6.2L active fuel management and lifer/cam failures.

[ZooMad75]

Thanks for the info,it's funny the varying info you get. When my wife bought her acadia in 2017 they told me Dexos was a blend when I asked, so I just assumed it still was, but apparently they didn't know what they were talking about.

I do run a oil catch can in the PCV hose on mine because the DI motors don't ever get the fuel on the back of the intake valve, so I thought it might help prevent carbon buildup(I could see oil pudding in the intake behind the throttle body when I installed it at 1400 miles). I wouldn't bother if it was MPFI. Do you see any of that with the higher mileage motors or what's the latest verdict on the 2014 and later models? When I bought it 3 years ago it seemed it was too early to tell.

We haven't run into any with carbon buildup. So far. Really depends on how somebody takes care of it. The DI 3.6 we've seen carbon buildup on high mileage units, but those are usually the ones going 8-10k or better between services. Pull the cam covers on them and it's full blown sludge city. That crap coats the cam phaser solenoid valves and surprise, the cams don't advance or retard timing correctly. Check engine light on, runs like hammered dog crap since the cams won't go where they need to. All preventable. Change it often with the right sauce and they keep rolling without issue.

 

[tRustyK5]

It's funny, my oil life monitor always reads somewhere around 40% life when I get it changed. Not knowing better with my previous truck I followed the oil life monitor once and it went to 12,000 km. (7500 miles).

It seems 3000 miles for regular oil, and 5000 for synthetic is the correct range to prevent issues, not just with these DI engines, but with anything. I do remember those oil change commercials "You can pay me now, or pay me later..." lol

 

[cuervo]

I only have less than 30k on it. The only issue I have ever had with it that popped up recently is the torque converter shutter, I need to take it in to see if the warranty flush fixes it or if they will need to replace the torque converter, the powertrain is 5 year warranty. You have the 10L90, hopefully they finally fixed that issue, seems a little ridiculous to me. We have two 2016s and a 2018 8L90 between myself, father and brother in law, and all 3 of them have done it at some point. The dealer has said the latest fluid will fix it, we'll see, I need to schedule it.

This guy talks about the stutter and which fluid to use in the 6, 8, and 10 speeds. He also goes over the procedure for checking the fluid level in the GM transmissions that don't have dipsticks.

Video timeline is of the fluid types.

 

[K85 Octane]

So we need Zinc for flat tappet lifters
Fancy stuff for the new engines or they die quicker than the old engines
and
"Who-gives-a-damn" for that period in between, which provided engines that lasted well, actually they're are still going

 

[76zimmer]

Pretty elaborate procedure, I wonder how many actually follow that when checking. I’m sure the quick change oil shops do...
Also IME at the dealership, they use bulk oil for most cars, and I wonder if you get what you pay for with the special needs of different cars?

 

[ZooMad75]

Pretty elaborate procedure, I wonder how many actually follow that when checking. I’m sure the quick change oil shops do...
Also IME at the dealership, they use bulk oil for most cars, and I wonder if you get what you pay for with the special needs of different cars?

It's ridiculous. But unfortunately not uncommon. Check any Dodge or Ram product with the tranny's they use and you'll find only the dealer has a dipstick for them as a special tool. Not to come with the vehicle.

As far as the oil goes, the darn things are sensitive enough if we don't put the right stuff in them, they can set a code and turn on the check engine light before it leaves the lot. We had a Buick Regal the Ford dealer brought over to us just after an oil change they did. They used the Motorcraft Synthetic blend that wasn't Dexos rated. Instantly set cam phaser codes and rattled like mad. Got permission to dump the oil and put the right stuff in it and the rattle disappeared and cam phasers came back into play and started working correctly again. That was the car that proved it for me. Had I not see that thing before and after I would have called BS on oil being the cause. But we were all floored by it.

 

[76zimmer]

Good info to have!

 

[btblazer]

I have a 2008 GMC denali with the 6.2l and it has all that active fuel management and variable valve adjustment stuff. I currently have 260,000 miles on the engine and truck. It still running strong. I have noticed now the oil pressure is a tad lower than it used to be. I have been very diligent in the changing oil on a 5000 miles basis and I use Mobil 1 as my choice.

 

[Fastereddie]

It's ridiculous. But unfortunately not uncommon. Check any Dodge or Ram product with the tranny's they use and you'll find only the dealer has a dipstick for them as a special tool. Not to come with the vehicle.

As far as the oil goes, the darn things are sensitive enough if we don't put the right stuff in them, they can set a code and turn on the check engine light before it leaves the lot. We had a Buick Regal the Ford dealer brought over to us just after an oil change they did. They used the Motorcraft Synthetic blend that wasn't Dexos rated. Instantly set cam phaser codes and rattled like mad. Got permission to dump the oil and put the right stuff in it and the rattle disappeared and cam phasers came back into play and started working correctly again. That was the car that proved it for me. Had I not see that thing before and after I would have called BS on oil being the cause. But we were all floored by it.

That’s crazy but I believe it. One time in my younger years I did some rear gears and limited slip for a buddy. I used the correct amount of additive and some cheap store-brand gear oil he bought. He called me as soon as he got home saying it sounded like it was broken. It was a terrible sound coming out of turns. Dropped the cover and couldn’t see anything wrong. After some deliberation I refilled it with valvoline brand and some more additive and it was absolutely perfect first drive. I was amazed.

 

[CyberSniper]

Ecotec3 is different than the old Vortec for valvetrain.

I had 113k on my L76 and no valvetrain problems (no problems at all with the truck except the fuel pump control module, which apparently overheats if you leave the ignition key on for hours repeatedly listening to the radio).

I have 85k on my L86 and no problems yet. I have never been nice to it other than decent PM. I change the oil when the OLM gets to 15% which is about 5500 miles. It gets Mobil1 0w20 (sometimes regular, sometimes extended) and either a M1-212 or PSL22500 filter. 8L90e pissed me off for a long time, at ~30k it got a new torque converter and new style fluid under warranty. Now they just give yet a third kind of fluid for the ones that are slipping too much. It's on its third radiator under warranty and needs a fourth. If you beat on it for a while and come back to idle it blows steam out the passenger side radiator tank.

 

[RubberFloorMat]

I just bought a 20k mile 18 GMC SLT with the 6.2 I consider it to be a Denali without the extra expense.

Im a believer in Schaeffer oils and will be switching to it in a month or so

 

[RubberFloorMat]

Last time I looked Delco Dexos was a synthetic blend, did they change that? I prefer full synthetic, and both Mobil 1 and Penzoil Platinum are Dexos approved.

I wait until they have the sales at Advance Auto Parts, or sometimes O'Reilly. Occasionally they have the 5 quart jug with filter deal. And it includes the better filters with the full synthetic. I buy 5 jugs and it usually lasts me a while and they have the sale again before I need it. Saves me money on filters for the other rides too since I get 2 extra.

I only have less than 30k on it. The only issue I have ever had with it that popped up recently is the torque converter shutter, I need to take it in to see if the warranty flush fixes it or if they will need to replace the torque converter, the powertrain is 5 year warranty. You have the 10L90, hopefully they finally fixed that issue, seems a little ridiculous to me. We have two 2016s and a 2018 8L90 between myself, father and brother in law, and all 3 of them have done it at some point. The dealer has said the latest fluid will fix it, we'll see, I need to schedule it.

I bought mine and noticed the shudder and the did the flush and fill and it’s been perfect since

 

[cuervo]

Mobile 1 full synthetic oils. They make like 3 or 4 of them.

Annual Protection, Extended Performance, Advanced Fuel Economy, Truck and SUV.... etc what in the actual ****?

I assume the anal protection is their premium oil, but all the other types, names, advertisements just confuse the hell out of people.

 

[6872xtc]

I assume the anal protection is their premium oil, but all the other types, names, advertisements just confuse the hell out of people.

This is quite a statement..

 

[folkenheath]

Just to be clear I most definitely like the truck and that engine combination, I just don't like the seemingly common shudder issue.

Since the powertrain warranty is to 100k hopefully they will fix it(I've never had a vehicle with a warranty before), but even if I have to change the torque converter myself after 100k I'd still buy the same truck again, has the best combination of power/torque, efficiency out there I believe. You baby it and you get good mileage, you get on it and it goes pretty decent, I mean, theoretically you hit the speed limiter before you merge on the freeway from the entrance ramp, not that I'd ever do that sort of thing.

And I've towed 10k pounds with it and matched the mileage of a Dmax of the same year. I like the truck.

 

[Tnsejed]

Not much to add but my wife has a 18 Yukon Denali, 6.2l 10l80. Only had one issue with the lane keep assist, which doesn't really matter. Truck has 45k on it and has been excellent. It really is nice as hell. One of the most comfortable trucks to drive.

I can say, I don't believe tuning out the AFM is going to make a damn bit of difference on lifter failure.
https://www.melling.com/wp-content/...GM-LS-Deactivation-Lifter-Issues-3.1.18-1.pdf

On the new trucks with all 8 disabling we will just have to wait and see I think.

With that said though I've never been inside one and just spitballing. All I know is if my wife's motor gives up the ghost I'll just rebuild it, delete AFM, and slap a turbo on it.

 

[cuervo]

To quote that article in part...

To control contamination a small replaceable oil filter is located in the VLOM inlet oil passageway.

Does anyone know if that filter is serviceable without removing the intake manifold?

 

[Tnsejed]

To quote that article in part...


Does anyone know if that filter is serviceable without removing the intake manifold?

I'd love to see a pic of it. 2016 and before appears to be a single filter on the lifter manifold. I'm not sure if that means anything to the 18+ trucks

 

[ZooMad75]

To quote that article in part...


Does anyone know if that filter is serviceable without removing the intake manifold?

If it's similar to the Gen 4 engines, it can be done but it's a pain in the ass. The little screen is in a hole right below the oil pressure sending unit.

If you have skinny arms and small hands one can reach back there and pull the sensor. Then reach in with a pick and pull the screen out.

Nine times out of ten we will get a complaint of low/no oil pressure value on the cluster when that screen is plugged. Engine has oil and is not rattling, just zero oil pressure on the gauge. We run a confirmation with a mechanical gauge hooked in above the oil filter and it checks out fine. Pulled the sensor and found a clogged screen. These are normally same people that went way too long between every oil change to. See the pattern developing?

 

[Tnsejed]

If it's similar to the Gen 4 engines, it can be done but it's a pain in the ass. The little screen is in a hole right below the oil pressure sending unit.

If you have skinny arms and small hands one can reach back there and pull the sensor. Then reach in with a pick and pull the screen out.

Nine times out of ten we will get a complaint of low/no oil pressure value on the cluster when that screen is plugged. Engine has oil and is not rattling, just zero oil pressure on the gauge. We run a confirmation with a mechanical gauge hooked in above the oil filter and it checks out fine. Pulled the sensor and found a clogged screen. These are normally same people that went way too long between every oil change to. See the pattern developing?

Found a good AC delco video here (

), but it appears a Gen 4 motor. He's got the heads off but this should be accessible with the intake on. I guess a big question I have after reading Melling's pdf is that we are operating on a very fine line of pressure. I know hot my wife's truck will idle at 25psi. Operation for lifters is 22psi min. 3 psi fluctuation seems easily achievable throughout the course of an oil change interval. With that said, is there any worry for mistimed operation due to being on the verge of min operational psi on a known good oil change interval engine.