Overheating issue.
Our water pump went out and we replaced it. Kept over heating and going back to normal. Replace thermostat. Still had the problem of overheating and then going back to normal! Got to checking and radiator had a leak. Replaced radiator and it ran fine for about a half hour. Started overheating and going back to normal. Out of ideas as to what it could be. Any ideas as to why the gauge would go to red then back to normal and back up again?