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Discussion Starter #1
Just bought the wife an 07 Tahoe with the 5.3 that is flex fuel and is equipped with the active fuel management (V4 mode). I just stumbled up on all this info on an outdoor forum thats talking about how these engines are burning up oil and many are needing new pistons because there is a lack of lubrication when the AFM kicks in. Is this old news? There were GM bulletins posted about it. Many people on that forum have problems with the 5.3 in the NBS trucks/SUVs

My VIN says it has a iron block. Unless i read it wrong, its the aluminum blocks with AFM that have the issue. Does the iron block not have this condition even when equipped with AFM?
 

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if that is the engine iam thinking of they have a tsb out on them that talks about the right side head got nicked when the machine put it together...
 

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I Sell Fireworks!
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I have heard of this too and would be interested in any info. A friend of mine has an 08 with the 5.3 in it and he got a warning light last week for low oil pressure. He pulled over and after towing it to the shop they determined he was FOUR quarts LOW on oil. He had his oil changed about 3500 miles before this happened. No leaks, they determined it was burning oil. Sadly they said there was no damage and he needed to watch his oil level.
 

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Discussion Starter #4
thats terrible. if i understand all i read right, its the aluminum blocks that have the problem. Its directly related to the AFM system but all i can guess is because of the difference in internal manufactureing characteristics between an aluminum an iron block, the design of somthing in the iron blocks somehow doesent present this problem. There has to be some sign of oil burning besides the obvious for your buddy with that much consumption. has he noticed smoke from the exhaust or alot of soot on the bumper where the tail pipe is?
 

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my boss had an 07 avalanche with the 5.3. When it had less than 15k miles on it, it was using quite a bit of oil, and had been to the dealership four times before they replaced the motor, I think this issue was only for a couple of years and if your tahoe is an 07 also maybe its having the same issue
 

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The wife has an 07 Tahoe with about 120,000 miles on it. I use amsoil and change the oil every 7500 miles. It gives a warning at about 5,000 miles that the oil is low. I add about a quart and go. It is not a flex fuel.
 

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All I know is that the 2009 suburban I've been driving is a turd and has developed a knock in the last two weeks with only 40k miles.
 

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Discussion Starter #9
i wish i knew if all these mentioned had aluminum blocks. i dont know if it was rare to have the iron block or not but either way, thats whats in the tahoe i bought my wife. we havent had it long enough for me to determine if its burning oil or not. guess we will see. im just shocked i havent heard of this earlier, either through friends or hearsay.
 

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I had an 09 halfton with the 5.3(flex fuel and active fuel management) I never had any issues with oil use. Hell I never had any issues with it! It was a great truck and did everything I asked it to do I just wanted a dmax. the key to that motor is keeping the oil changed. IIRC the active fuel management works off of oil pressure
 

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Diesel n00b
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My friend bought an 09 1500 with the 5.3 and at 45k miles, it started knocking badly. First thing I told him was to check the oil. Long story short, they replaced the cam and all the rockers on the right side of the motor, thankfully he was still under warranty.
 

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Hang it!...Fire!
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my squad leader has a 07 5.3 and he hasnt had any issues with it
 

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I had an 09 halfton with the 5.3(flex fuel and active fuel management) I never had any issues with oil use. Hell I never had any issues with it! It was a great truck and did everything I asked it to do I just wanted a dmax. the key to that motor is keeping the oil changed. IIRC the active fuel management works off of oil pressure
I will say that with the strange knock that I caused it to developed the thing still runs perfect. Apparently it's common for the 5.3 to developed a knock/piston slap over time but it doesn't cause any real problems..? Idk but it's gutless..
 

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I hate the 5.3. Chevrolet made a big mistake when they quit putting the 5.7 in there trucks. My 2002 z71 slung a rod on start up with a little over 100,000 miles. The 5.3 is week as pond water to.
 

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I hate the 5.3. Chevrolet made a big mistake when they quit putting the 5.7 in there trucks. My 2002 z71 slung a rod on start up with a little over 100,000 miles. The 5.3 is week as pond water to.
The 5.3 and 4.8 are great engines, not sure about the new ones that go to a v4 mode though.

I know many people with 5.3s with LOTS of miles that are still running, Hot Rod Magazine put 1200hp on a stock bottom end of a 4.8 trying to blow it up.
 

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i have an 02 with the 5.3L, and it doesnt burn a lick of oil. also any of you that are having a knock on a cold start, that is from the vortec motors design. the piston skirts are shorter so they actually rock back and forth in the cyclinder walls until the rings get hot and expand. then the knock goes away.
 

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Nothing is wrong with the 5.3, they run forever and are NOT underpowered like the shit talkers say. My buddy has a 00 halfton silvy and that thing moves, hasn't had any thing comparable touch it. My sisters half ton 5.3 sierra runs good too, never seen one that runs bad.
 

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I hate the 5.3. Chevrolet made a big mistake when they quit putting the 5.7 in there trucks. My 2002 z71 slung a rod on start up with a little over 100,000 miles. The 5.3 is week as pond water to.
your kidding right? the LS platform is one of the best engine designs that GM has produced. yes the 5.3 can be a dog in stock form but mods are endless and they can take a lot of power. you should do some research....
 

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i agree. my 02 5.3 has yet to let me down. towing close to max up and down hills all day, working the fields through mud, snow, sleet, ice, and god only knows how much rain. she starts in 110 degrees and 10 degrees on the first try. as far as a chevy gas motor in a half ton, id take another one any day.
 

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The guy i bought my dmax from has a two wheel drive early 2000s model with over 400K on it and hasn't done anything cept change oil and some sensor. No internal motor work
 
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