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Username Post: 2009 Suburban Oil Usage        (Topic#353147)
black95jimmy 
"11th Year" Silver Supporting Member
Posts: 9284
black95jimmy
Age: 74
Loc: Venice, FL
Reg: 01-05-02
09-23-18 07:40 AM - Post#2746971    

Just returned from a 7000 mile trip, up the East coast, over to Michigan, Chicago, Rapid City and return. Used a quart of oil every 600 miles!!

Looked it up on internet, said replace the drivers side valve cover, better baffling.

Anyone else done this? Did it help?

82 Monte Carlo SC, 355 w/Vortec heads, roller rockers, 670 Street Avenger, TRUE DUALS.
2009 Sub.5.3L LTZ 30 Gallons of gas @ $2.49/gal. bla bla bla.


 
elcamino 
Dedicated Member
Posts: 5363
elcamino
Loc: Lake Superior-Michigan US...
Reg: 03-30-00
09-24-18 03:09 AM - Post#2747046    
    In response to black95jimmy

This is just one of the many bulletins they put out on oil use for 2007-13 AFM engines. Typically with oil consumption like you mentioned, its too late as the piston(s) looks like the one below and the only solution is new pistons and rings; provided the cylinders are not damaged.
  • Quote:
Oil Use in 5.3L AFM engines

This condition may be caused by two conditions. Oil pulled through the PCV system or oil spray that is discharged from the AFM pressure relief valve within the crankcase.

Under most driving conditions and drive cycles, the discharged oil does not cause a problem. Under certain drive cycles (extended high engine speed operation), in combination with parts at the high end of their tolerance specification, the oil spray quantity may be more than usual, resulting in excessive deposit formation in the piston ring grooves, causing increased oil consumption and cracked or fouled spark plugs (#1 and/or #7). Refer to the latest version of Corporate Bulletin Number 120601001




Carbon buildup on pistons can cause the piston rings to stick in their grooves. Stuck rings can fail to seal the combustion chamber, leading to oil consumption and low compression, negatively affecting engine performance. Excess piston deposits can also lead to pre-ignition (pinging) and engine knocking, which results in lost power, reduced fuel economy and, in severe cases, engine damage. GM came out with new tougher dexos oil specifications in circa 2013 to combat this problem. It basically required oils to have lower volatility rates, aka less evaporation.

This is what the piston in the affected cylinder(s) can look like in extreme cases.


Circa 2013 GM came out with tougher oil specifications (dexos) to try to reduce oil consumption. Basically dexos lowered the acceptable volatility rate (evaporation) of engine oils from 15% to 13% max., among other improvements in oil quality.

Mike
2017 GMC Sierra Denali Ultimate 6.2L(420hp)/8-sp Z95
2018 Polaris RZR S 900 EPS


 
black95jimmy 
"11th Year" Silver Supporting Member
Posts: 9284
black95jimmy
Age: 74
Loc: Venice, FL
Reg: 01-05-02
09-24-18 06:06 AM - Post#2747055    
    In response to elcamino

UGH!!!

82 Monte Carlo SC, 355 w/Vortec heads, roller rockers, 670 Street Avenger, TRUE DUALS.
2009 Sub.5.3L LTZ 30 Gallons of gas @ $2.49/gal. bla bla bla.


 
black95jimmy 
"11th Year" Silver Supporting Member
Posts: 9284
black95jimmy
Age: 74
Loc: Venice, FL
Reg: 01-05-02
09-24-18 10:49 AM - Post#2747072    
    In response to black95jimmy

What is wrong with GM that they cannot test an engine under normal driving conditions so that these things don't happen? Before AFM, these trucks would last forever.

So, looks like I need a new short block. Nice.



82 Monte Carlo SC, 355 w/Vortec heads, roller rockers, 670 Street Avenger, TRUE DUALS.
2009 Sub.5.3L LTZ 30 Gallons of gas @ $2.49/gal. bla bla bla.


 
elcamino 
Dedicated Member
Posts: 5363
elcamino
Loc: Lake Superior-Michigan US...
Reg: 03-30-00
09-24-18 03:39 PM - Post#2747101    
    In response to black95jimmy

Fuel economy is all they are thinking about. Some consolation is that 2015+ GM engines are a different breed. My neighbor has a 2015 Silverado with 120,000 miles and he said it only uses about 1/2 qt between changes and he goes by the oil life monitor because that's all his employer will reimburse him for. He is allowed to buy a new vehicle every 3 yrs.

Where AFM always shut down the same 4 cly, new 2019 engines have dynamic fuel management where it shuts down up to 7 cylinders at one time in random order so all 8 get cycled on/off as power demands dictate. The weakness in the AFM system is that its always the same 4 cyls and those seem to be the ones with the oil use problems.

Not to worry, the ecoboost has its own share of problems.

Mike
2017 GMC Sierra Denali Ultimate 6.2L(420hp)/8-sp Z95
2018 Polaris RZR S 900 EPS


 
wreckmech 
Member
Posts: 212

Loc: Parsippany, NJ
Reg: 10-08-02
09-25-18 08:02 AM - Post#2747148    
    In response to elcamino

I bought my 2014 GMC with 65,000 on it and the first thing I did was buy a tuner to deactivate the AFM. Knock on wood, so far I'm doing ok. I'm up to 90,000 with no issues.

When it goes, I'm going to do the AFM delete kit with new cam & lifters....



 
black95jimmy 
"11th Year" Silver Supporting Member
Posts: 9284
black95jimmy
Age: 74
Loc: Venice, FL
Reg: 01-05-02
09-29-18 07:07 AM - Post#2747466    
    In response to elcamino

I'll start with a $70.00 valve cover, see what happens.

82 Monte Carlo SC, 355 w/Vortec heads, roller rockers, 670 Street Avenger, TRUE DUALS.
2009 Sub.5.3L LTZ 30 Gallons of gas @ $2.49/gal. bla bla bla.


 
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