1. there is an air bubble in the line. 2. the heater core it self is really dirty inside or it is blocked up. feel the hoses going to the heater core. one should be real hot the other just slitely cooler. if this is true then the core is good. the problem may be in the on/off controls. depending on the vechele, a control switch may be in the heater hose or in the heater core. the input hose is hot, the output hose cool. the switch may be stuck so it is blocking the water getting to the core. have some one watch the switch under the hood while some one is in the vechele working the switch on and off.
the heater core could be pluged or the heater control valve is stuck closed
1 of a 100 but the 1st to check . BAD THERMOSTAT
Most common things are Thermostat or a bad heater core but could also be something blocking the door down by the heater core. I changed my Thermostat and Heater control Valve to find out a pencil fell in the defroster and prevented the door from closing. Hope this helps.
By overheating which will cause a change in the thermostat materials construction.
A blocked heater hose could cause a leak. A stopped up heater core could as well. Or the connector in the Windstar could be cracked.
either your low on anti-freeze or the thermostat is broken. i just changed my thermostat today and i cost $11 so it won't hurt to get it replaced even if your not sure its broken.
engine thermostat, fan motor,or fuse.
The thermostat may be stuck in the open position, so that the water is not getting hot enough.
low water, bad thermostat, vacuum door not working, clogged up heater core, heater valve broken........
Yes it can cause it to overheat but first check your thermostat. That would be the 1st cheapist thing to do before you did anything else. I got an 85 regal(overheating) and the thermostat or the heater core is the problem im getting them both replaced tomorrow and will let know of how it runs.
There are a bunch of things that can cause that. Water pump, thermostat, switch not engaging the heater, air in the heater core, not enough antifreeze in the cooling system. do i need a new thermostat
Your heater relay switch may be bad
the thermostat may be stuck open or the heater core may be plugged the thermostat may be stuck open or the heater core may be plugged
Thermostat and/or heater core may be defective
Bad thermostat not turning it off or measuring incorrect temp
Running a vehicle without a thermostat will cause it to take longer to warm up and your interior heater may not blow hot air.
Generally, the cause is a thermostat that is stuck open. A good way to test is to turn the heater control to off for a few minutes, then turn on and see if you have heat. If you do, you need a new thermostat.
Heater core is stopped up or thermostat is stuck open.
Any heater that only blows luke warm air isn't getting warm or hot water to the coil. This sounds like a problem with the thermostat not closing, and allowing the engine to heat the water properly for the heater.
low coolant? Bad thermostat? Climate control not sensing proper temperature? Heater core plugged or restricted? Heater core airbound?
Possible cause thermostat bad stuck open