I have finally made a believer out of my boss regarding UOA's.The water district I work at has had several engine failures because of coolant leaks.I sent in a UOA on one of our trucks and antifreeze was detected. Sent the truck to Chevy and they couldnt find a coolant leak.Well they changed the intake gasket per my order and they were non comittal about if that was it or not.Sent in another UOA and what do you know,no antifreeze,low wear numbers and low insolubles.Thank you Blackstone!