2001 kia sportage is over heating but has no leaks. the radiator has been flushed but is very rusty inside. The water is rusty inside the radiator. We have checked the resevoir, it is fine. the water circulates in the radiator. the thermostat has been replaced, but needs a gasket.

plugged heater core

unless the water pump is leaking should be OK, If you see water flow after thermostat opens water pump is good, Make sure your fans are working when engine is up to temp.

milky oil means water is mixing with it might be a gasket

if you do not see any obvious leaks under the car and you are still adding water to it, you might have a cracked head gasket which is causing coolant to go into cylinders. If this is the case, this can cause more problems.

yep heater core in dash leaking,sound like heater core rusted out if you used straight water.you need to have radiator and engine block flushed because rusty water is in the entire coolant system, you need flush coolant system replace thermostat add 50/50 antifreeze and water mixture never run straight water because straight water in winter weather will cause water freeze up in cylinder block and crack cylinder block you need antifreeze mixture in coolant system to keep coolant from freezing.

any signs of coolant outside car? smell coolant in car? smoking out exhaust colour?

for the overheating start by flushing the cooling system then try the thermostat and if that dont do change waterpump

Make sure the fan control module has not failed. They tend to do this on Chrysler products. Mine did on my '03 Jeep GC at about 48k miles..

Does the radiator fan operate properly? The radiator fluid level (checked when the engine is cold) must be 'at the cap' with the reserve tank about half-full. Blow out the radiator core with compressed air (from the engine side) to clean it of bugs and other debris. Does the anti-freeze look green or rust brown? If rust colored, the entire cooling system needs to be drained, cleaned with system cleaner, and refilled again with a 50/50 fresh mixture of anti-freeze and water. If combustion gases are leaking into the cooling system through a bad gasket or warped cylinder head, that will cause overheating. Check the radiator cap for condition of it's seal. Occasionally, the water pump impeller will begin slipping on it's drive shaft causing limited water flow through the system. That is checked by reducing the level of fluid in the radiator to just above the core and temporarily removing the thermostat. You will observe water moving rapidly if the pump is working.

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