truck is loosing coolant but no smoke from tailpipe and no bad smell in engine on 1992 Chevrolet 1500 Pickup

started having low coolant issues and inc. temps, shop said water pump needed replacing, within a week low coolant light was on again, this time they said reservoir was cracked, again within a week the low coolant light started coming on and temps start going up if I don't add coolant every couple of days. no smoke coming from tailpipe and engine doesn't smell bad, however no coolant appears to be leaking on the drive where truck is parked. everyone says it's probably the head gaskets but I everything i read indicates there'd be smoke from tailpipe and smell - what else can be happening with the coolant?

It's either leaking or the engine is consuming it!!!.... One or the other..... Have the system pressure tested for any leak(s). ...... Have a combustion leak test performed to confirm no head/gasket issue!!... Intake manifold isn't leaking coolant into the engine oil is it?