Hi I have 2013 chevy tahoe ppv and was wondering can I trust the oil life monitor? Most of my local mechanics say hell no change it every 3k miles. But mechanics on the internet say you can trust it sighting long papers on how it works and how advanced it is. I figured scotty is a good honest trustworthy mechanic, what are your thoughts on the OLM on the gm vehicles? My tahoe turned the change oil soon message on after about 10k miles after last change. Keep in mind I do about 80% highway driving.
I would not trust those systems. Change the oil and filter every 5k miles/once a year.
I don't trust any of those systems from any car manufacturer. On older cars when tolerances weren't that good 3k was a good rule of thumb. It's a good idea to be checking the dipstick at least monthly. That way you can see the condition of your oil by the color, and judge when you need to change it. We've got a Chevy truck and 2 Toyota products and change the oil at 5k miles/ 6 months.
3k is overkill
The oil life monitor on my 2013 is pretty accurate actually. I verify it with my own readings of course, and I monitor the oil condition for water or fuel contamination, but it is pretty reliable.
If what Scotty says is true, and highway driving equates to 10% of city driving, then
your 80% x 10,000 miles = 8,000 highway miles
x 10% = 800 city miles.
The engines in those Tahoes (5.3?) are pretty robust. Your biggest concern is going to be the AFM system (if equipped)
hmm ... so nobody questions the 10% thing?
If Scotty is correct, then you only need to change your oil every 50,000 miles if you only drive on the highway.
In Scotty's defense, I think he means 10% ware and tare on the vehicle with highway miles but only if scheduled maintenance is done. 
Been discussed before: see below.
https://carkiller.com/scottykilmer/qa/oil-change-18/#post-183730
https://carkiller.com/scottykilmer/qa/when-should-i-change-my-oil/#post-99445
1 year/5k miles. Whichever comes first. That's your best bet using full synthetic, any brand.
