2000 blazer valve tick

my wifes blazer has an almost constant tick. the oil pressure is great, oil is full . have the oil changed every 3000 mi and yet the tickng will not stop. drives me nuts. not real keen onthe idea of a fluch unless it is REALY ness.
any help would be greatly appreciated. thanks in advance.
P.s. 125k on the motor

Get a can of Seafoam motor tune. Dump half the can in the oil. Start it up and let run until the noise stops. Change the oil. Dump the other half in the new oil, in the gas tank, or hang on to it for another day. If its the hydraulic lifter causing the noise the Seafoam has never let me down! If it doesn't go away you may have bigger problems.

The seafoam worked great! worked within 20 Minutes ....no more ticking ...yeah. THANK YOU no more ticking. Something else to add to the mental library of knowledge
Thank you again.

Miracle in a can!