Is Your Gmt-900 Truck Or Suv Using Oil

Volcom26 · March 15, 2011

There are many topics out there and no real data between members. Hopefully this will catch some data and show a real story. Please be thruthful with your selections.

Please only post oil consumtion concerns here and please stay on topic. Please no long debates about AFM people either love it or hate it we all understand this.

Thanks!

2007 NBS Silverado 1500 z71 with 5.3 AFM (22,000 miles) tow's hard through Cajon/Baker grade(pulling 7k), many mountain trips...

NOT using/burning any oil(mobil 1 from the start, now switching to Amsoil) 5w30 always...

Truck see's extended freeway towing w/rpms between 3-5k...

FYI my Honda Prelude (H22 Vtec) uses at least 1qt per 3000k... Wanna know what Honda thinks? "normal" :-)

Edited March 15, 2011 by Volcom26

hodo78 · March 15, 2011

2010 6.2L, No AFM of course. (I believe all 6.2 are aluminum, correct?)

Currently 13,400 miles

Mobile 1 5w30 & Mobile 1 filter every 5,000 miles

NO Leaks.

2007 5.3L AFM, Iron block.

Mobile 1 5w30 & Mobile 1 filter every 5,000 miles

Traded at ~40,000 miles

No Leaks up until or at trade in.

Volcom26 · March 18, 2011

Upon further investigation of AFM system GM uses in the 5.3/6.0 I have come to a conclusion about why some trucks can consume more oil than say a normal ls1 motor...

These new GMT-900's use a system called the "Valve Lifter Oil Manifold" (VLOM) basically it controls the Lifters & Cylinder de-actavtion process by using "oil pressure" to activate & de-active the lifters/valves & certain actions in the manifold, along with PCM cutting injectors & only runs on 1,4,6,7 which also change to a cam lift of .289 (instead of other 4 cyl at .283)

This is a beautiful design & impressive when you really understand/comprehend it's complexity yet solid work this system handles... It delivers High output with MPG!!

This is very important to understand & due to the extreme abuse this puts on the oil(not including the normal oil duties) and it is very similar to Varaible Valve timing applications like the VVT & Vtec type engines used for 20 years in Imports like Honda/Nissan...

With that in mind, "all types" of these engines that have an "oil controlled" variable valve modifying system are all "normal" users of oils...

"" Up to 2qts between oil changes!""

This is considered normal, Now this by no means is a perfect system but very beneficial to modern HP and MPG expectations!

We all want more of both right? :-)

Now here's the tricky part, some people are drinking oil & it's way more than normal... That may be a faulty motor build or maybe poor quality oil, or even worn rings/valve guides... There are many variables that GM has no control over! But If GM messed up on your ride make them fix it do the "consumption test" so they can prove the engine Does or Does NOT fall in between the "normal functions for type of motor"

So again in short, I don't burn oil in my 5.3(22k miles) but I may very well or may not... The design of the motor does put me in the "up to 2qt is normal" bracket but guess what?

For the balance of HP/MPG I pull out of my finely tuned z71 (almost 26 mpg on the highway!!) I can live with it because I understand the technology... Plus geuss what I stomp that pedel down & I have almost 300whp to move me along quite swiftly when I dont want MPG.... Its the Best of both worlds!

I have more to add & will fix the typo's (I'm on my IPhone)

All I want is to Stimulate some useful posts & share the facts about GM Trucks with everyone instead of just reading posts like "my truck burns oil I hate GM for that" or " i paid xxxxxx and it uses oil...." Please people lets get some useful, informative INFO on here!!

You know? :-)

Edited March 18, 2011 by Volcom26

441G · March 18, 2011

my last 2 trucks - 2005 5.3 2wd 18mpg city 20 highway, the truck i have now 2007 5.3 afm 2wd oil burner 17mpg city 17 highway. they both had the same power.

seamonster · March 20, 2011

I have a 09 GMC 6.0l and change the oil when the monitor tells me to, usually about 5000-6000 miles. I always check the dipstick after oil is changed and before I bring it back in and the level usually about 1/4 to 1/2 quart low. Not bad for 5000+ miles.

You never mentioned your mileage on the truck. Oil consumption usually starts at 30,000+ miles. Do the 6.0's have AFM?

My 6.0 in my 07 1500 vortec Max has AFM and does not use oil but I only have 11K on it.

hillbilly4u · March 20, 2011

There are many topics out there and no real data between members. Hopefully this will catch some data and show a real story. Please be thruthful with your selections.

Please only post oil consumtion concerns here and please stay on topic. Please no long debates about AFM people either love it or hate it we all understand this.

Thanks!

2007 NBS Silverado 1500 z71 with 5.3 AFM (22,000 miles) tow's hard through Cajon/Baker grade(pulling 7k), many mountain trips...

NOT using/burning any oil(mobil 1 from the start, now switching to Amsoil) 5w30 always...

Truck see's extended freeway towing w/rpms between 3-5k...

FYI my Honda Prelude (H22 Vtec) uses at least 1qt per 3000k... Wanna know what Honda thinks? "normal" :-)

Why post if you're not using oil, but please vote. The purpose of the poll is to get some data on who, and how many, are using oil and how much per 3k.

Volcom26 · March 20, 2011

QUOTE (Volcom26 @ Mar 14 2011, 10:23 PM)

QUOTE (RyanbabZ71 @ Feb 19 2011, 06:22 AM)

There are many topics out there and no real data between members. Hopefully this will catch some data and show a real story. Please be thruthful with your selections.

Please only post oil consumtion concerns here and please stay on topic. Please no long debates about AFM people either love it or hate it we all understand this.

Thanks!

2007 NBS Silverado 1500 z71 with 5.3 AFM (22,000 miles) tow's hard through Cajon/Baker grade(pulling 7k), many mountain trips...

NOT using/burning any oil(mobil 1 from the start, now switching to Amsoil) 5w30 always...

Truck see's extended freeway towing w/rpms between 3-5k...

FYI my Honda Prelude (H22 Vtec) uses at least 1qt per 3000k... Wanna know what Honda thinks? "normal" :-)

-------

Why post if you're not using oil, but please vote. The purpose of the poll is to get some data on who, and how many, are using oil and how much per 3k.

--------

If you look a couple post's later you will see why I posted on this fourm & and the oil consumption thread, and no offense but I would like to hear you explaination on why some trucks are using oil? Or is your helpful input on this thread asking me why I post?

Geez my man, I don't give enough useful info or imput? I would like to see more facts, information & data sharing, not calling out why I am trying to help & impart knownledge to the masses... Especially for those that truly don't understand the tech... Thanks alot buddy!

Edited March 20, 2011 by Volcom26

Gup1 · March 20, 2011

I have a 2007 Yukon XL with 5.3. Low oil light came on for the first time between oil changes at around 85,000. Tech determined that filter was loose and leaking which is was so no real concern at that point, oil was changed. Low oil light came on again around 88,000 miles. No loose filter this time. Added a quart to get to the next oil change at 89,000 miles. Watched the oil consumption closely and it is using about a quart per thousand miles. After researching the oil consumption issue and GM's effort (lack of) to correct I ordered a Ford F-150 EcoBoost crewcab pickup at a Ford/GMC dealer. It is still under powertrain warranty so GM can fix it if they want but I am not going to mess with it any longer. I would not consider another GM product after they paid themselves the big bonuses while still owing the taxpayer for their bailout. Sorry for the politics but it affected my buying decision.

ffthornton · March 23, 2011

My truck is a 2008 GMC sierra with 5.3 and AFM. Did not have an issue until I swapped oils that I was using. I have been using royal purple and swapped to Mobil one because it was a little cheaper. After a little whiule I notice a little puff of smoke on cold start up. Now I have about 25% left before next oil change and noticed the lifter tapping after gassing it going down the road. Also noticed going down the road the oil pressure would bottomed out and jump to 40 psi. That is when I noticed it was low on oil.

My truck was tuned with about 14000 miles on it and AFM turned off. Now it has almost 33000 miles on it. I think it is the oil but it could be coincident.

mtiffinal · March 24, 2011

At 3000 miles past the repair noted on page 1 of this thread, 3/4 quart low.

browning22 · March 25, 2011

I hope the following helps everybody out. This is a list of things that I have done that obviously did not work for me and the one thing that has shown promise so far.

Oil Guzzling Test- 2 qts / 2000 miles

Severe smoking at startup.

Installed deflector shield per TSB - Had no effect on vehicle except maybe lost a few mpg. This has not worked for anyone I know.

Predator Diablo - Disabled AFM, had no effect on oil consumption or smoke.

Engine Flush - Completely cleaned carbon out of engine. Helped with smoke for two days. Smoke has returned.

I recently bought some AT-205 oil additive and went directly to have my oil changed and mixed it in with the oil. After driving 1000 miles I have not consumed any oil and my smoking is gone.

I know this may not be a permanent fix, but what this tells me is I've got valve seal problems. I have a friend who is working on his 6mos of driving and the issue has not returned. Hope this helps some of you.

71zedder · March 27, 2011

2007 sierra z71 crew cab. LH6 motor aluminum block with AFM. 63000kms. Bought used last summer and in less than 3000kms the add engine oil light came on. Not impressed. No smoke anytime. Been on oil consumption list at dealer since last Sept(2010). Dealer says 1liter in 3200kms is acceptable to GM. But not to me.

Here are my numbers. 0.8liters in 2633kms, 0.8liters in 1588kms, 0.35liters in 991kms, 0.5liters in 764kms, oil change when service life reached 5% (guess all it needed was a filter LOL oil already changed), then 1.2liters in 755kms- (not sure what the story is here its a bit high). At cold start up I have slight lifter tap or piston slap.

Mostly driving to work on rural roads so AFM is on a lot. But, seems worse when i'm idling in cold weather to warm up. No AFM when idling so can't say its related but since discussing this with other GM truck owners with 5.3l, some with no afm, seems like most are using a little oil, around a liter between changes.

GM can't really expect people to swallow that this is normal, even at 1 liter/3200kms. It's going somewhere and will cause problems later, either sludge or killed catalytic converters etc.. Have been loyal to GM for 20 years but my next purchase will depend on how this is handled.

Edited March 27, 2011 by 71zedder

Volcom26 · March 27, 2011

I hope the following helps everybody out. This is a list of things that I have done that obviously did not work for me and the one thing that has shown promise so far.

Oil Guzzling Test- 2 qts / 2000 miles

Severe smoking at startup.

Installed deflector shield per TSB - Had no effect on vehicle except maybe lost a few mpg. This has not worked for anyone I know.

Predator Diablo - Disabled AFM, had no effect on oil consumption or smoke.

Engine Flush - Completely cleaned carbon out of engine. Helped with smoke for two days. Smoke has returned.

I recently bought some AT-205 oil additive and went directly to have my oil changed and mixed it in with the oil. After driving 1000 miles I have not consumed any oil and my smoking is gone.

I know this may not be a permanent fix, but what this tells me is I've got valve seal problems. I have a friend who is working on his 6mos of driving and the issue has not returned. Hope this helps some of you.

Very useful info, remember that a "thicker" oil does have a harder time making it through rings/valves also can slow down gasket leaks as well... Not a complete fix but can help limp the problem along for many miles! (I know of people using straight 30 weight oil in summer and as high as 20-50w in winter to slow down leaks!) it all depends on how extreme the weather you drive in & how bad the leak/consumption is... And 10-w40 is a realitivly safe "thicker" oil wieght especially in say southern cailfornia & on you higher mileage rig's out there... (50-60k & above)

Everyone remember to check for leaks on the engine pan & rear main seal! There are TBS out about different gaskets types that cause oil pan leaks(metal gasket vs rubber gasket) some can even have a faulty pan that will leak only under "driving" conditions, which leaves NO oil puddle in your driveway, BUT still leaking between the engine/trans area as you drive! I had a similar problem years ago... Would not trip the oil light, but would be just a lil low during drain intervals...

Some could be suffering from one or all three of the major oil problems found on some of the gtm-900 (AFM normal oil abuse/poor oil quality, faulty or worn rings/lifters/valve guides, or lastly oil pan/rear main oil leaks) any one of those can account for oil loss & if suffering from all three?!? that would drink a whole lot of oil for sure...

Lastly, for all of you out there that wait till your idoit light comes on &/or hearing lifters tapping or oil pressure spikes to 0.... Holy crap people!! Check your oil at every gas tank fill up or at least every 500 miles...

"Everytime you run your engine that low on oil YOU are doing more & more damge!!!"

Edited March 27, 2011 by Volcom26

SuDoNum · March 31, 2011

2007 5.3 Cast Iron with AFM. Around 50k miles. Average approximately 5000 between changes. Changed the oil around 40k miles, added one quart before the next change. The same thing happened after the next change. 1000 miles after my most recent change it needed a quart, added another quart today, after about a 1000 more miles. Information center says oil is currently at 55%. At this rate I'll use 3-4 quarts between changes, 10,000 miles ago it was zero. Taking it to the dealer as soon as I can.