I have not had any issues that I can tell with the AFM system in my 2007 Tahoe, but it is burning about 1qt/~1500 miles it seems. I have just about 170K on it. I never had issues with lifter knocking or anything of that nature. It just decided to start burning oil like crazy for maybe about 1.5 years now. I replaced the driver's side valve cover (new PCV) in hopes that it would help with burning oil, it seems to not have helped. NExt im going to use 1qt of synthetic oil stabilizer and 5 qts of my usual full synthetic motor oil and go from there. But once this motor fails, which I'm sure it will sooner or later, or if I have to replace the cat. converters due to them getting clogged from all the oil burning going on in my motor, I'm giving my Tahoe to Duraburb Inc. in Florida, and have them swap in a GM diesel engine, assuming I hit the mega millions, lol! I'll just have to save up for the diesel engine swap, but I talked with the owner of Duraburb, and he's telling me he has customers with our Tahoes with the swap and they are getting about 25 to 28 mpgs on highway. It pretty amazing. After buying my first diesel car (2013 VW Passat), I'll never go back to gasoline again. In my Passat with the DSG (dual clutch automatic trans), in summertime I'm getting about 45-46 mpgs, and in the winter I'm getting 38-42 mpgs. So its possibly good by 5.3L! we'll see!

 

Your burning oil issue is probably the pistons and rings! GM came out with a TSB #10-06-01-008J regarding these motors and a problem with assembly line production of the engines where the oiling rings are lined up on the piston allowing a huge amount of blow by.

From the bulletin: This condition may be caused by two conditions. Oil pulled through the PCV system or oil spray that is discharged from the AFM pressure relief valve within the crankcase. Under most driving conditions and drive cycles, the discharged oil does not cause a problem. Under certain drive cycles (extended high engine speed operation), in combination with parts at the high end of their tolerance specification, the oil spray quantity may be more than usual, resulting in excessive deposit formation in the piston ring grooves, causing increased oil consumption and cracked or fouled spark plugs (#1 and/or #7). Refer to the latest version of Corporate Bulletin Number 12-06-01-001

So basically they want you to put all this new stuff (new oil baffle and a left new valve cover). If after that it still consuming oil :Re-evaluate the oil consumption. Document on the repair order. If the oil consumption is still greater than 0.946 L (1 qt) in 3,200 km (2000 mi), replacement of the pistons and rings will be required.

Just an FYI

 

Yep, we see ring alignment on the 07 engine all the time, thankfully GM caught it pretty quick and it only seems to effect the 07's and mostly just 5.3.

As for Tahoe (AKA Dirty hoe) economy with a LMM, yes we see 26-28, my wifes 07 Denali XL pulls 25 at 72 mph faithfully with all 3 of our teens and gear

and you can blow the rear wheels off through 1st and 2nd gar!

Gotta love that

 

See guys, I told ya! lol! Hi Eric! Its Rodney from Virginia, we spoke over the phone 3-5 months ago, you probably don't remember, since you have so many customers. lol! Hope business is going well, and hopefully soon enough I'll be a Duraburb customer!

 

I just found this forum and am glad that I did. Our 2007 Suburban, which we purchased brand new in 2007 has experienced all the issues described here regarding the AFM system. I have little doubt that our problem will require an engine rebuild or new engine. I had already contacted GM and they are paying for the oil consumption test and I also had the dealership pull the plugs in #1 and #7 cylinders - and not surprisingly, they were gummed up. Ready to head back to the dealership in a couple hundred miles to see where the oil consumption test ends up after 1,000 miles.

In reading these posts, I can only say that as owners we appreciate any step that GM takes to HELP with the cost of repairs. However, my struggle is the expectation that a vehicle would need a new engine after only 80,000 miles! These are not Isuzu pup trucks that cost $20,000, these were the top end products (minus corvette) that Chevrolet sells!

As an owner, our first years of ownership have been anything but worry free. Outside of the AFM/engine issues, we also have experienced blown hubs at 50,000 miles (and all the damage that goes along with that in the front end), as well as third row seats and brackets that were replaced (couldn't get the seats out!), back up sensors that are bad, UV joints replaced, and now in the midst of trying to get our miles for the oil consumption test - sway bar links that needed replacing. This is a vehicle that we have used to haul our family of 8 - never towed anything, modified any thing, or took it off road for some four wheeling. When it is not driven, it is parked in a heated garage.

My Audi A8, same year and 50,000 more miles (and only a little more expensive when new) is considerably more reliable. This was our 3rd suburban and it quite possibly will be our last. There is no doubt their prices are inline with the competition, but is their quality in line? Have you checked the prices of their new suburbans? For those of us that purchase our vehicles with cash and expect them to last (with routine repairs and maintenance), major repairs like these are troubling. Especially when it is tied to AFM, which seems to be nothing more than a marketing ploy - improved gas mileage would have to be questioned under real world driving.

I hope this forum will help others when their 'low oil' light starts coming on after only a couple thousand miles into an oil change and streams of white smoke at start up. Bottom line, contact GM, they know about this.
Sorry for the rant - just frustrated.

 

Hmm, thought I posted but I don't see it now .... I'll try again.


Kman, you've got a right to be frustrated. $50,000 vehicles that can't make it to 100,000 miles without mechanical problems is a really bad reflection on GM. Suspension problems, 4wd system failure, seat latches are all things that should be engineered to not fail in normal use for a lot of miles.


I said earlier I wouldn't abandon GM over stuff like this, but it does make me wary. Seems like every time I hear about AFM issues it's on a 2007.

 

Kman, did you just recently contact GM about your AFM issues? I'm considering contacting them about my "mystery oil burning". If you contacted them recently, that it gives me confidence to contact them soon! Thanks in advance!

 

Typerod, I contacted them around the end of February. I started by basically going through the GM owner center and then contacting their customer service. Within two days, someone from GM had called me and they set up an appointment with my local dealer. Also, they told me they would pay for the oil consumption test at the dealership.

Of course, when I showed up at the dealership, the service manager had no idea that GM would be paying for it - and I asked them to not only do the oil consumption test but to pull the plugs and look to see if there was oil on the plugs. The service manager at the dealership was a total pain in the a$$ - he tried to tell me how it is standard for engines to use some oil, blah blah blah. While I was at the dealership waiting for the service to be done, I was calling GM to inform them that the dealership found nothing in their notes about them covering the cost of the oil consumption test. My service contact at GM was surprised because it clearly states in my case notes that it was to be covered. Immediately, they escalated the issue to a supervisor who called me to discuss and told me that the dealership would be refunding me the cost of the oil consumption test. Within two days, a check arrived at my house covering the cost.

Now, I have almost completed my 1,000 mile test and will be going back in sometime in April. The bigger question will be, based on the results, how does GM step up?

Brian

 

Thanks Brian! Now I have a better idea of how to handle my case, much appreciated!

 

Well, I spent time at the Chevrolet dealership this morning and have the results of the oil consumption test. After about 1,400 miles, it was determined that nearly 2 quarts of oil were used! This, in addition to the information gathered at the first appointment, led them to the inevitable conclusion that it is the piston and rings that need to be replaced. Now, the first offer from GM and the dealership was for GM to pay 45% of the $2,970 repair bill. I will make a call to the GM call center to see if there is anything else.


I'm not sure what to do - a little too late to try and sell since it now smokes like crazy at start up. No good options.


Brian