2004 Tahoe w/114000 miles puffs blue smoke at start up. Chevy dealer did diagnosis on compression and breather w/nothing showing up as being bad. Oil consumption is now 1 pint to 400 miles since this started. No consumption before. What could be wrong?
Smoke at start-up usually points to leaking valve guide seals. A compression test won’t reveal leaking valve guide seals.
What you might try at this point is on the next oil change, is switch to high mileage oil such as Valvoline Max-Life and see if this reduces the smoke at start-up. If it does, then it’s probably the valve guide seals leaking. So you make the decision if you want to continue to use an oil that reduces oil consumption? Or pay to have the valve guide seals replaced?