Thermostat Housing (Functions, Symptoms & Replacement)

The thermostat housing is the coolant outlet in many internal combustion engines. It is usually located on the engine block or the cylinder head.

The coolant flows continuously through ports in the cylinder head and engine block. It then travels through the thermostat housing to the radiator, where it cools down.

This article discusses everything you need to know about your vehicle’s thermostat housing such as what a thermostat housing does, bad thermostat housing symptoms, thermostat housing replacement, and more.

Let’s Begin!

The wrong reading on the coolant level can lead to a complete malfunction or overheating of the engine.

As soon as you notice that the thermostat housing is not functioning properly, you need to take your car to a mechanic for troubleshooting and check immediately.

Before we move forward, let us try to understand the thermostat adequately before we begin understanding what a ‘s housing is and how it works in our cars.

Also Read: Coolant Reservoir – Everything You Should Know

Bad Thermostat Housing Symptoms

Bad Thermostat Housing Symptoms

A bad thermostat housing is often easy to spot. The warning signs below are not necessarily the only ones that show when a thermostat is defective, but they are the most important and should be treated seriously.

1. High Reading On The Temperature Gauge

The thermostat housing regulates the coolant flow into the radiator.

If the thermostat housing is unfit to inspect the amount of temperature of your engine, then it may not be able to regulate the coolant flowing into it.

Scenarios like this might cause overheating to the engine since the coolant doesn’t completely enter it.

2. Coolant Leaking

You should consider it as a sign of a problem if you find any substance dripping on the floor of your car.

When the thermostat housing refuses to open, coercion can cause many leaks in the coolant hose.

3. Erratic Temperature Readings

Abnormal temperature readings shown on your dashboard may suggest an electrical problem in your car.

As we already know, the thermostat in the housing can specify the temperature in any engine.

However, this might not be possible for the thermostats to determine when to open or close if there is a steady miscommunication.

Coolant can be expelled in an unequal amount or back up, resulting in erratic temperature readings.

4. Overheating Engine

A bad thermostat housing will always cause the engine to overheat, which can be harmful.

Overheating causes engine failures and significant damage to vital parts of the engine.

Repairing such damages may be more expensive than buying a new thermostat housing.

5. Improper Coolant Flow

Improper coolant flow is regarded as a sign of damaged thermostat housing and should be carefully examined by any driver.

When you notice improper coolant flow in your vehicle, lift the hood and remove the radiator’s cover.

Always make sure you look closely at the opening of your car housing before you ignite your engine.

6. Cold Coolant Hose

Open the hood after a protracted period to check for any changes. Ignite the engine and test the coolant hose temperature. Be careful not to touch the engine.

You should feel the temperature of the coolant hose after 10 minutes.

Normally, the hose would have become hotter, and if this didn’t happen, the coolant would be bad.

Can I Drive With A Bad Thermostat Housing?

Thermostat Housing

No, You should not drive if you have bad thermostat housing as this could result in severe damage to your vehicle’s engine.

You should repair the coolant thermostat housing as soon as possible if any damages or leaks are discovered. The leak size and coolant level should be inspected simultaneously.

When you notice any leaks in the vehicle housing, you should immediately bring the vehicle to a trusted repair facility for examination.

Usually, the Electronic control module(ECM), which is responsible for promoting the engine to go into “limp” mode in some crucial cases, might lead to the engine shutting down effectively—further preventing it from being driven too fast.

It is the ECM that ultimately shuts down the vehicle.

When the coolant level is low, the dashboard should display a low coolant indicator to alert the driver before the engine is heated up.

Furthermore, the examination light from the engine may suggest a poor thermostat performance or overheating.

How Often Do Thermostat Housings Need Replacement?

The thermostat housing on vehicles lasts longer than the vehicles thermostat. The thermostat housing is meant to last throughout the vehicle’s lifespan.

But sometimes, the thermostat housing could crack due to heating and cooling or the movement of the rubber coolant hose that is attached to it.

The thermostats and thermostat housing of some vehicles are integrated. It becomes vital to replace these thermostats at regular intervals.

The thermostat housing should be frequently examined for wear or damages if the engine gets heated up or if the radiator of the thermostat is replaced.

How To Replace A Thermostat Housing

It is necessary to cool the engine completely before replacing the thermostat housing.

Using this procedure to replace a damaged thermostat housing will allow you to work on your vehicle’s housing without worrying about it getting hot.

Follow these steps to replace your thermostat housing:

  1. Locate your thermostat housing. The thermostat housing is often located in the engine blog or cylinder head.
  2. Remove the damaged and old parts and unscrew the fasteners holding the housing in place.
  3. Clean the thermostat housing’s gasket or sealing. This ensures that no dirt or debris has built up over the years.
  4. install the new seal on the housing and install it.
  5. After installing thermostat housing, start the engine. The engine will then be brought to normal operating temperatures.
  6. Drain and replace coolant.

Note: Before adding the coolant, all air trapped in the cooling system should be removed. You can use a vacuum tool to remove any air trapped in the cooling system.

You can watch the procedure in this video

Also Read: Ignition Coil Pack – Everything You Need to Know

Frequently Asked Questions

What does the thermostat housing do?

The Thermostat housing acts as a coolant outlet in many internal combustion engines. It is mostly located on the engine block or cylinder head. This engine component houses the thermostat that regulates coolant flow, just as the name suggests.

Can a leaking thermostat housing cause overheating?

Yes, leaking thermostat housing can cause overheating. Substantial coolant loss from the thermostat housing could lead to engine overheating.

What does thermostat housing consist of?

Your vehicle’s thermostat housing is usually made of metal or plastic. It houses the thermostat and controls the flow of coolant to the radiator.

Why is my thermostat housing leaking?

When the engine reaches operating temperature, a damaged thermostat housing can leak engine coolant. It could be caused by a crack or a rupture between the engine and the housing.

How long does it take to fix thermostat housing?

Replacing the thermostat housing usually takes about one to two hours.

What causes thermostat housing to crack?

A worn or failed seal could also cause the thermostat housing to crack or leak. You can have either a separate or integrated thermostat housing made from high-quality metal or plastic. If the housing is damaged, cracked, warped, or otherwise damaged, coolant can leak out.

Do I need to replace my thermostat housing?

If your thermostat housing is bad you should replace it immediately. Both the thermostat housing and thermostat are separate components that can be used separately. The thermostat housing is a cover that covers the thermostat. It also contains an opening for the radiator hose, where water enters and leaves the motor.

How much does it cost to replace the thermostat housing?

On average, thermostat housing replacement costs between $250 to $350 for most vehicles. The labor cost to replace the thermostat housing is between $148-$187. Parts are typically between $101-111.


The thermostat housing regulates coolant intake in the engine bay. The coolant protects the engine from overheating.

It does this by transferring heat from the engine to the radiator bay, which can be dispersed in the air.

You have to be familiar with the functions of the thermostat housing and how it works in your vehicle.

Also, know what signs are indicating malfunctioning housing because the housing is an essential component of your car.

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