Time to check for a head gasket leak or a cracked head- - - -water pressure, air pressure, or a "block test kit" which uses an indicator liquid to detect combustion gases in the cooling system.
The test fluid sold by NAPA seems to work better than the supposedly same stuff sourced elsewhere, even O'Reilly's.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!