Sugar Bears 2015 GMC Terrain SLE-2 2.4 AWD

diyer2 · January 9, 2022

Seems like this motor design is a poor one. My son has the same motor as I have mentioned. It's his daughters car and she lives with her mom. So the granddaughter swings by my sons house so he can check the oil etc. He replaced the head, remember? Since he replaced the head he has done 1 oil change, about 3k I think. He doesn't use mileage, he uses the computer. The oil consumption went down a little just before the first oil change.

There are design problems in a lot of products, comes with a new design or just a poor design from the start. A case in point. My brother in law, a very smart and handy fella was making money on a design flaw in a brand of big screen TV. This was a Plasma TV highly rated for it's picture quality. This was a few years back. There were a lot of these non-working out of warranty TV's for sale on craigslist.

He bought one not working, figured out the problem. He could fix it for a few dollars in parts, I think it was a resistor that failed and a few hours of his time. He was repairing them and reselling them. The manufacturer was charging a high price for a Printed Circuit Board replacement, so people just sold them cheap.

GM's lifter problem also comes to mind.

Edited January 9, 2022 by diyer2

customboss · January 9, 2022

Grumpy's analysis result showed 6.5% fuel in oil, a healthy perfectly operating engine should never be higher than 0.5% fuel in oil. Especially one that is tenderly loved and maintained like Grumpy does.

DI engines with issues or wear may show 1% fuel in oil via gas chromatography.

This is why employing labs that don't use a properly calibrated fuels reading will misguide the user. Flash point variation on a curve for new engines won't give an accurate reading.

Feeling a miss is not gonna happen anymore like 40 years ago unless a coil/s totally fail or severe mechanical issue.

The ignition systems firing so well and driveline mounting and insulation absorb NVH by design mask all that feeling of a problem in early stages at least.

Getting a good oil analysis showed problems in Sugar Bear and Pepper both have had issues masked by Grumpy being so good at maintenance but not changing out or correcting the causal of the main issues.

Combustion dynamic is THE critical issue to maintain and OEM recommendations and geared for emissions reduction and quietly encouraging you to trade within a certain time.

Optimizing a modern IC engine means assumptions must be challenged for ideal operation.

The whole point on this site is to optimize our trucks so this is just an underused tool to do just that regardless of opinion.

Focus on nitration and fuels dilution moderating lower and your wear control will follow. Masking issues by exceptional lubricants, ECM tuning, frequent oil changes WILL NOT correct basic IC engine dynamics just make you feel good.

DIYER2 is right, the designs can be defective or at least unable to overcome lubricants and fuels technologies deficiencies over time and then your maintenance regime can correct or lower risk of damage, failure, make it more dependable. Keep it internally clean, burning and firing best we can and your truck and you will be happier from my testing experience over the years.

KARNUT · January 9, 2022

18 minutes ago, customboss said:

Grumpy's analysis result showed 6.5% fuel in oil, a healthy perfectly operating engine should never be higher than 0.5% fuel in oil. Especially one that is tenderly loved and maintained like Grumpy does.

DI engines with issues or wear may show 1% fuel in oil via gas chromatography.

This is why employing labs that don't use a properly calibrated fuels reading will misguide the user. Flash point variation on a curve for new engines won't give an accurate reading.

Feeling a miss is not gonna happen anymore like 40 years ago unless a coil/s totally fail or severe mechanical issue.

The ignition systems firing so well and driveline mounting and insulation absorb NVH by design mask all that feeling of a problem in early stages at least.

Getting a good oil analysis showed problems in Sugar Bear and Pepper both have had issues masked by Grumpy being so good at maintenance but not changing out or correcting the causal of the main issues.

Combustion dynamic is THE critical issue to maintain and OEM recommendations and geared for emissions reduction and quietly encouraging you to trade within a certain time.

Optimizing a modern IC engine means assumptions must be challenged for ideal operation.

The whole point on this site is to optimize our trucks so this is just an underused tool to do just that regardless of opinion.

Focus on nitration and fuels dilution moderating lower and your wear control will follow. Masking issues by exceptional lubricants, ECM tuning, frequent oil changes WILL NOT correct basic IC engine dynamics just make you feel good.

DIYER2 is right, the designs can be defective or at least unable to overcome lubricants and fuels technologies deficiencies over time and then your maintenance regime can correct or lower risk of damage, failure, make it more dependable. Keep it internally clean, burning and firing best we can and your truck and you will be happier from my testing experience over the years.

How much of a miss before the check engine light comes on? As sensitive as pollution devices are along with regulation any miss would be a problem? I would think that much fuel would be an injection problem, more than a miss fire. Interesting.

customboss · January 9, 2022

21 minutes ago, KARNUT said:

How much of a miss before the check engine light comes on? As sensitive as pollution devices are along with regulation any miss would be a problem? I would think that much fuel would be an injection problem, more than a miss fire. Interesting.

Karnut thats a great WISE question and the answer from a retired engineer from a OEM ( who worked directly with MIL coders programming)...... Not until it exceeds the exhaust test bag emissions limits.

The ONLY reason for MIL system is tail pipe and vented emissions from exceeding EPA standards for engineering year. PERIOD. Everything else is marketing and keeping warranty to NIL.

Why a dealer will drive/test/inspect a unit with obvious issues but no code and send you home with a reset on system.

customboss · January 9, 2022

If your after-treatment and vent containment is hiding the problem its not a problem to OEM's and Gov.

Grumpy Bear · January 9, 2022

I expect this, in the end, to not be a single issue but the sum of several. Under guidance my goal is to sort each possible solutions contribution to that sum.

Grumpy Bear · January 15, 2022

1/15/2022 Update

Collecting parts, supplies and waiting on this or that....

1.) The ignition parts are in house. Have been almost two weeks now but getting a window of time to do the job has been something else. Weather. Battery in the backup car. Wife's need for use for work.... Hoping mid next week for weather/wife break to get this done. I'd like to have this part finished before the next oil change.

2.) Injectors are still in a holding pattern as my mechanic and his 5 year old son is battling both Covid and moving his shop.

3.) Took delivery on case of:

Things will fall pretty much in this order. Repair, test, rinse and repeat until we have a good result or a conformation she's past resurrection.

On 1/9/2022 at 10:49 AM, customboss said:

Masking issues by exceptional lubricants, ECM tuning, frequent oil changes WILL NOT correct basic IC engine dynamics just make you feel good.

A note on this comment above. It will do more than make you feel good. It will keep you motor alive buying time to make those corrections. Masking? Yes! Band-Aid's? Yes again! But not without usefulness any more than a bilge pump is useless. Keeps the boat afloat

A faulty ignition is a possible source of the excess fuel. And so is a bad injector. But so is a power cylinder that is not sealing and if this third situation is the case then there will be no improving the breathing (vent/pcv system) to be realized.

The assumption at this point is the fuel dilution breaking the viscosity is causing both the majority of the oil consumption and the excess vapor traffic. If it has lost containment due to viscosity break then one of the first two items should slow it or stop it. If both fail varnished rings is the next most likely issue. Purpose of the Restore. If after that it refuses to abate..... stick a fork in it OR continue till the cows come home with crappy oil and short OCI's.

Full disclosure here. I have two of these 2.4 pigs and the second only has 14K on the clock. Experience with this current situation will determine much about the future maintenance of the second. So the Terrain is a Guinea Pig for the Buick. Is what it is.

Edited January 15, 2022 by Grumpy Bear

Grumpy Bear · January 20, 2022

1/19/2022

Deegan's has reopened and we have an appointment for 1/24/2022 for the ignition work at which time we will also reset the ECU. I'll give a few hundred miles to settle in then change oil and we will see what that bought us? (UAO). Then move to step 2.

I've decided that the second step will be not only injectors but cleaning the entire PCV system as well instead of pulling the intake twice. Too much $$$$.

Jason is well. Very tired but testing negative. His son is recovering but his 39 year old cousin passed. (COVID-19).

Grumpy Bear · January 24, 2022

156,640 Mile Services

1/24/2022

Replaced coils, boots and plugs. Denso's best coil line and NGK Ruthenium plugs gapped .040 (1 mm) LTR5AHX

Iridium plugs that were removed looked okay and the coils metered okay. Boot pliable and carbon free. That said what a coil does on the bench means little under working pressures. Did not scope it before replacement. #1 plug had a bit of scaling but nothing that raised an eyebrow. No oil and dry as a bone. I get that same type of scaling in the HD around 5K miles when it starts missing. This set had about 56K on them.

Reset ECU. Fuel trims reset.

It does idle smoother so something and not nothing.

1K miles on this OCI and still full. No fluid in the fresh side PCV air supply pipe or trap. Give the ECU a few hundred to relearn then change oil and see what the next UOA shows.

I've gotten into the practice of running in M5 when under 55 mph to keep manifold vacuum higher and it seems to improved the venting accordingly.

Edited January 24, 2022 by Grumpy Bear

Grumpy Bear · January 25, 2022

Valve cover baffle PCV baffle is riveted in.

Rivets drilled out

Fresh air side baffle exposed

Not really cleanable.

Edited January 25, 2022 by Grumpy Bear

customboss · January 25, 2022

6 minutes ago, Grumpy Bear said:

http://www.kappaperformance.com/forum/index.php?topic=11671.0

Only photo's I've found for the baffling of the valve cover.

http://i.imgur.com/bGt69O9.jpg

http://i.imgur.com/GmhRyfe.jpg

http://i.imgur.com/EinRYdi.jpg

Do you think that the vent baffling is damaged or restricted in some way? If restricted by shellac or sludgy deposits IF the blow-by and vent gases have the Cummins RESTORE in the flow that chemistry will clean it up. If its damaged mechanically then nothing but repair will correct.

Thats quite an extensive vent system.

Grumpy Bear · January 25, 2022

4 minutes ago, customboss said:

Do you think that the vent baffling is damaged or restricted in some way? If restricted by shellac or sludgy deposits IF the blow-by and vent gases have the Cummins RESTORE in the flow that chemistry will clean it up. If its damaged mechanically then nothing but repair will correct.

Thats quite an extensive vent system.

I reloaded that post to rid it of the links.

Damaged? No I don't think so. Dirty? Yes. Plugged? No. Short ramble.

Between very long legged gearing and cam phasing, both to reduce pumping losses the manifold vacuum runs near atmospheric and as it is orificed and not valved flow goes both ways driving moisture into the fresh air side. Carries moisture into the air box trap where it freezes and the result is blown seals. Been there, done this. Cold weather is not her friend.

Running in M5 greatly increased the manifold vacuum and the moisture is greatly reduced. Hum....

I've been following a fellow who has installed a proper PCV which is really quite simple, for about a year. He routed it via a catch can. Which may make sense IF the baffling does not support the valve. I wanted to know exactly what was under there so I went fishing and caught the days limit. Eliminating backflow to prevent the freezing and increasing volume is the goal.

customboss · January 25, 2022

2 minutes ago, Grumpy Bear said:

I reloaded that post to rid it of the links.

Damaged? No I don't think so. Dirty? Yes. Plugged? No. Short ramble.

Between very long legged gearing and cam phasing, both to reduce pumping losses the manifold vacuum runs near atmospheric and as it is orificed and not valved flow goes both ways driving moisture into the fresh air side. Carries moisture into the air box trap where it freezes and the result is blown seals. Been there, done this. Cold weather is not her friend.

Running in M5 greatly increased the manifold vacuum and the moisture is greatly reduced. Hum....

I've been following a fellow who has installed a proper PCV which is really quite simple, for about a year. He routed it via a catch can. Which may make sense IF the baffling does not support the valve. I wanted to know exactly what was under there so I went fishing and caught the days limit. Eliminating backflow to prevent the freezing and increasing volume is the goal.

Your improvement of combustion dynamic via plugs,boots,coils, even relays, will be interesting and germane to the issues you describe. THIS MAY be one case were the design demands an improved CCV regime. Be sure to watch the Aussie weirdo's video.....LOL

Grumpy Bear · January 25, 2022

1 minute ago, customboss said:

Your improvement of combustion dynamic via plugs,boots,coils, even relays, will be interesting and germane to the issues you describe. THIS MAY be one case were the design demands an improved CCV regime. Be sure to watch the Aussie weirdo's video.....LOL

You are a funny funny guy.

:crackup:

Adding this for my record.

The thing with this motor is no one seems to know if the dog is wagging the tail or his tail is wagging the dog. Could be these motors crap out like flipping a switch at 75K miles due to the stated Poor oil ring design. Maybe but it begs the ask: SO why run perfect for the first 75K. Okay something is building up. But what and where? Are rings collapsing because of poor oil drain rates or because it gets flooded with materials that should have been more fully vented?

So far we have a TSB for 'clearing the orifice. $500 a pop and we still have the problem. Replace the rings, $3K a pop and we still have the problem. Much shorter OCI's when GM has a memo on and did in fact reprogram the earlier motors OLM's to tap out earlier. And we still have the problem. I want the problem GONE

customboss · January 25, 2022

6.5% fuels in oil would not assist crankcase venting optimization thats for sure.

There's the beginning of your solution.

If you have high fuels dilution over 150,000 miles of use, especially undetected @ 6.5% or more thats a major contributor if not cause of the issues you have shared.