Windstar 98, herratic idling

Water pump fins are worn . Not moving enough coolant at idle .

that could mean that your water pump impeller is broken. when you press the gas the remaining piece of the impeller is pushing the water and it actually makes it to the heater core. at idle it isn't spinning fast enough. ask a local autoparts store if the impeller is made of plastic.

no the thermostat must be working or your engine would not heat up, check to see if your heater hoses are hot if only one is hot you need a heater core, but check your coolent level if the van gets low on coolent it will not let any get to the heater thehope engine keeps it all to keep the engine cool....hope this helps

Check the coolant level. If it's low, what you describe will happen. There is not sufficient coolant to flow through the heater core at idle. At 60mph the water pump is spinning quickly, managing to get some coolant through the heater core, so you get heat until the rpm's drop at idle. If it is due to low level, keep an eye on it to see if it drops again, as you may have a leak.

try changing the thermostat for starters.

If you have the heater directed to the windshield, the AC will turn on. Move the control away from defrost.

first of all check to make sure you put back the correct amount of fluid and then do this start the car up and put antifreeze in it and let it run till it gets to temp you may have an air bubble in the system then put the cap back on right away check the condition of the drive belt

i would check to see if the stat is working right, do you have rear heat on this vech? . if you do you may have a air pocket, the windstars have a metal tube coning from the water pump that gose to the heater core lines for the rear heat and they like to fail. they get a pin hole leak that hard to find, the water pump also likes to fail also, not moving a enough fluid under load the ends of the inmpler wear down

make sure it has plenty of coolant in it if it is low the heater wont work. is there any water in the passenger side floorboard

have mechanic check out your heater core its under the dash. chances are its pouched.