Is Your Gmt-900 Truck Or Suv Using Oil

[jagabom (Esquire)]

On 12/18/2017 at 5:07 PM, Service1956 said:

I think the best a person can do is eliminate the 6000-7000 mile synthetic oil changes that some do because they believe that synthetic oil last longer than the petroleum based products. The problem is, is that letting it go that long contributes to the problem of too many hydrocarbons building up in the crankcase and mixing with the oil therefore contaminating the oil in reducing lubrication and speeding engine wear. I could be wrong, but that's my theory.

Agree there.  100%

Jim

2011 5.3 Sierra

[BlazinDonkeys]

01 Silverado 4x4 used about 2 qts every 3k miles. Rebuild on the 5.3 at 247000 miles with new rings, valve seals, bearings, cam and tune......still uses 2 qts per 3k miles. I rebuilt because it had 3 broken lifters, still ran fine except for the occasional miss at idle.Most of my driving is 80mph+. I feather it off the line, no hard acceleration. After the cam swap I'll chirp the tires (rarely...?)on 2nd gear, love the noise it makes now. Like an ex nascar truck?

[bg1988]

On 2/19/2011 at 5:22 AM, RyanbabZ71 said:

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 truthful with your selections.

 

Please only post oil consumption 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!

Build Date 01/2008 Model Year 2008

No oil consumption  2950 miles into the oil change..   (I plan to change it at 3200-3400 miles) 

No Sludge 

6.0L with AFM & VVT (Hybrid Vortec  6000   379HP/472ft-lb torque)

AFM Enabled 

89,497 miles with 1380.2 Engine ON Hours  Average speed 65MPH  

No Sludge 

OIl used Mobil1 Full synthetic SN/SN Plus

Mobil1 filter

OIL PSI cold start 70-75PSI

OIL PSI    45PSI hot

 

 

 

  I rather get great MPG with the AFM     my typical combined is 25MPG

 

Typical City is 22.5MPG 

Typical Highway MPG is 32MPG  

 

better then TOYOTA  Camry 4 cyl, 2.4 L 2008)

Edited July 2, 2019 by bg1988

[Pinnacle]

46 minutes ago, bg1988 said:

Build Date 01/2008 Model Year 2008

No oil consumption  2950 miles into the oil change..   (I plan to change it at 3200-3400 miles) 

No Sludge 

6.0L with AFM & VVT (Hybrid Vortec  6000   379HP/472ft-lb torque)

AFM Enabled 

89,497 miles with 1380.2 Engine ON Hours  Average speed 65MPH  

No Sludge 

OIl used Mobil1 Full synthetic SN/SN Plus

Mobil1 filter

OIL PSI cold start 70-75PSI

OIL PSI    45PSI hot

 

 

 

  I rather get great MPG with the AFM     my typical combined is 25MPG

 

Typical City is 22.5MPG 

Typical Highway MPG is 32MPG  

 

better then TOYOTA  Camry 4 cyl, 2.4 L 2008)

This some type of joke? I heard of the Hybrid reaching 18 in city but never that. my AFM 6L at best gets 14 city 

 

[Jsdirt]

I hear that, Pinnacle. I've got the same truck, a model year older. One time I got 19 MPG out of my Silverado (with the AFM disabled by a Range device) on a cross-country trip from MA to CA. Best I've ever seen, but was also running WY fuel - probably alot less ethanol than in MA.

 

When the truck was new, after break-in, best I ever saw was 18 ... then it dropped to 16, and stayed there for several years. Now I'm at 13-14, with 97k on the clock. Probably the crap injectors (among the rest of the crap) GM grabbed the low-bid on.

 

EDIT: Ahh, missed the hybrid part. Still, those numbers are fantasy land.

 

On top of that, good luck finding parts for that engine WHEN it fails.

Edited July 2, 2019 by Jsdirt

[bg1988]

52 minutes ago, Pinnacle said:

This some type of joke? I heard of the Hybrid reaching 18 in city but never that. my AFM 6L at best gets 14 city 

 

Hypermiling with the most optimal route possible     (including tailgating 18wheelers with in 200ft )

over the last 500 miles i averaged 24.5  combined 

last 160 miles was 28.5MPG combined.. (different route with slight grade compared to previous route)

Using Power Regeneration Hack  

 

Not really hard to find parts it's LS2 based engine block. aluminum .Cylinder Head Casting Number 799 or 243..... and the rest of the components are  off the shelf  (Same High voltage Cells as toyota Prius battery) 

 

 

the only issue would be the transmission

 

But i expect this Allison Transmission to last 300,000 miles

 

this is a $10,000  transmission  not a cheap $3500 one..

Edited July 2, 2019 by bg1988

[Jsdirt]

I know of one that got scrapped due to unobtanium parts - can't recall the details, but it was something hybrid specific that GM engineered into that setup. Might have been CAN bus, module, or harness related.

 

Hope you keep it garaged ...

[bg1988]

3 minutes ago, Jsdirt said:

I know of one that got scrapped due to unobtanium parts - can't recall the details, but it was something hybrid specific that GM engineered into that setup. Might have been CAN bus, module, or harness related.

 

Hope you keep it garaged ...

I drive it gently ...  parts are plentiful in California 

[Jsdirt]

 Alrighty then. Good luck. 

[bg1988]

6 hours ago, Jsdirt said:

 Alrighty then. Good luck. 

well it does Stay in V4 mode =  80MPH =  1900RPM  that is the top speed i have seen v4 Mode  With 3.08 ratio

 

I don't think it will do above 2k rpm with V4 mode(have not tried)

it's configured for using the AFM as much as possible  that is why they did not put a 3.9L ,4.2L v6, 4.8L or 5.3L  because they are weak links...  AFM is useless in those engines.....

 

AFM really can save fuel with the eAssist  duo 80HP motors...

 

there is a glitch hack that allows the battery to recharge while  accelerating at the same time with v4 mode = fuel savings

 it's the undisclosed  3rd Mode 

 

 

 

 if it stays in v8 mode only my mpg drops to 16.5 city  18 highway.  it has done this with crappy fuels  even top tier fuels.

...

Edited July 2, 2019 by bg1988

[Cowpie]

On 7/1/2019 at 8:21 PM, bg1988 said:

Hypermiling with the most optimal route possible     (including tailgating 18wheelers with in 200ft )

over the last 500 miles i averaged 24.5  combined 

last 160 miles was 28.5MPG combined.. (different route with slight grade compared to previous route)

Using Power Regeneration Hack  

 

Not really hard to find parts it's LS2 based engine block. aluminum .Cylinder Head Casting Number 799 or 243..... and the rest of the components are  off the shelf  (Same High voltage Cells as toyota Prius battery) 

 

 

the only issue would be the transmission

 

But i expect this Allison Transmission to last 300,000 miles

 

this is a $10,000  transmission  not a cheap $3500 one..

If maintained properly and used properly, the Allison should go a lot longer than that.  

[Jsdirt]

Put power through them, and they fail before 200k. Limp-mode city.

[bg1988]

On 7/3/2019 at 7:18 AM, Jsdirt said:

Put power through them, and they fail before 200k. Limp-mode city.

 I keep under 80mph 1900rpm(4 banger mode)  accelerating slowly obviously 

I don't think AFM puts much of a heavy load..

 

 yes it is well taken care of  I don't do burn outs  ..  and keep under 2k rpm(occasionally might go over if necessary to prevent getting rear ended etc  or CA-110  stop SIGN entrance )  I don't tow.  Transmission temp is keep about 157 to 165F...

 

If i want or feel like abusing a car I'll rent a car.

 

 

gotta break in the new engine/transmission  with burn outs and HIGH revving the engine....

 

 

if i Do  rent one i'm putting 1,000 miles in a day or so gotta get my moneys worth...

going at lest 110-120mph

 

Edited July 4, 2019 by bg1988

[Dnt]

2009 Hybrid Tahoe 209k  has averaged 18.5 over the last 2500 miles real world driving no hypermilling mix of city and highway driving. HOWEVER it has a 3.5" lift and oversize wheels and Tires (Nitto grapplers)  Uses around 2 gts oil every 3k miles. My driving style is aggressive at times with WOT and some tire chirping LOL that seems to bring the mpg down and make for some oil blow through. The Old beast runs and drives dang good....

[Cowpie]

Still, 2 qts in 2500 miles is pretty sad.  The factory remanned Detroit crate engine in my heavy truck now has about 991,000 miles on the engine and it only uses about 2 qts of oil in 22,000 miles.  Changed the oil over 13,000 miles ago and the oil level is just now starting to come down off the full mark on the stick which indicates it has used just about a quart.  It is a 1 gallon increment between Add and Full on the stick.

Edited July 7, 2019 by Cowpie