2012 GMC Terrain has oil consumption issue GM rebuilt engine with 112000 km one year later I just took it in and it needs a catalytic converter my question is would the oil consumption issue lead to the catalytic converter failing early (inefichent code) is what came up
If partially burned oil goes through the catalytic converter with the exhaust, yes, it could foul the converter.
Thanks that’s what I figured great now I get to go toe to toe with GM again the dealer was quick to jump in and pay for 1/3 rd because they know the history of the car it’s also gone through 5-6 cam actuators in the last 3 years one lasted less than a day
Yup.
The cat converter has a core of a honeycombed ceramic coated with platinum-palladium. When the nitrous oxides (NOx molecules) in the exhaust come in contact with the hot platinum-palladium, the atoms separate and the oxygen atoms become free to bond with carbon monoxide molecules creating carbon dioxide (CO2), and allowing (in the hot converter) unburned hydrocarbons to split and bond to the oxygen atoms, forming ideally CO2. That last part is often called the “second burn”.
The trick is that the exhaust stream has to come in direct contact with the platinum-palladium. Burning oil slowly coats the cat converter core with carbon. That insulates the cat converter core against the exhaust stream and the chemistry can’t happen. As the core gets coated, the converter gets less efficient.
Best of luck going after GMC for coverage.
excessive oil consumption can certainly hasten a catalytic converter’s demise
But it’s by far not the only thing that can cause a catalyst low efficiency code. I assume you have either p0420 and/or p0430
I’m mentioning this because we have lots of vehicles in our fleet which consume oil, yet their catalytic converters are okay. And I would know, because I’m the guy doing the smogs.
Exactly how much oil is the engine consuming?
How many quarts per 1000 miles?
That information would help, because then we’d know how serious it is
I’d guess that the 112,000 kilometers of oil burning to the extent that GM was willing to rebuild the engine were a bigger factor that the current consumption, whatever that is.
Best we could figure was 2-3 quarts every 1500 miles the dealer paid for over half the repair cost complete engine rebuild right off the bat as the car had never missed a scedualed service and as soon as GM added the 2012 Terrain to the recall list for oil consumption a month later GM cut us a check three days after notifing us of the recal since the rebuild last year it’s not burning a drop of oil we have it serviced every 5000 km regardless of the oil life monitor reading now imo the first problem may have contributed to the cat failing actually GM just ate half the cost of the replacement (not complaining ) as they put a portion through warranty as the cat had just expired
Thank you for that information
That’s extremely high oil consumption, in my opinion, and was almost certainly a factor in the demise of your catalytic converter, assuming it truly is bad
As I said before, you should get definitive diagnosis
I’d hate for you to make assumptions, replace the cat, and maybe STILL get that same code afterwards
Ya the cat was replaced today I’m driving from Canada to Florida tomorrow they did run a full diagnosis on the car for us as we are traveling so should be a good test and I’ll do another oil change when we get back always noticed the excessive oil loss after a long trip so should be a good test
Happy trails.
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I really hope that does not mean you don’t check oil level until you complete trip. You should check every morning on this trip just to be safe.
Check the oil level on the dipstick now and a few times along the way. Enjoy the warmer temperatures in Florida 
I’m curious about the oil change regimen as that can cause oil consumption issues if it’s too lengthy.
Per your prior comment, I read it as returning from a long trip and noticing a severe low oil level beause it was never checked during the trip. That can also cause oil consumption problems.
Per your comment about multiple cam actuator failures I can surmise that is due to not changing the oil often enough and/or running the engine oil chronically low.
I hadn’t caught the details earlier, but I agree with OK4450’s impressions… and questions.
So far all is good as for the oil change before the engine rebuild maybe the most ever went over 5000 miles was once due to unplanned trip and oil life monitor was still indicating 20% oil life remaining (5800 miles) when I got to my destination as far as the cam actuator one failed at 3500 miles after oil change and the second failed 1400 miles after being replaced car has had every scheduled service as per the GM recommendation I even did a 2nd trans flush prior to this trip at 132,000 think GM recommends every 72,000 miles we do do a lot of long road trips and usually have the car serviced prior to each long trip regardless GM has a recall service bulletin on the 2.4 L engines from like 2008-09 until 2015 if I remember right built with low friction rings I believe the actuator failures were cause from high oil consumption on these longer trips but the dealers never caught the low oil during service and I never noticed any major oil consumption during day to day driving
So can I assume from this statement that you weren’t monitoring your own oil? You were abdicating your responsibility to do so?
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To be totally honest never had a problem until we lost the 2nd cam actuator car never used any oil and because the oil was changed out every 3500 -4000 miles never noticed any loss he’ll i have a dodge dakota with 400,000 miles Thad don’t use a drop yes I always checked oil before any long trip the first time we had a issue was on a trip back from Florida to Canada and checked oil when check engine light came on and oil was down 2 quarts and before GM could finish a oil consumption test the decided to rebuild due to our service history and the dealer knowing of this problem with this engine
It is possible that cam actuator related fault codes were set after the oil level became critically low causing low oil pressure.
While refilling the engine with oil may have corrected the problem some technicians refuse to work for free, manufactures warranty won’t pay the tech to add oil to the engine and 30 to 45 minutes may have been wasted inspecting the vehicle so they replace the cam actuators.
You must have great confidence in your vehicle if you think you can drive from Florida to Canada without checking the engine oil level during the trip.
Running an engine down 1 quart of motor oil can damage it. Down 2 quarts is even worse. That’s 20 to 40% of the motor oil in the engine assuming a 5 quart motor.
The reason why is that oil also cools the engine. When the oil level drops a quart or two the temperature of the remaining oil goes way up. That in turn leads to oil coking in various areas and can also cause the oil control rings (or wiper rings) to seize in the piston lands. The latter leads to oil consumption as the wiper rings are unable to “breathe” so to speak and wipe the cylinder walls on the piston downstrokes.
It’s not just a Terrain that will suffer this way. It’s any internal combustion engine.
You didn’t answer my question. You danced around it.
So, you weren’t regularly monitoring your oil? You were only checking it “before any long trip”? And you drive from Florida to Canada and didn’t check it until the oil light came on?