Content

• Steps
• Method 1 of 2: Check at home
• Method 2 of 2: Checking on the Road
• Tips
• Warnings
• What do you need

Your car's thermostat is responsible for controlling the amount of coolant that enters the engine.When the engine warms up, the thermostat closes and prevents coolant from entering the engine until it warms up. Once the engine has warmed up to the desired temperature, the thermostat should open up coolant access to the engine. Sometimes the thermostat breaks and remains closed. This article will show you what to do if the thermostat is stuck and won't open.

Steps

Method 1 of 2: Check at home

1. 1 Look at the car temperature gauge. We can talk about a problem with the thermostat if, after 5-15 minutes of engine operation, the arrow of the temperature gauge moves to the red zone.
2. 2 Stop the vehicle and let the engine cool down, then open the hood. Remove the coolant reservoir cap, remove it from the mountings and drain the fluid into a container. Find the radiator and remove the cover from it.
3. 3 Loosen the radiator drain valve located at the bottom and allow the coolant to drain into the container with the cap until the level is below the level of the upper radiator hose.
   • You may not need to drain the coolant from the radiator, it all depends on how much fluid fits in the tank. You need to drain about 4-8 cups. If the coolant is new, you can reuse it. Otherwise, refill with new fluid.
4. 4 Find a thermostat. Typically, the thermostat housing is located under the upper radiator hose. Using a screwdriver and pliers, unscrew the nipple and remove the thermostat. Bring it indoors.
5. 5 Fill a pot with water and completely immerse the thermostat in it. It should not touch the bottom of the pan.
6. 6 Place a kitchen thermometer in the water and start heating it. Watch the water temperature and thermostat carefully.
   • The thermostat should be closed to 88 ºC. When the water temperature reaches this value, you should see how it opens.
   • When the water temperature reaches 90.6 ºC, the thermostat will already be fully open. If it is still closed, replace it.

Method 2 of 2: Checking on the Road

1. 1 Pay attention if the pointer of the temperature sensor is in a hazardous area. This happens very quickly, so as soon as you notice, turn off the engine.
2. 2 If the hood is not too hot, open it. Otherwise, wait 10 minutes for it to cool down.
3. 3 Carefully touch the upper radiator hose. It can be very hot, so touch it with your fingertip for a split second. Do the same with the bottom pipe.
   • Both pipes must be very warm. If one pipe is very warm and the other cold, the thermostat is stuck.

Tips

• Some newer cars do not have an engine temperature gauge, but only a warning light on the dashboard. When the warning light comes on, find a safe place and turn off the vehicle immediately. The car's engine is already overheated.

Warnings

• Always drain the coolant into a sealable container. It has a sweet smell, but it is very toxic to both humans and animals.
• Touch the engine carefully. It can be extremely hot and you run the risk of burns. If the engine smokes, let it cool longer before touching it.

What do you need

• Container with lid
• Pliers
• Screwdriver
• Pan
• Thermometer