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Posted: 4/16/2017 10:23:01 PM EDT
I hope site is OK with this, but I will send a free PMag to anyone who can help up figure out the issue below.  

A friend of mine has what seems to be a possessed '11 GMC Acadia with 98k, and its become a bit of a nightmare for her.  I don't think its ever been right, even off the lot, and has finally died at the GM dealership.  Its always been a bit of an oil burner, and according to her, she has to change the oil every 3k miles (otherwise level gets too low).  She's never been able go by the oil change light, even when practically new.  

About 6 months ago, the vehicle started pouring white smoke, and was diagnosed as a stuck injector (which was replaced).  The rest of the fuel system was cleaned, and had no more issues until about 2 months ago.  This time, there was a power loss while driving, and was described as "not being able to get out of 1st gear".  It would idle OK, but had no power on driving.  It was taken back to the shop, who got inconsistent fuel pressure readings and replaced the low pressure fuel pump.  Once again, vehicle would crank and idle, but died going down the road.  Went through it, and found that 2 of the 3 catalytic converters were practically melted to the frame and destroyed.  Replaced the two converters with aftermarket versions, and vehicle cranked and idled fine.....but once again died going down the road.  

This time, they gave up on the independent shop and had it towed to the dealer.  Dealer claimed that the aftermarket converters were the problem, and that factory GM converters would fix the issue.  Dealership agreed that if the new GM converters didn't fix the issue, they wouldn't be charged (and would be given back the old converters to return).  Well, they swapped in the new converters, and called and said everything was fixed.  Owner insisted they drive it first, and of course, it died going down the road.  Got it back to the shop, and now they are claiming it will require an engine replacement.  Supposedly, they ran a camera in through the intake, and can see debris from the damaged converters...and has wrecked the engine.  They also claim that the aftermarket converters have already been trashed.  

At this point, she has no idea how to proceed.  It still sounds like a stuck/leaky injector may be an underlying issue, but I am absolutely unfamiliar with these vehicles.  As far as she knows, the only code its ever thrown was "back pressure in the converters".  

Any suggestions?
Link Posted: 4/16/2017 10:28:41 PM EDT
[#1]
Which engine? Need to know how many cylinders first.
Link Posted: 4/16/2017 10:32:29 PM EDT
[#2]
If there was enough reversion to get pieces of the convertors back into the engine, then she had much more serious problems than the convertors.  I call BS on that diagnosis.  A simple compression and/or leakdown check should tell them a lot but it doesn't sound like they've done that.

Oh, and pics of friend?  
Link Posted: 4/16/2017 10:44:36 PM EDT
[#3]
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Quoted:
Which engine? Need to know how many cylinders first.
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Best I can tell, the '11 was only offered with the 3.6 L LLT V6.
Link Posted: 4/16/2017 11:35:11 PM EDT
[#4]
The wife had an Acadia with heavy oil usage.  There is a know problem with the pressed-in tube going into the head where the spark plugs go.  The pressed-in tubes cracks/breaks and allows oil into the combustion chamber and foul out the plugs.  At 99,5XX miles her Acadia started to smoke and had a rough idle.  I pulled the plugs and found one oil fouled (Actually the first one I pulled).  We took it in and they discovered a tube on the other head was leaking also.  They ended up replacing both heads and timing chain (which had been noisy since we bought it).  We traded it 6 months later.
Link Posted: 4/16/2017 11:40:19 PM EDT
[#5]
BS on the converters causing engine failure IMO.

That said, those things are giant pieces of shit.
Link Posted: 4/16/2017 11:45:45 PM EDT
[#6]
BS on the converters causing engine failure IMO.
View Quote


Sounded odd to me.
Link Posted: 4/16/2017 11:47:11 PM EDT
[#7]
leaking injector allowed too much fuel out thus loading the converters up causing them melt and come apart. The engine sucked pieces into the engine and destroyed it.

The converter is really close to the exhaust manifold is the reason why it sucks it back into the engine link

Link Posted: 4/16/2017 11:49:38 PM EDT
[#8]
Link Posted: 4/16/2017 11:52:14 PM EDT
[#9]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
leaking injector allowed too much fuel out thus loading the converters up causing them melt and come apart. The engine sucked pieces into the engine and destroyed it.
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I respectfully disagree.  While there's some minor amount of reversion taking place in all internal combustion engines, it's minimal on one with a stock camshaft.  Engines typically don't "suck" stuff back up the exhaust pipe when the exhaust valve is open.
Link Posted: 4/16/2017 11:53:22 PM EDT
[#10]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
leaking injector allowed too much fuel out thus loading the converters up causing them melt and come apart. The engine sucked pieces into the engine and destroyed it.
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No mechanic here, that does sound like a possibility now that jeep laid it out like that. How can that thing run with enough back pressure to move those pieces all of the way back to the head? Craziness to think about.
Link Posted: 4/16/2017 11:55:23 PM EDT
[#11]
I would probably cut my losses, I'm scared to even ask how much she has put into that thing just in maintenance/repairs at this point, probably could have damn near bought a replacement vehicle. A used one is maybe worth $10k, what's a new engine from the dealer for that thing $5-6k? 
Link Posted: 4/16/2017 11:57:32 PM EDT
[#12]
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Quoted:
No mechanic here, that does sound like a possibility now that jeep laid it out like that. How can that thing run with enough back pressure to move those pieces all of the way back to the head? Craziness to think about.
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
leaking injector allowed too much fuel out thus loading the converters up causing them melt and come apart. The engine sucked pieces into the engine and destroyed it.
No mechanic here, that does sound like a possibility now that jeep laid it out like that. How can that thing run with enough back pressure to move those pieces all of the way back to the head? Craziness to think about.
converters mounted extremely close to the cylinder head, and before you guys start bashing GM for the design many brands are doing the same thing and seeing the same thing.
Link Posted: 4/17/2017 12:00:27 AM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
converters mounted extremely close to the cylinder head, and before you guys start bashing GM for the design many brands are doing the same thing and seeing the same thing.
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Quoted:
Quoted:
Quoted:
leaking injector allowed too much fuel out thus loading the converters up causing them melt and come apart. The engine sucked pieces into the engine and destroyed it.
No mechanic here, that does sound like a possibility now that jeep laid it out like that. How can that thing run with enough back pressure to move those pieces all of the way back to the head? Craziness to think about.
converters mounted extremely close to the cylinder head, and before you guys start bashing GM for the design many brands are doing the same thing and seeing the same thing.
That's extremely common these days due to federal emissions requirements.  Thanks Obama!  

Seriously though, the feds require the catalyst to begin doing it's job within a certain time from engine startup, and placing them closer to the manifolds allows them to get up to operating temperature quicker.
Link Posted: 4/17/2017 12:01:29 AM EDT
[#14]
Discussion ForumsJump to Quoted PostQuote History
Quoted:



converters mounted extremely close to the cylinder head, and before you guys start bashing GM for the design many brands are doing the same thing and seeing the same thing.
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Maybe so, but you see many more equinox/acadia lemons per capita around here.
Link Posted: 4/17/2017 12:02:33 AM EDT
[#15]
Blown up engines don't usually idle fine. Cat chunks in the muffler? Clogged fuel filter (yes, it has one)? Clogged air filter?
Link Posted: 4/17/2017 12:03:09 AM EDT
[#16]
How much of the maintenance was done at a GM dealer ?

Acadia's were known for problems especially around the 2010-2012 models and there were a TON of service bulletins on them to fix issues for free.
Just as long as it was dealer serviced.

Taking it to an indy and having aftermarket cats put on it was a big no-no and your lady friend will be basically told to pound sand by GM.

It was out of power train warranty last year, it's time or mileage whatever come first.
The emissions warranty would have still been in effect IIRC had she not had the cats changed out at an indy shop, if the GM shop says the engine is toast due to the cats and it had GM cats on it the engine would have been replaced by GM.

She's on the hook for the repair or she walks, hopefully the rig is paid off
Link Posted: 4/17/2017 12:06:52 AM EDT
[#17]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
converters mounted extremely close to the cylinder head, and before you guys start bashing GM for the design many brands are doing the same thing and seeing the same thing.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
leaking injector allowed too much fuel out thus loading the converters up causing them melt and come apart. The engine sucked pieces into the engine and destroyed it.
No mechanic here, that does sound like a possibility now that jeep laid it out like that. How can that thing run with enough back pressure to move those pieces all of the way back to the head? Craziness to think about.
converters mounted extremely close to the cylinder head, and before you guys start bashing GM for the design many brands are doing the same thing and seeing the same thing.
I have seen it happen personally on a newer Ford. When the cats start to come apart and clog, the engine may ingest the particles when the vehicle begins to backfire.
Link Posted: 4/17/2017 12:07:15 AM EDT
[#18]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I would probably cut my losses, I'm scared to even ask how much she has put into that thing just in maintenance/repairs at this point, probably could have damn near bought a replacement vehicle. A used one is maybe worth $10k, what's a new engine from the dealer for that thing $5-6k? 
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Last one we did was over $11K.
Link Posted: 4/17/2017 12:12:52 AM EDT
[#19]
The problem is those things are fucking garbage. I'll PM you my address.
Link Posted: 4/17/2017 12:26:51 AM EDT
[#20]
The emissions warranty would have still been in effect IIRC had she not had the cats changed out at an indy shop,
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I think cats are 8 yrs/80k miles, so she would have likely been out of warranty.
Link Posted: 4/17/2017 12:33:21 AM EDT
[#21]
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Quoted:


I think cats are 8 yrs/80k miles, so she would have likely been out of warranty.
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Correct.

It's 8yrs/130,000Km so I missed the conversion.
Link Posted: 4/17/2017 12:46:31 AM EDT
[#22]
I know I'm old school but I'm trying to wrap my head around even cats being closer to the engine, enough back pressure to suck garbage in.

I get the stuck injector killed the stock cats, but I would want a compression test done, and condition of the plugs. I wonder if it was running fat enough to foul them out, and the whole mess that brings.

The oil consumption is concerning, for sure. There was a post that suggested a plausible explanation for that.
Link Posted: 4/17/2017 2:21:18 AM EDT
[#23]
I get the stuck injector killed the stock cats
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Whats interesting, the dealership is claiming that the replacement cats have already been ruined....and the vehicle has probably seen less than 5-10 miles since they were installed (probably less than that).
Link Posted: 4/17/2017 2:37:29 AM EDT
[#24]
They are assuming the cats are bad.  ask for pics if they physically inspected them.

As noted, those vehicles had many many engine issues.  stuck injectors likely caused most of this.  The 3.6's also had a problem with massive carbon buildup on the intake valves that can cause various issues.
Link Posted: 4/17/2017 4:47:32 AM EDT
[#25]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
BS on the converters causing engine failure IMO.

That said, those things are giant pieces of shit.
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Sorry, but you are wrong, I have quite a few 3.6 GM engines fail due to cats coming apart. The cats on the 3.6 bolt right to the exhaust manifold or on some 3.6 engines are the exhaust manifolds.

The original dieing could be from electrical connector issues. I have seen bad coils grounds cause misfires bad enough to destroy the cats.

Then again I work on GM cars every day.  Best thing you can do is stay out of most independent shops.
Link Posted: 4/17/2017 5:17:45 AM EDT
[#26]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


That's extremely common these days due to federal emissions requirements.  Thanks Obama!  

Seriously though, the feds require the catalyst to begin doing it's job within a certain time from engine startup, and placing them closer to the manifolds allows them to get up to operating temperature quicker.
View Quote
So does overfueling them.
Link Posted: 4/17/2017 1:46:16 PM EDT
[#27]
What the dealership is saying sounds plausible. I know last generation NISSAN Altima's had the same problem. Time to junkyard the thing and move on to something else.
Link Posted: 4/17/2017 5:20:07 PM EDT
[#28]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
That's extremely common these days due to federal emissions requirements.  Thanks Obama!  

Seriously though, the feds require the catalyst to begin doing it's job within a certain time from engine startup, and placing them closer to the manifolds allows them to get up to operating temperature quicker.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Quoted:
leaking injector allowed too much fuel out thus loading the converters up causing them melt and come apart. The engine sucked pieces into the engine and destroyed it.
No mechanic here, that does sound like a possibility now that jeep laid it out like that. How can that thing run with enough back pressure to move those pieces all of the way back to the head? Craziness to think about.
converters mounted extremely close to the cylinder head, and before you guys start bashing GM for the design many brands are doing the same thing and seeing the same thing.
That's extremely common these days due to federal emissions requirements.  Thanks Obama!  

Seriously though, the feds require the catalyst to begin doing it's job within a certain time from engine startup, and placing them closer to the manifolds allows them to get up to operating temperature quicker.
That cat location had nothing to do with NObama, the GM R/V suv was designed in '04-'05 and first into production in '06. Big cats near the manifolds clean up exhaust much better than down stream.

3,000 miles being down a quart is pretty normal for oil consumption. The 'oil life monitor' on that year Acadia was 10,000 miles between changes, I recommend 5,000 mile oil changes if running oil like Mobil One and it gets driven 20-30 miles at a time.
Link Posted: 4/17/2017 8:37:45 PM EDT
[#29]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
That cat location had nothing to do with NObama, the GM R/V suv was designed in '04-'05 and first into production in '06. Big cats near the manifolds clean up exhaust much better than down stream.

3,000 miles being down a quart is pretty normal for oil consumption. The 'oil life monitor' on that year Acadia was 10,000 miles between changes, I recommend 5,000 mile oil changes if running oil like Mobil One and it gets driven 20-30 miles at a time.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Quoted:
Quoted:
leaking injector allowed too much fuel out thus loading the converters up causing them melt and come apart. The engine sucked pieces into the engine and destroyed it.
No mechanic here, that does sound like a possibility now that jeep laid it out like that. How can that thing run with enough back pressure to move those pieces all of the way back to the head? Craziness to think about.
converters mounted extremely close to the cylinder head, and before you guys start bashing GM for the design many brands are doing the same thing and seeing the same thing.
That's extremely common these days due to federal emissions requirements.  Thanks Obama!  

Seriously though, the feds require the catalyst to begin doing it's job within a certain time from engine startup, and placing them closer to the manifolds allows them to get up to operating temperature quicker.
That cat location had nothing to do with NObama, the GM R/V suv was designed in '04-'05 and first into production in '06. Big cats near the manifolds clean up exhaust much better than down stream.

3,000 miles being down a quart is pretty normal for oil consumption. The 'oil life monitor' on that year Acadia was 10,000 miles between changes, I recommend 5,000 mile oil changes if running oil like Mobil One and it gets driven 20-30 miles at a time.
Hence the smiley face.  Looks like you need to learn how to repair sarcasm meters like you do GM cars, cause yours is broken...  
Link Posted: 4/21/2017 10:11:21 PM EDT
[#30]
UPDATE

Well, after some back and forth with the dealership, she is getting a new engine.  I have no idea what GM told her, but they will be replacing the motor....to the tune of $7100.  She'd found a used motor with 41k miles for $3500, but decided to stick with the dealership.  I encouraged her to get it checked out by someone else, but at this point they are ready to give up.  She's determined to not have a car payment, and even though she's putting $7100 in a vehicle that will only be worth $9k, at least it will be done.  

Not quite what I would have done, but she's stuck between a rock and a hard place.
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