How to Fix the Thermostat in a 1985 Honda Accord Sedan

Your Accord Sedan's thermostat can fail in an open or closed position

The thermostat on a 1985 Honda Accord sedan allows coolant to enter the engine from the radiator when it reaches a set operating temperature. The thermostat is designed to open only when the engine reaches this set temperature. Thermostats can be purchased in a variety of temperature ranges based on your driving conditions and the climate where you drive. If your temperature gauge is regularly showing a lower temperature than normal, your thermostat may be stuck open. If the the temperature is rising well above the middle of the temperature gauge, your Accord's thermostat could be stuck closed or partially closed.

Things You'll Need

• Thermostat
• Coolant
• Socket set
• Drain/catch pan

Instructions

1. Remove the upper radiator hose. Your 1985 Accord's upper radiator hose runs from the top of the radiator to an inlet on the engine. It is attached with a clamp that must be removed. Remove only the end that connects to the engine; leave the hose connected at the radiator.

2. Catch excess coolant. Some coolant will come out of the hose once it is removed. Have a drain pan handy to keep coolant from landing on the ground. Try to support the upper radiator hose on the engine block so that it does not fall down and leak more coolant.

3. Remove the thermostat housing. With the hose removed, the thermostat housing, connected to the engine block, must be unbolted. One the bolts are removed, the housing will separate easily.

4. Remove and replace the thermostat. Remove the thermostat from its housing and discard the old thermostat. Place the new thermostat in the housing.

5. Tighten the thermostat housing. Replace the thermostat housing on the engine block, and tighten it down using the bolts that were removed in Step 3. Hand tighten the bolts at first, and then make them snug using a ratchet. If you over-tighten the bolts, they could be difficult to remove when the thermostat next requires service.

6. Reattach the radiator hose to the thermostat housing and tighten it using the clamp removed in Step 1. If the hose clamp is damaged, you may want to replace it with a new one.

7. Refill the coolant since some coolant was lost when the radiator hose was disconnected in Step 1. You can use the coolant caught in your drain pan, or you may also put in new coolant.

Tips & Warnings

• Use a drain pan when removing the upper radiator hose, as engine coolant is dangerous for animals and children if left on the ground. Its sweet smell can attract animals, who may drink it with fatal consequences.

References

• 2CarPros: Honda Accord Repair Questions
• AutoMedia: Thermostat Replacement