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Chevy Silverado and GMC Sierra Active Fuel Management Problems



  • Sorry to hear of your lifter troubles. At least your engine still functions. My advice is to trade it in on the Ford truck you've been considering while you can still realize some value. Once the general public comes to realize Chevy's AFM design is flawed, and that GM will not help outside of warranty, you can expect the value of used GM trucks to diminish - considerably. Right now, there is limited knowledge of the situation, noting that you were unaware when making your purchase.

    Best of luck & happy holidays.
  • Just had to have my engine pulled for lifter and camshaft replacement. 118k. I know, is out of warranty. CS told me that like 1,000 times. Bottom line is no way should a chevy truck need to have engine pulled this prematurely. Dealer mechanics say it is NOT a normal wear and tear issue, it is NOT a lack of proper maintenance issue, but it IS an engine design issue. While Chevrolet likes to pat themselves on the back by helping with some of the cost of the repair, I was still left with paying for the majority of the repair....even though it is a design flaw. I have purchased Chevy trucks brand new since I was 24 (able to buy one on my own) since 1995 and bought one every 4-5 years. My dad was a die hard Chevy fan since his first purchase in 1957. NEVER again for me. They turned their back on me and therefore I am turning my back on them as well. I am sure they are not loosing sleep about it, but it is what it is. I will be making sure that everyone I know in the vehicle market will know the specifics of my experience and everything that I learned about this "Design Flaw" before they make a purchase.
  • chuck1chuck1 Posts: 1,405
    edited December 2012
    How about other 08's like yours where there are not any wide spread issues? (They have not been posted).

    Don't know how many trucks GM sold with the 5.3 in '08-but it had to be at least 30,000 units, probably closer to over 40,000 units.
  • Hi churchy25,
    I had a problem with the 2011 Silverado I bought new. From day one, the AFM wouldn't work at highway speed (70 MPH). I tried and tried to get them to fix it. They even acknowleged that there was some sort of drag on the engine that was keeping it from changing into v4 at hwy speed. Bottom line is, GM told me they were not going to do anything about it and I could do with it whatever I wanted to. My only way out was to sue or sell the truck. I traded it in on another vehicle about two months ago. It goes without saying, I didn't trade for another GM vehicle. I couldn't get GM to stand behind it. I felt like I couldn't trust them any more. I only had 12,000 miles on it? The mileage I was getting was 14 city 15 cith/hwy combined 16 highway only.
  • chuck1chuck1 Posts: 1,405
    String also needs to tell you that he didn't need the truck anymore for the primary application he originally purchased it for.
  • chuck1,
    Do you own a Silverado or Sierra with an AFM engine?
  • churchy25,
    all I can say, in the words of Blake Shelton(country singer coach on the voice, aka, entertainer of the week), is "dang it". I feel your pain. I've also left GM for another brand - a RAM. Might as well join me and probably 30,000 or 40,000 others in the future according to chucky1. When you add in the cost of engine replacement, a GM truck can't compete with Ford, Toyota or RAM. It is what it is.
  • chuck1chuck1 Posts: 1,405
    edited December 2012
    I own a 2011-5.3 with the AFM. I am currently on a cross country trip and have driven over 2,500 miles through all kinds of terrain pulling a 5,000pound 28foot travel trailer. The mpg towing has been between 10 and 14 depending on terrain, headwinds, etc. It's probably safe to say that no one here on this board is in the process of using their truck to travel across the country towing a trailer.

    I have also driven the vehicle 3 times from So. Cal to Salt Lake City, UT ( and back-non towing) and have achieved 20 mpg consistently with the AFM in 4 cylinder mode. It's great feature.

    I am the first to say the 6 speed transmission I S LESS THAN REFINED.
  • Well I ran 2 cans of seafoam with a tank of 93 octane gas. The spark knock stopped, so when the tank was nearly empty, I put 10 gallons of 87 octane in. The spark knock has returned. My problem may be something simple like a partially clogged fuel injector, slightly faulty MAF sensor, eroded spark plug(s), faulty coil pack, etc, etc. I just don't have the time to chase the problem or the money to throw parts at it. The salesman from the dealership did call and ask about how the truck was doing today, but I was working and the call went to voicemail. I will call him back tomorrow and see if they want me to bring it in. What's strange is the new 2012 Silverado I drove with 30 miles on it spark knocked some. Of course the fuel in the tank may have been in there over a year, I guess. I wish the dang check engine light would come on so I'd know where to start looking. The engine also "ticks" at idle with the 87 octane fuel, not as much if at all with 93. Leaning towards a partially plugged injector...but I dunno. Bought this truck because I was tired of working on the 94 chevy and 98 dodge I sold to buy this one. Oh well.
  • Emailed dealer where I bought the truck and told them the fuel treatment that was recommended by their service manager did not work to stop the spark knock or whatever it is. I have yet to see a response. I need to run this fuel out of the truck and try 93 octane again and make sure the noise stops. I'm not 100 percent certain it isn't lifter noise instead of spark knock I have an appointment with another dealer set for 12/27. If they tell me they can't hear the noise or the noise is normal, I'll be trading the truck for another brand. I didn't buy the truck new, but I laid down over $20k cash, and I don't intend to drive it around and listen to it make ticking sounds. It's frustrating because I'm sure I will lose money trading it, even though I've not had it long enough to even receive the title from the state. Started hearing the noise before I even got a tag on it. Sheesh! What a drag. I usually only trade vehicles once every 8 or 10 years. I try to get 200k miles out of them. I seriously doubt this one will make it that far since it only has 54k now. If I don't get it resolved the 27th, I'm f150 shopping. Ugh...I dread dealing with trading again.
  • First of all-I am sorry for all your troubles. There are a couple of things to learn from this exercise in frustration.
    1) A USED VEHICLE IS A USED VEHICLE FOR A REASON. Sometimes the owner gets tired of it, or doesn't need that type of vehicle anymore, OR there is something wrong with the vehicle he is trading in and wants to get rid of it. Clearly, the last statement is applicable in your situation.

    2) "Certified" from any dealer or manufacturer is meaningless. It's still makes sense to have the vehicle checked out PRIOR to purchase by your own mechanic. It's called BUYER BEWARE!

    I would explain very clearly to the selling dealer that you wish for them to take back the truck ( at full purchase price) and put you in to another truck. If they refuse, explain to them you will plaster their name on every Internet site you can find to explain what happen to you. Be careful not to be slanderous,as they can sue you. Just explain YOUR CIRCUMSTANCES and that will be enough to keep people away or have second thoughts about buying from them.
  • I appreciate your input, and may indeed follow your advice on trying to trade with the dealer. However, by your reasoning, the used vehicle I would be trading mine for would also be used for a reason, right? I checked the truck out the best I could. Drove it quite a while, even crawled under it to look for leaks. I doubt a mechanic checking it out would have noticed anything. I do all mechanical work on my vehicles myself if I can. I can and will do anything short of transmission work or internal engine work. It pretty much only does it at full operating temp in V4 mode, which it doesn't stay in very long unless you try to make it. Hard to catch that right off. At this point I'm trying different gas stations and octanes to see if anything changes. Also going to let the other dealership have a look at it the 27nth and go from there.

    BTW, one owner truck and I called the previous owner who said he never had any issues but admitted his hearing wasn't the best (older gent).

    I'm sure you're a nice enough guy, but for some reason you seem to want to put blame on the owner, not the vehicle, manufacturer, or dealership. . I'm well aware that buying a used vehicle is a gamble, but a certified used vehicle comes with a warranty, so if something's not right, the dealership needs to fix it in a hurry. No questions asked. Certified should mean....certified.

    Honestly, if I had bought the truck new, I'd have quite a bit more money invested, so maybe that would have been the bigger gamble. The reason I don't buy new is I can't afford it unless I finance it. And to me (most will disagree), financing a new vehicle is just throwing money away since they drop in value so much the first few years / miles. Take your truck, for instance. How many miles on it? If it starts having problems in 4 or 5 years, regardless of the mileage, you've lost quite a bit of money if you try to sell or trade it. I guess if your truck starts to make the racket mine does at 50k miles the argument could be made that you didn't do enough research on the AFM system before you made your purchase. BUYER BEWARE, right?
  • gmcustsvcgmcustsvc Posts: 4,055
    Keep us posted on how your appointment goes tomorrow! If you would like for us to check into anything further for you, please contact us at (include your name, contact information, the last 8 digits of your VIN, and a summary of the situation).

    Sarah, GM Customer Service
  • Well, the visit to the dealership went about as expected. The service manager got in and we drove for about 5 minutes (with no scan tool). The service guy said he didn't hear anything. Which isn't surprising, I didn't hear it that often in the 5 minute drive either. It doesn't make the noise constantly, so no surprise it wasn't heard by him in 5 minutes. He did say the AFM motors did make noises different to a regular engine. I asked him why. He said he didn't know, could be partially clogging oil passages....which didn't help my feelings much. Lol.

    The dealership where I bought it will trade on another truck, but not at the value I purchased this one for. I asked the salesman why I had to lose money trading it back to them. He told me they expected 1500 dollars in repairs and were allowing for that. Total BS as they will no doubt sell it as is again. He offered to trade my truck for a 2012 new truck similar to mine with the smaller V8 (no afm) and less options for an additional 9k. I told him I'd do it for 5k, no additional fees, otherwise I'm done with them. He said hed let me know, but no word yet. Also have a possible 2wd drive Tundra I may could trade even for. If the Tundra or the 2012 base model don't pan out, I suppose I will run higher octane fuel to mask the problem and trade this truck later. A bit tired of salesmen right now.

    Sarah, thanks for the interest, but what can you really do? Let's assume for now that I am correct and the engine has a random misfire at times due to a weak lifter or some other engine component. Let's assume the misfire could be seen if a technician drove the truck with a scan tool hooked up to the OBD port. Is GM going to put new lifters in my truck because of a missfire that has not set an OBDIII code yet? I doubt it. The truck operates well now, and a lot of people wouldn't notice the noise. The problem for me is the noise is probably caused by a mechanical fault that will reduce the life of the engine. So what could be done? Extend the warranty? Regardless, I will be e-mailing you the requested info anyway. I doubt much will come of it, but at least I will have a record of it.
  • I'm posting this seperately to see how many others have this noise.

    I have a 2008 Sierra with 50k miles with a 5.3 and AFM. I recently purchased it as a certified used vehicle. I recently noticed a ticking, or clicking, or gravel in a tin can sound when the truck is in V4 mode under light throttle. The noise is also present when accelerating out of V4 and into V8 mode. Higher octane fuel seems to reduce the noise. I have not had a dash "service engine" light come on yet. I have test driven several other vehicles with the 5.3 and afm. In most, I have heard this noise, but to a lesser extent than my truck. I believe the noise is spark knock, or predetonation caused be faulty lifters and/or valves. Has anyone else noticed the noise in their 2007-2013 Silverado, Sierra, Tahoe, or Yukon with a 5.3 V8?
    You might want to save yourself some trouble / grief and go ahead and throw in the towel now. If there is no trouble code, you can definitely forget it. When there is no trouble code, that will be their excuse for denying there is a problem, even if that particluar problem would not normally throw a trouble code (they don't expect that you will know the difference). They will just check with GM and they will deny the problem. I really think they don't know where to start looking without that trouble code.
    Now, some other poor unsuspecting soul has my problem and the endless battle with GM. I finally had to trade mine in for another vehicle. (not GM, though). You may get lucky though, and it will fix itself. Good Luck!
  • jswain2jswain2 Posts: 16
    Yeah, you are probably right. I mainly visited the dealer this last time and e-mailed customer service for documentation. Just in case I wind up keeping the truck and the engine fails outside of warranty, possibly I can tie it back to this.

    I suppose all vehicles have problems. I just seem to get the ones that have the problems. If I buy a Dodge, I have transmission problems. If I buy a Chevy, I have lifter issues/noise. The worst part of it is, I really do like the truck. At this point, I don't really care what I drive. I wish I had my 500 dollar 94 Z71 back. It only got 1 mpg less than the 2008, and if the lifters made noise (I had one lifter that tended to stick), I just put a quart of trans fluid in the engine oil. I'm not sure if it was good for the engine or not, but it would make that lifter silent. And since I only paid 500 for the truck, it didn't matter so much. Shame I have so much more invested in this one, as I'm sure I've got some trans fluid somewhere in the shop...probably Dodge trans fluid lol.
  • I have a 2007 Silverado LTZ 5.3 with AFM. When I first got my truck a lot people commented that is had some engine noise (slight lifter noise), but it wasn't super bad just a little pathetic for a brand new truck IMO. Another issue was my truck would vibrate noticeably when it dropped from V8 to V4 mode. The dealer said it was normal, bunch of BS.

    My truck has had its fair share of problems in addition to above: motor in the passenger side mirror failed, two speed sensors failed, had some electrical issues where all the lights would flicker in the truck while would shut off, battery died, etc. Almost like my truck was shorting out. Since the last battery install, I haven't seen this issue surface. I've babied my truck, I don't take it off road or romp it. Always run super unleaded.

    The issue is I had my truck in some colder weather recently, i live in Arizona and I was up North. I had my truck parked on a slight incline of maybe 5 percent overnight. I went out to start it up in the morning, boom severe lifter a ticking time bomb. It took literally 5 minutes before it quieted down...while I was like you've gotta be kidding me. The really kicker, my warranty just expired because my truck is 5 years old. So I only have 70K miles total on the vehicle and it probably looks better than most trucks that are a year or two old. I've babied the hell out of it.

    The issue doesn't happen on every start up...I would say it happens maybe one out of every 7 start ups. However, when it does happen it is embarassing, loud, just makes my blood boil. I paid a lot of money for my truck, I just paid it off in full, the warranty just expired and it appears a lifter has gone bad...just my luck. It's almost like it depends on where the motor stopped on shut off if its going to start up with lifter noise or not, if that makes sense. It's like rolling the dice on every start up.

    Does anyone have any advice...being that I'm now out of warranty, this GM issue could get pricy. I know they had more issues with AFM on 2007 models than some of the new models. I was told replacing all the lifters with LS1 fixed - non AFM lifters, replacing the cam, and doing a tune with an AFM delete would solve my issue. However, this a $2,500 job. I don't want to play around with the dealer that is going to put band aids on my truck and in the end cost me probably more money. Please advise you have some solid advice. I'm getting ready to head to the dealer, however, they told me before coming in if they can't hear the lifter noise they can't help me. What am I supposed to do, spend the night for a week at the dealership and be there when they start it up? So they try to diagnose it really quick, while it's making noise.

    To GM, I paid 40K for this truck, does this sound right? It was my very first brand new vehicle buy as I'm a younger guy. So, plenty of more trucks to come in my lifetime. Would you be upset? I've been a loyal GM guy and my family has always driven GM and now I'm questioning why. This truck should make it more than 70K without major lifter noise, especially as it's been well taken care of. I've always run Mobil fully synthetic motor oil, mobil oil filters. This is insane! I've read too many stories of lifter issues.
  • gmcustsvcgmcustsvc Posts: 4,055

    We certainly understand why you're frustrated and apologize that you're having these troubles with your Silverado. Was the dealership able to hear the lifter noise?
    Let us know if we can look into anything further for you!

    Sarah, GM Customer Service
  • jswain2jswain2 Posts: 16
    Mine has a slight tick also, 2008 with 54k miles. Occassionaly, when the weather is cooler, it will tick for a split second (like 2 loud ticks). Also spark knocks like crazy on 87 octane, does ok on 89. I'm pretty sure its all related to the lifters. I drove a new 2012 that had worse lifter tick than mine though, and it would spark knock changing from V4 to V8. Probably why the dealership still had it. One of the service managers also told me mine was pretty quiet. He said half of the new ones would have a tick at idle. Great.

    I would be careful taking it to the dealership out of warranty for repair work, going to get expensive in a hurry. And from what I've seen, the dealership doesn't necessarily do better work than an independent shop. But you may have a good service dept at your dealership. Mine is under warranty (certified used), and I can't get anything done. Apparently service tech's have poor hearing, say they don't hear the spark knock, its normal, etc. There are a few TSB's on AFM lifter noise, I imagine you've read those though.

    I just bought my truck 6 weeks ago or so. I looked at trading it, but I'm going to lose too much money. I plan on driving mine until it gets worse or starts using oil, then I will trade it in. As long as the lifters are loudest with the engine cold, I figure I can get long gone before the dealership cranks it in the AM. One things for certain, if the lifters fail and I have to replace them, I would not want the afm motor, would prefer the lifter and cam swap you mentioned. The 5.3's without AFM seem to last a long time.

    The crappy part about it is you, with 70k miles, nor I with 54k miles should have to even be thinking about our motor yet.

    Keep us posted, hope you have good luck.
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