Some 2012 Cadillac Escalade, Chevy Avalanche/Silverado/Suburban/Tahoe, GMC Sierra/Yukon/Denali vehicles may experience a coolant leak. The cause may be traced to an ill-fitting coolant overflow tank nipple.
The leak is caused by excess plastic at the parting seam on the tank nipple, preventing proper hose sealing.
The repair involves sanding the plastic seam on the nipple to create a more uniform sealing surface for the hose. Do not replace the overflow tank, since sanding the seam will fix the problem; and the replacement tank might have the same excess plastic on the nipple.