2015 Chevy 1500, 5.3 Oil overflowing coolant tank. No water in oil.
Checked oil cooler in radiator both with 20 psi of air and 22.5 inches of vacuum. No evidence of leak.
Old school, so I pulled the left head, then realized this motor has no high oil pressure anywhere near a water jacket at the heads.
Any other ideas??? Or should I pull the trigger and blame the block?