what causes oil gauge fluxuation on 08 dodge ram 1500 4.7 flex
I recently replaced water pump, thermostat, belt, fan clutch and coolant. 1st test drive engine ran too hot. Checked coolant added I/2 gal. ran seemed ok. Next day made 15 mile trip last mile temp gauge pegged check gauge light came on. Stopped and checked engine didn't seem to be hot added another 1/2 gal. coolant gauge back to normal. Monday drove to work & back 30 miles all is well. On Tuesday drove back to work and on the way home all is well until I turned into driveway and stopped now oil gauge dropped to zero check light came on revved engine oil pressure came back up but dropped at idle again. What could be going on here?