Temature keeps climing gradually as I drive.have new water pump.I bypassed the heater.what causes it to heat up?

Keeps climing, stays cool, then just gradually climbs up, and doesn't drop back down, sounds like the thermostat has gone bad, they are actually very cheap to replace.

No thermostat in it

It should have one... oh well, look for collapsed hoses, and also, whens the last time it had a good flush? May have a blockage... also it may have too much antifreeze to water ratio, the water is what actually cools it, antifreeze keeps it from freezing.