Hey everybody, I have a 2011 Chevy 2500HD with the 6.0 Vortec, 285k miles. It runs great, no issues whatsoever. A friend was recommending I do a custom tune on it that would get better mpg. Not sure if that’s a good idea on a high mileage motor.

And thinking about the tune got me wondering about switching to all synthetic oil. It’s been 5W-30 its entire life.

Thoughts?

PM GassGuzzler, sir

I got 12.5 mpg when I bought mine in 2001 and I still get 12.5 today. Amazing.

imo, don't 'fix' it - if it ain't broke!
Got 358K on a 2005 6.0 Vortec in my 3500, and it's still running strong.
First 100k she got plain ol penzoil standard 5w30 and fram filter every 3k miles.
Ever since then I've been putting Walmart Super-Tech 5w30 Full Synthetic and a Fram Ultra filter every 'computer light' oil-change (about 7500miles).
She doesn't burn a drop of oil between changes!

I'm with oldoak. If it ain't broke, don't fix it. It doesn't sound broke to me. I'd keep doing what you've been doing.

My 2011 5.3 has had the 4 cyl delete for fuel milage since around 150k. It hasnt helped but it has not hurt it. I would just run it. I ran synthetic till about 150k and switched it to rotella T 15w40. It might not be right but it still works

I know where there is a 2004 5.3 that’s surpassed 600,000 miles. He had to replace the camshaft at about 550,000.

Only thing i would is prior to the next oil change add 1/2 can of Sea Foam to crank case. Run it another 100 miles then change the oil. It will get any sludge out.
Other than that, as said don't fix what isn't broke.

Leave it alone.

I have a 2003 6.0L and a 2007 5.3L with tunes.The 6.0L is in a Yukon Denali and my wife averages about 12 MPG, all stop and go. My Sierra 2WD averages 9.0 MPG, all stop and go. The 6.0L will get 16 on the highway and the 5.3L will get almost 20. They both have over 180K miles. The Yukon has an OEM electric can conversion that required the tune anyway. The Sierra was tuned for MPG when my Dad owned it before me. Drive-ability is better on both, especially with electric throttles...but in no way is it worth the cost for MPG. 2500 doesn't have Active Fuel Management so saving the camshaft isn't in the cards. Your 4L80E transmission has no real tuning problems. Save your money and plan on an oil pump one day. Had a guy bring his similar truck all the way from Farmers Branch for a "maintenance oil pump" at 485,000 miles.