Maintaining the correct operating temperature keeps your engine running efficiently and prevents damage from excessive temperatures. Once the engine coolant is hot, the radiator valve (also called a thermostat) keeps the engine temperature within the correct range by regulating the flow through the rad.
Of the cooling system components, the thermostat is the one most likely to fail. If so, you may have an overheating problem that will cost you a fortune to fix, or the engine may not reach optimal temperature. When a thermostat needs to be replaced, parts are usually less than $100, with a few exceptions, as long as no additional damage is caused.
1. Working principle of radiator valve
Car thermostats are designed to be simple yet effective. It usually consists of a cylinder made of metal or plastic that contains a temperature-sensitive element filled with wax, a spring, and a valve.
Temperature-sensitive components contain wax, which expands when the temperature increases and contracts when the temperature decreases. This movement of the wax element is transmitted to the valve via the spring. When the engine is cold, the spring causes the valve to close, preventing coolant from flowing to the radiator.
As the engine warms up, the wax element expands, pushing on the spring and ultimately causing the valve to open. This allows coolant to flow through the radiator and regulate engine temperature. It usually ranges from 180 degrees Fahrenheit to 200 degrees Fahrenheit. The thermostat also has a bypass that allows a small amount of coolant to circulate even when the valve is closed, helping to warm up the engine faster.
2. What’s wrong with the thermostat?
Some problems that can occur with your thermostat or radiator valve include:
The following problems may occur with your car thermostat:
- Keep it open. If the thermostat is open, coolant will constantly circulate through the radiator, causing the engine to run cooler than it should. This can reduce fuel efficiency, and performance, and even cause you to fail a smog test.
- Stay closed. If the thermostat is closed, coolant will not be able to circulate through the radiator, causing the engine to overheat and causing damage to the engine or other components.
- Worn springs. Over time, the springs within your thermostat can weaken. The thermostat may not open or close as needed.
- The wax element failed. If the wax element inside your thermostat is damaged or leaking, it won’t be able to expand and contract properly.
3. Steps to replace the radiator valve (thermostat)
Replacing a thermostat or radiator valve is usually a simple process, even for novice DIYers. Depending on the position of the engine, it may take 30 minutes or less, or it may take several hours. You first need to find the location of the thermostat, usually on the upper end of the engine block just below the neck of the housing where the radiator hose connects. Some thermostats are more complex, integrating a housing, a coolant sensor, and one or more water outlets.
Gather your tools from there. You will need the following:
- Slotted screwdriver
- Ratchet and socket set
- Radiator hose clamp
- a drip tray
- engine coolant
- New thermostat and gasket
- Hand and eye protection
Allow the engine to cool for 30 minutes to an hour before turning on the cooling system. Otherwise, hot coolant or steam could escape and seriously burn you or others nearby.
1) Drain the coolant
Place a drain pan or bucket under the stopcock on the Ladd. If your radiator does not have a drain hose, place a bucket under the lower radiator hose. Open the valve or remove the hose from the radiator and drain the coolant.
2) Remove the thermostat housing
It may be necessary to move or remove some parts, pipes, or engine cover to reach the thermostat housing. Once inside, remove the hose with a hose clamp or screwdriver and pull the hose out. You may need to use a flat-blade screwdriver to remove the hose from the outlet. Then, loosen the thermostat housing bolts from the engine block.
3) Replace thermostat
With the housing removed, you should be able to see the thermostat as if it were a separate piece. It’s sort of UFO-shaped, with a flat ring and washers on both sides. Some radiator valves are integrated into the housing and replaced as components. After removing the thermostat, thoroughly clean the mounting surfaces of the engine block and thermostat housing. Install new parts, making sure the thermostat is oriented correctly for coolant flow.
4) Reinstall the thermostat housing
Install the housing with the new gasket and tighten it to the manufacturer’s specifications.
5) Add engine coolant
Add a 50-50 mixture of distilled water and concentrated engine coolant to the radiator. Make sure the type of coolant you choose is appropriate for your car’s make to prevent unexpected reactions.
6) Bleed the air out of the cooling system
Start the engine and let it run for a few minutes to check for leaks. Then, shut down the engine and allow it to cool. Check the coolant level and add more coolant if necessary.
4. How to maintain radiator valves and find problems
How to prevent thermostat problems? The most important thing you can do is change your engine coolant according to your maintenance schedule. If the coolant is not strong enough or becomes acidic, it may cause the thermostatic radiator valve to become clogged or corroded.
If you have the following symptoms, it may be too late:
- Check Engine Light Comes On And Displays Temperature-Related DTCs
- The thermometer reading is too high or too low under normal operating conditions
- You often notice symptoms of overheating but no signs of leaking head gaskets or water pump problems
- Not enough heat in the cabin on cold days
For a small, inexpensive component, the thermostat plays a huge role in keeping your engine healthy and running efficiently. Prevent problems by performing routine cooling system maintenance and, if a problem occurs, replace the radiator valve or thermostat as soon as possible.
5. Frequently asked questions
Here are answers to frequently asked questions about replacing your radiator valve.
1) Can I replace the radiator valve myself, or do I need a professional?
Typically, DIYers can replace a thermostat or radiator valve with just a few common tools and basic mechanical knowledge.
2) How do I know if my radiator valve needs replacing?
If you notice inconsistent temperature readings, a DTC related to engine cooling, an overheated engine, or cooler-than-normal cabin temperatures, you may need to replace your thermostat.
3) What are the signs of radiator valve failure?
Typical signs of a failed radiator valve include the Check Engine light coming on, poor vehicle cooling, and the engine running too cold or too hot on the gauge.
4) Can I replace my existing valve with any type of valve?
Thermostatic valves come in many shapes, sizes, and temperature ratings. Choose the right product specifically for your car or you may encounter serious operating problems.
6. Conclusion
This guide summarizes how to replace a radiator valve. By the end of this article, you will be able to replace a radiator valve yourself without calling a professional repairman.
（https://www.autozone.com/diy/radiator/how-to-change-a-radiator-valve）
