Thermostats control the flow of coolant through your Lincoln Mark 8's engine. The coolant only circulates when the engine's internal temperature reaches about 210 degrees F, after which the running temperature of the engine is maintained. Sometimes thermostats will fail and will need to be replaced to avoid damage to the engine. Changing your Lincoln Mark 8's thermostat is not hard, and can be completed by any home mechanic.
Locate the drainplug on the bottom of the radiator. Unscrew it using the socket wrenches and allow the coolant to drain out into a waste container.
Find the faulty thermostat. It is located directly under the power steering reservoir and has three hoses running from it. Use the screwdriver to remove the hose clamp on the hose entering the engine. Pull the hose off and use the socket set to remove the cover underneath.
Pull the thermostat out and replace it with the new thermostat. Replace the cover, reinstall the coolant hose, and refill the radiator with a 50/50 mixture of water and coolant. Start the car and allow it to heat to 210 degrees F. Observe the in-dash temperature gauges to pinpoint any inconsistencies in temperature.
