Chevrolet Repair: Liquid sloshing, coolant level, head gasket

Question
8 cyl 1989 1500 Chevy pickup can hear liquid sloshing. Sounds like just beyond fire wall.  It seems to be recycling through the engine. Husband said probably coolant.  Have had repairs to the head gasket.  Could this had caused it.  Can it be repaired or can this be causing any damage? We hear it when driving and when stopping and starting to roll.  Been doing it for about 9 years but no one has any answers. Water pump and thermostat has been replaced. Have run wire up through the ac drain but no water comes out there.  Is water trapped somewhere?127,000 miles and original radiator and heating coil.

Answer
hmm, check coolant level and then if that is ok check for excess water in the body frame parts under the windshield wipers. i had water collect there once. but if its been doing it for 9 years and the things still runns it may not be as big an issue as you think. have ya replaced the heater core itself? could be many things. but im all out of answers.... let me know if you ever find out what caused it.