Why would a 1997 Ford Windstar temp gauge reach the H while setting idle but go down in drive and when you rev the engine go back to normal?

Answer 1

Answer

prob low on coolant. More then likely though you need to flush the radiator. Because when you rev the system fan forces air into system and cools vehicle somewhat check coolant had this same problem from a leak in my water pump at freeway speeds and being a cool day ran great but during idle almost immediate overheating

3 more things to check

• Engine cooling fans are working - fuses, are plugged in, relays working
  
  

• Radiator / cooling system flush - to be honest, I'd suggest having it professionally done. Find a Fall special at a local repair shop
  
  
• Water pump - the water pump 'impeller' can wear or come loose from the shaft

See "Related Questions" below for more
Answeralso check for automatic idle adjustment. this sort of works like a choke allowing engine to idle up or down when needed this is especially needed if using a/c as a/c makes engine work harder needing more cooling, such as coolant flow and air from outside engine compartment