2008 Nbs 5.3 Lifter Failure / Camshaft Deadspot?

Gduck24 · November 24, 2009

I just bought a 08' chevy crewcab 4x4 5.3l with 100k. I know thats a lot but i figured by now gm had their stuff together on these engines. I guess not. I had the truck almost 3 weeks when i suddenly started hearing what sounded like a dropped valve to me. I immediately stopped driving and had it towed to the dealership. I told them what i thought was wrong and they proceeded to run an altenator test, transmission test, and then tell me its "inside the engine". Duh! After much arguing that they might have damaged the engine more they finally decided to go inside to find the problem. They come back to me today and say that a lifter has failed and the camshaft has a flat spot on it. The noise was an on/off kind of noise. Wouldnt a worn camshaft be a gradual problem/noise? Now they say they will knock off 1000 and fix just the lifters and the camshaft for 2950. I think this is comeplete BS! I can get a complete rebuild for 3500 done or an engine with 15k put in for the same. Does anybody have any input or advice on the situation? I did buy the truck as is - but i didnt think the dealership would put my truck through the ringer when i warned them of a critical failure. It was knocking like a SOB when i got it back after they checked it out the first time(externally).

My engine VIN is "M". I think it is the stupid AFM i didnt know anything about until i found this forum. Is this M type rare? The mechanic i used to use says it is.

Nytemare · November 25, 2009

Its obviously out of warranty....just get a new performance cam lifters and non AFM rocking arms and swap it in...you will probably do it for around a thousand. Than get Blackbear to reprogram your ECM to get rid of the AFM.

I don't know if you have the 30-day clause where you are. I know we do in some parts of Canada, but...you said it yourself man...Bought AS IS...you really have nothing to go back on.

AK FiveO · November 26, 2009

My 2009 Sierra has an "M Code" 5.3L engine. The "M" code denotes the "Aluminum Block/Aluminum Heads/Non-Flex Fuel" engine. They are not rare, and I haven't heard of this problem in the newer 5.3L (of any code). It doesn't seem impossible for a lifter to fail (especilly since that 5.3L has 4 electrical lifters in it for th AFM). To "flat-spot" a cam lobe though ...seems like it would have had to of been knocking like hell for awhile to do that (like since before you bought it), so I would have thought it sounded bad when you test drove it at purchase time. Sounds like someone may have "over-reved/worked" the engine ...then traded it in when it started sounding shitty? Or ...the service senter could have made a small problem big when they tried to diognose the problem.

Regardless ...looks like you screwed (unless you bought an extended warranty at purchase time)??

And yeah, I turned off the AFM on my truck with my Diablo Sport Tuner ...because I paid for 8 cylinders!

Nytemare · November 26, 2009

My 2009 Sierra has an "M Code" 5.3L engine. The "M" code denotes the "Aluminum Block/Aluminum Heads/Non-Flex Fuel" engine. They are not rare, and I haven't heard of this problem in the newer 5.3L (of any code). It doesn't seem impossible for a lifter to fail (especilly since that 5.3L has 4 electrical lifters in it for th AFM). To "flat-spot" a cam lobe though ...seems like it would have had to of been knocking like hell for awhile to do that (like since before you bought it), so I would have thought it sounded bad when you test drove it at purchase time. Sounds like someone may have "over-reved/worked" the engine ...then traded it in when it started sounding shitty? Or ...the service senter could have made a small problem big when they tried to diognose the problem.

Regardless ...looks like you screwed (unless you bought an extended warranty at purchase time)??

And yeah, I turned off the AFM on my truck with my Diablo Sport Tuner ...because I paid for 8 cylinders!

LOL...my Grampa always said, since the conception of the 4-cyl engine...."double the cylinders, double the gas, double the comfort"!!!

alwcurlz · November 26, 2009

As for buying used like that, I've bought only with the consideration that I would give myself space, repair money wise to fix what may go bad and still be within comparable value with a same vehicle which is more expensive. I know this is hindsight advice but, my 2¢.

Some other thoughts I have here....In your case, with the expected expense to rectify the situation, I would take it to court. I would make a point that you took your vehicle to the repair shop to diagnose the problem and they performed tests you didn't request but eventually verified the problem. If the dealership says it was as is and it did not make the sound when purchased, then you could say the dealership performed testing which damaged the engine and they are liable. If they say the vehicle had the problem to start with, then you could say that you would not have purchased the truck if it had the problem it has now. Not sure if that info will help but, good luck for your situation.

VMax2007 · November 26, 2009

My 2009 Sierra has an "M Code" 5.3L engine. The "M" code denotes the "Aluminum Block/Aluminum Heads/Non-Flex Fuel" engine. They are not rare, and I haven't heard of this problem in the newer 5.3L (of any code). It doesn't seem impossible for a lifter to fail (especilly since that 5.3L has 4 electrical lifters in it for th AFM). To "flat-spot" a cam lobe though ...seems like it would have had to of been knocking like hell for awhile to do that (like since before you bought it), so I would have thought it sounded bad when you test drove it at purchase time. Sounds like someone may have "over-reved/worked" the engine ...then traded it in when it started sounding shitty? Or ...the service senter could have made a small problem big when they tried to diognose the problem.

Regardless ...looks like you screwed (unless you bought an extended warranty at purchase time)??

And yeah, I turned off the AFM on my truck with my Diablo Sport Tuner ...because I paid for 8 cylinders!

"Electrical Lifters" huh?

They are hydraulically actuated and the hydraulics are controlled by a solenoid.

AK FiveO · November 26, 2009

My 2009 Sierra has an "M Code" 5.3L engine. The "M" code denotes the "Aluminum Block/Aluminum Heads/Non-Flex Fuel" engine. They are not rare, and I haven't heard of this problem in the newer 5.3L (of any code). It doesn't seem impossible for a lifter to fail (especilly since that 5.3L has 4 electrical lifters in it for th AFM). To "flat-spot" a cam lobe though ...seems like it would have had to of been knocking like hell for awhile to do that (like since before you bought it), so I would have thought it sounded bad when you test drove it at purchase time. Sounds like someone may have "over-reved/worked" the engine ...then traded it in when it started sounding shitty? Or ...the service senter could have made a small problem big when they tried to diognose the problem.

Regardless ...looks like you screwed (unless you bought an extended warranty at purchase time)??

And yeah, I turned off the AFM on my truck with my Diablo Sport Tuner ...because I paid for 8 cylinders!

"Electrical Lifters" huh?

They are hydraulically actuated and the hydraulics are controlled by a solenoid.

Yeah, like VMax2007 said ..."electronically controlled lifters".

An explanation from the "spec sheet": ...The final AFM component is the Lifter Oil Manifold Assembly (LOMA). This cast-aluminum assembly is installed in the Vortec 5.3's V, or valley, in place of a conventional engine block cover. The LOMA holds four solenoids, control wiring and cast-in oil passages. The solenoids are managed by the ECM, and each one controls oil flow to a De-Ac Lifter, activating and de-activating the valves at one cylinder as required for Active Fuel Management. The Gen IV Vortec 5.3L's fuel injectors are identical for all cylinders; those feeding the de-activated cylinders are simply shut down electrically by the ECM during de-activation. When the cylinders are deactivated, the engine effectively operates as a V4. AFM operation is load based, as measured by the ECM using dozens of inputs, overlain with the driver's demand for power as measured by throttle application. AFM's response time is measured in milliseconds. Operation is always transparent to the driver. The engine returns to V-8 mode the instant the controller determines that acceleration or load requires additional power.

alwcurlz · November 26, 2009

My 2009 Sierra has an "M Code" 5.3L engine. The "M" code denotes the "Aluminum Block/Aluminum Heads/Non-Flex Fuel" engine. They are not rare, and I haven't heard of this problem in the newer 5.3L (of any code). It doesn't seem impossible for a lifter to fail (especilly since that 5.3L has 4 electrical lifters in it for th AFM). To "flat-spot" a cam lobe though ...seems like it would have had to of been knocking like hell for awhile to do that (like since before you bought it), so I would have thought it sounded bad when you test drove it at purchase time. Sounds like someone may have "over-reved/worked" the engine ...then traded it in when it started sounding shitty? Or ...the service senter could have made a small problem big when they tried to diognose the problem.

Regardless ...looks like you screwed (unless you bought an extended warranty at purchase time)??

And yeah, I turned off the AFM on my truck with my Diablo Sport Tuner ...because I paid for 8 cylinders!

"Electrical Lifters" huh?

They are hydraulically actuated and the hydraulics are controlled by a solenoid.

Yeah, like VMax2007 said ..."electronically controlled lifters".

An explanation from the "spec sheet": ...The final AFM component is the Lifter Oil Manifold Assembly (LOMA). This cast-aluminum assembly is installed in the Vortec 5.3's V, or valley, in place of a conventional engine block cover. The LOMA holds four solenoids, control wiring and cast-in oil passages. The solenoids are managed by the ECM, and each one controls oil flow to a De-Ac Lifter, activating and de-activating the valves at one cylinder as required for Active Fuel Management. The Gen IV Vortec 5.3L's fuel injectors are identical for all cylinders; those feeding the de-activated cylinders are simply shut down electrically by the ECM during de-activation. When the cylinders are deactivated, the engine effectively operates as a V4. AFM operation is load based, as measured by the ECM using dozens of inputs, overlain with the driver's demand for power as measured by throttle application. AFM's response time is measured in milliseconds. Operation is always transparent to the driver. The engine returns to V-8 mode the instant the controller determines that acceleration or load requires additional power.

AFM sounds like a bad idea after reading that info. So, the system is just an oil flow control to the valves. The other thing that is transparent is the fuel economy from what I've read. It's the same fuel economy in V4 as in V8. In any event, I wonder if it is possible to replace the LOMA with an older generation block cover.

Nytemare · November 27, 2009

Absolutely nothing to do with this topic............

Jeff...I like your new sig man.

Nice "rear" shot.........WAIT....holy shit...your truck looks good too

VMax2007 · November 27, 2009

Absolutely nothing to do with this topic............

Jeff...I like your new sig man.

Nice "rear" shot.........WAIT....holy shit...your truck looks good too

It's not new, but thanks! It is my Holiday Sig.

AK FiveO · November 27, 2009

My 2009 Sierra has an "M Code" 5.3L engine. The "M" code denotes the "Aluminum Block/Aluminum Heads/Non-Flex Fuel" engine. They are not rare, and I haven't heard of this problem in the newer 5.3L (of any code). It doesn't seem impossible for a lifter to fail (especilly since that 5.3L has 4 electrical lifters in it for th AFM). To "flat-spot" a cam lobe though ...seems like it would have had to of been knocking like hell for awhile to do that (like since before you bought it), so I would have thought it sounded bad when you test drove it at purchase time. Sounds like someone may have "over-reved/worked" the engine ...then traded it in when it started sounding shitty? Or ...the service senter could have made a small problem big when they tried to diognose the problem.

Regardless ...looks like you screwed (unless you bought an extended warranty at purchase time)??

And yeah, I turned off the AFM on my truck with my Diablo Sport Tuner ...because I paid for 8 cylinders!

"Electrical Lifters" huh?

They are hydraulically actuated and the hydraulics are controlled by a solenoid.

Yeah, like VMax2007 said ..."electronically controlled lifters".

An explanation from the "spec sheet": ...The final AFM component is the Lifter Oil Manifold Assembly (LOMA). This cast-aluminum assembly is installed in the Vortec 5.3's V, or valley, in place of a conventional engine block cover. The LOMA holds four solenoids, control wiring and cast-in oil passages. The solenoids are managed by the ECM, and each one controls oil flow to a De-Ac Lifter, activating and de-activating the valves at one cylinder as required for Active Fuel Management. The Gen IV Vortec 5.3L's fuel injectors are identical for all cylinders; those feeding the de-activated cylinders are simply shut down electrically by the ECM during de-activation. When the cylinders are deactivated, the engine effectively operates as a V4. AFM operation is load based, as measured by the ECM using dozens of inputs, overlain with the driver's demand for power as measured by throttle application. AFM's response time is measured in milliseconds. Operation is always transparent to the driver. The engine returns to V-8 mode the instant the controller determines that acceleration or load requires additional power.

AFM sounds like a bad idea after reading that info. So, the system is just an oil flow control to the valves. The other thing that is transparent is the fuel economy from what I've read. It's the same fuel economy in V4 as in V8. In any event, I wonder if it is possible to replace the LOMA with an older generation block cover.

Oh, the AFM makes a difference on fuel mileage. More-so if yo do a lot of highway driving. I do about 30 miles round trip a day to work and back on the highway. When I turned AFM off with my Diablo Sport Tuner, I dropped a little over 1 mpg on fuel mileage. But, I prefere the way the truck runs when AFM is off.

Bye-the-way ...I like that "Holiday Signature" too!