be from the oil consumption issue.

2) This seems to be very widespread. If any of you are techs or work for GM dealerships have you ever seen these being replaced under warranty or as part of the above special policies?

3) If an aftermarket cat a viable option? The direct fit part seems to be GM only and I'm concerned of longer term issues or not passing emissions if an OEM cat is not used

1. Agreed, most likely very much due to the oil consumption issue
2. If its past warranty by 22,000mi - you're going to have a hard time getting GM to do much about it
3. Hell yes its an option and no it shouldn't prevent you from passing emissions by using one.

My $.03
 

Gone_2022

TCG Elite Member
Sep 4, 2013
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I probably should have been clear. I have the 2.4. Believe me I regret this decision.


Ah in that case the front converter is 1.8 hours to replace rear is still .5 hours

Front converter part number is 22741673 and price is nearly $1000 dollars list at dealer

Rear converter is 20910568 and price is $600 list

I assume it's your front converter based on price.
 

muskie

TCG Elite Member
May 26, 2011
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Ah in that case the front converter is 1.8 hours to replace rear is still .5 hours

Front converter part number is 22741673 and price is nearly $1000 dollars list at dealer

Rear converter is 20910568 and price is $600 list

I assume it's your front converter based on price.

Thanks for all the info and help.

Definitely a pricey part, going to shop around.
 

Turbocharged400sbc

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Jun 16, 2007
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welcome to modern cars, yet another reason i wont own anything new...
your upstream cats are typically integrated into the manifold so they heat up and light off as fast as possible, you cant readily replace em with a cheap cat, not without extra labor of cutting/install/tack welding, removal, welding, reinstall.

one thing to note, the integrated cats tend to be the 3 way (Nox/HC/CO) while the downstream is usually just an oxidizing catalyst (2 way HC/CO)

your probably best to just toss a std cheapo cat in the downstream spot, keep in mind it'll be dead by the next test cycle (the cheapy's dont last long...they tend to lack the paladium/rhodium/platinum concentration of the OEM's

my gramps old oil burner 84 chrysler T&C (3.0 mitsu) passed every year in cali...with a cheapo....he'd bolt it on, test, remove, put on shelf for next year while the "test pipe" was installed (he had welded the pipe through the inside of a gutted cat shell for roadside visuals)

you could do the same thing

keep in mind that while oil consumption kills cats, non highway miles/<1 hr trips can kill em too...as the engine rings arent sealing as well as they could lending blowby oil to the mix....also without "hot" enough driving...the cat is dying as the outer "cooler" cells accumulate carbon/block off....and then starts inward...till its plugged/lost power/etc

it is however fairly baffling how the OEM's use baffles to remove oil from the PCv vapor...but never a cyclonic separator to take out even more suspended droplet/mist before burning it.
 

Nate

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I've done more Pistons, timing chains, balance chains, high pressure fuel pumps on these then I care to remember. However not many converter failures. The cost of the converter sucks. Plain and simple. The best you can do is call and bitch. Perhaps you can get the part for free and only have to pay labor/tax.

Aftermarket is fine. Just get one with a lifetime warranty
 

muskie

TCG Elite Member
May 26, 2011
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I've done more Pistons, timing chains, balance chains, high pressure fuel pumps on these then I care to remember. However not many converter failures. The cost of the converter sucks. Plain and simple. The best you can do is call and bitch. Perhaps you can get the part for free and only have to pay labor/tax.

Aftermarket is fine. Just get one with a lifetime warranty

You aren't the first tech I've hear that from.

I really do like the car despite the fact I've been getting nickle and dimed like mad over the last 8 months with it.

Thanks for all the input everyone. I've found a hookup through CarQuest and found a much more reasonable price on a new direct fit converter so I'll more than likely be going the route.
 
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