How to Flush Toyota Heater Cores
Flushing the cooling system and the heater core on Toyotas removes lime and rust deposits. It is rare for a system to get sufficiently blocked up to reduce its ability to function. If the heating system is failing to function properly after flushing the heater core, the thermostat should be checked. A thermostat stuck open can cause the heat to be reduced, as can a crimped hose to the heater core.
- Moderately Easy
- Set of ¼-inch sockets
- ¼-inch ratchet
- Garden hose
- Container to capture the antifreeze
- 1 can of radiator flush
- 1 can of stop leak and conditioner
Drain the antifreeze from the radiator. There is usually a petcock under the bottom of the radiator where you can drain the system. If this particular year of Toyota has no petcock, then remove the lower hose to drain the system. Reinstall the hose if taken off or close the petcock on the radiator. Pour the radiator flush into the radiator and fill it the rest of the way with water.
Start the engine and turn on the heater. Let it run until it reaches normal operating temperature. Shut the engine off and allow the engine to cool for at least 15 minutes.
Remove the top radiator hose--using the ratchet and proper-sized socket to undo the clamp--at the radiator and point the hose toward the fender well or down where the water will not get any electrical connections wet. Insert a garden hose in the radiator expansion tank. Do not turn on the water yet.
Start the engine and let it run. When the engine reaches its normal operating temperature, the thermostat will open and the water will start to run out of the top radiator hose. As this begins, turn on the water hose a little at a time to keep the expansion tank full of water. The fresh water is going from the expansion tank into the radiator, through the water pump, the engine block, the heater core and back out the top radiator hose. Let the engine flush until the water is clean and clear coming out of the top hose. When this happens, shut off the engine and turn off the garden hose.
Remove the bottom radiator hose, using the ratchet and proper-size socket, or open the petcock on the radiator to drain all the water out of the radiator. Install the bottom hose or close the petcock. Install the top radiator hose. Pour the can of stop leak and conditioner into the expansion tank and fill the radiator, through the expansion tank, with 50 percent antifreeze and 50 percent water.