2012 with fouled plugs- what else to expect?

MPFit · November 4, 2014

2012 Sierra 5.3L AFM Crew Cab SLE

Bought at 20k miles - did oil change, waited 5k miles to do next change. Was 1.5 QT low. At 25250 miles CEL came on, went to dealer and had Spark Plugs 1 and 7 replaced. New valve cover also. Rough idle since I've owned it, never able to recreate at dealership.

I love the truck, but I, as many, am worried about the longevity of this engine. What should I keep an eye out for as far as getting this engine covered under warranty and keeping it for as long as possible? I like the idea of Range AFM delete, but never done any tunes before and don't want dealership to have a reason to void this 'oh so necessary' warranty! Dealership hasn't ever mentioned oil consumption test or anything aside from; we replaced your plugs and a valve cover.. I feel after reading all of this that they aren't really keeping me in the know of what's happening to my truck! Any suggestions or tips I should be aware of?? Thanks so much!

chupe442 · November 4, 2014

Is there another dealership that you could take it in to? Personally, not a fan of the Range AFM. I went full Black Bear tune and never looked back. But you have issues coming into the AFM delete or tune thought process. With 2 plugs fouled, you should have thrown a code for misfire. IMO... Good luck!

MPFit · November 4, 2014

I could take it to another dealer yes, next time I have a problem I'll do that and see where it goes.

If I'm reading it right it says Code C0561 00

And Code P0300 00.

They installed spark plug and cover

02270-BPCKT plug and

00386-PCT cover

Seems to be better now, only been 10 miles though!

MaverickZ71 · November 4, 2014

Welcome to the wonderful world of GMT-900 (2007-2013 Silverados and Sierras) AFM engines. Accordint to my GM service manager, these include 2 types of engines: those who already have this problem, or those who will have this problem.

The revised driver's side valve cover includes a relocated PCV orifice in an attempt to keep the AFM system in your engine (shuts down to 4 cylinders when coasting) from burning too much oil. There is also an oil 'deflector' they can install in the oil pan. The AFM system causes the excess oil spray to burn oil, and to foul the plugs and cause the MIL/check engine codes. These engines have been known to feel like they are 'missing' at idle, even when they are running as smoothly as they can without throwing any codes. I've been told that the firing order was changed for the AFM system, and this, along with a special cam for the AFM system, contributes to the relatively rough idle. Like they say, the Chevy smallblock was great until the government (fuel economy regulations) got into it.

If you install a RangeV8 module or otherwise turn off the AFM feature via a new PCM tuning (a lot of people on this forum use Blackbear), run some AutoRx in your oil to clean your piston rings, then use Dexos-certified engine oil (semi- or full-synthetic) and some Chevron Techron fuel system cleaner to clean your oil-fouled plugs, you should be good for a long time, unless your engine has other mechanical issues. At the most, you may have to have new pistons/rings to get the oil usage stopped. Some of the folks have also installed an oil catch-can in their PCV line and have reported positive results.

chupe442 · November 4, 2014

I could take it to another dealer yes, next time I have a problem I'll do that and see where it goes.

If I'm reading it right it says Code C0561 00

And Code P0300 00.

They installed spark plug and cover

02270-BPCKT plug and

00386-PCT cover

Seems to be better now, only been 10 miles though!

P0300 is the fouled plug.

C0561 is the stabiltrack that seems to be defaulted, when anything else goes out it sees it as well.. It will reset with the other without any parts from what I have seen..

Not sure that AFM delete will cure your problems since it has already started lose or burn excessively. I would say to keep an eye on it and get it either back into the dealer you had it at (you have history there) or a different dealer and don't back down until they remedy it for you.. Good luck!

MPFit · November 5, 2014

Thanks guys.

So you think I should take a look at the new pistons and rings prior to making a move for the AFM Delete?

Assuming that this will halt the oil consumption problem? Then from there using the AutoRX and continuing to do so as PM, then finally shutting off the AFM?

Since I'm still under warranty, bumper to bumper until this summer, and Powertrain until 2017, my thought was to simply continue to drive it and- as they arise- hold the dealership responsible for fixing the truck. Otherwise I'd swap the pistons and rings now, and delete the AFM (at my own expense obviously)...

This oil catch can sounds like a great idea also. My truck is so young at 25k miles I'd love to hit 150-200k but I am just not sure that GM makes trucks to hit this mark anymore!

chupe442 · November 5, 2014

At this point I would keep a close eye on your oil consumption. If it goes away with what they just did. Have some fun and either order up the Range, or go full on tune and drive it til the wheels fall off (150-200,000 miles..). If it starts to show consumption, then get it in and make them address it properly..

MPFit · November 11, 2014

So I did a fresh oil change, threw in some Techron, and added the Auto-RX.

As I stated before the car is running great, but it has been since I got it back from the dealership with spark plugs replaced.

I ordered the JEGS air fuel separator. Got the hoses, should come in today and I'll post pics of the install.

Just to get familiar with the connections, I found the PCV Orifice hose that connects to the catch can, and disconnected it..

Wow, the entire hose was lined with oil.. Enough that when I removed the connection there was oil dripping onto the 3/8 connector coming off the Orifice.. I know people have variable results with the amount of oil the catch can collects, but I definitely did not expect to have oil basically coating the lines and connections.

When I go to install the Catch can tonight I'll take some pics of the oily connections and everything.

MPFit · November 14, 2014

Installed catch can- little hiss from the filter but checked for leaks and nothing. Looks great, kinda made it flush mounted and ran hosing around backside and along wire housing tubes to make it look inconspicuous (I'm anal about engine hah)

Gonna try and figure out how to post pics

MPFit · November 21, 2014

UPDATE - 200 miles on since catch can install, and roughly an ounce in the can.. Ugh- all that oil was getting sucked up prior to this install, which probably isn't even collecting all of the oil! Sorry I can't post pictures, not sure how.

Just curious what I can use to clean the filter itself, not the polycarbonate housing (water and soap for that)

Gurrzt · November 22, 2014

Is there another dealership that you could take it in to? Personally, not a fan of the Range AFM. I went full Black Bear tune and never looked back. But you have issues coming into the AFM delete or tune thought process. With 2 plugs fouled, you should have thrown a code for misfire. IMO... Good luck!

+1 on this

MPFit · January 13, 2015

Just an update:

Catch can still catching small amounts of oil condensation..

I will admit, that the amount I catch is much less since I've run the AUTO-RX through..

Not sure if it is related as I don't know much about the AUTO-RX..

I have decided to become more diligent with oil changes: I change every 3000 miles as if it were conventional (I use Mobil1). It leaves with 50-60% life according to the OLM.

I don't care that I could go longer, from the research I've done the high quality oils like M1 help clean the engine and I'd prefer to spend an extra 35$ every 3000 miles for peace of mind, and also so I can track any loss of oil more accurately.

Fact is, the oil consumption has dropped in the past 8000 miles, as well as amount caught in the catch can. Don't know if it is due to the Auto-RX, or simply the fact that my engine likes the M1 oil (Don't know what previous owner used for the first 20000 miles).

RangeV8 module has also been ordered, will be here by Friday; I'm very excited for this also! Thanks all for the help and tips, at 30k miles now (in 10k in my 7 months of ownership) I am getting more and more confident this truck will last the test of time with me- fingers crossed, I really love this truck.

Cowpie · January 15, 2015

Someone mentioned, I believe on another forum, of doing a couple of thousand miles with a HDEO diesel oil to help clean things up internally. A CJ-4 5w30 synthetic diesel oil would provide a boat load of detergent to help clean things up. And it should be SN rated as well, which would work in these motors. Not like one would be using it all the time anyway. If mine had these issues, I would sure give it a try for a couple of 2000 mile oil changes then go back to a full synthetic gasoline rated oil.

As a side note on all of this, I use a Schaeffer 9003D 5w30 full synthetic in my 2013 5.3L. It is not on the "approved" dexos1 list, but claims compliance. I have never worried too much about the dexos1 thing. Schaeffer has been making quality oils and lubes since 1839, longer than anyone else in N. America, so I think they have a handle on how to do it. My motor uses about 1/4 quart (8 oz) of oil in 6000 miles. Of that amount, the catch can on my PCV line captures about 6 oz of oil and crud. So the motor is only "using" about 2 oz of oil in 6000 miles, which is my comfort level on oil change intervals. Yes, AFM is disabled and has been since 240 miles on the odometer.

The Auto-RX and synthetic may just do the trick. If you have seen reduced consumption, it might just come around for you. Once you run for a while with the AFM disabled, and continue to do what you are doing, the problem might just clear up. Too bad we have to come up with all sorts of techniques and methods to overcome problems from a lousy design.

gnet158 · January 15, 2015

Don't mean to hijack your thread, but dose Auto-RX really work or is it just "snake oil"? I'm interested in trying.

MPFit · January 16, 2015

I can't give a statistical response to that as I did no oil tests before or after. It's basically lanolin oil I believe.. I added half a bottle to two oil changes. Never threw any codes or acted any different then running regular oil what so ever. Again, with no actual data to back it- I can't say if it's snake oil or not. I'm pretty practical, and aside from liking mobile 1 I have no real loyalty to any of these products. That being said, my oil consumption has dropped probably 50% since I ran the AutoRX.. But I was on my 2nd or 3rd oil change with Mobile1 so it could have been the better oil (Assuming original owner used the synthetic blend from GMC..) that gave me these results. I didn't single out any of the products since I threw basically everything suggested to me at the truck from this thread to stop the consumption. If you're already running M1 oil, give it a try.. See if it helps. It supposedly works better with conventional oil but whatever. I also did the Techron pre- oil change to throw a little more confusion as to what caused the drop in consumption.. good luck!