What Size Thermostat For 350 Chevy

What Size Thermostat For 350 Chevy ( 2 Main Types)

When it comes to the heart and soul of American muscle, the 350 Chevy engine stands tall as an automotive legend, ready to unleash its raw power on the open road.

But behind the rumbling exhaust and the adrenaline-pumping horsepower lies a critical component that often goes overlooked – the thermostat.

Choosing the right size thermostat for your 350 Chevy is like selecting the perfect conductor for a symphony; it orchestrates the engine’s temperature with precision, ensuring that this mechanical maestro performs at its peak.

So, as we dive into the world of thermostats for the 350 Chevy, prepare to uncover the secrets of thermal harmony that keep this iconic engine roaring with life and vitality.

What Size Thermostat For 350 Chevy

Table of Contents

What Size Thermostat For 350 Chevy

The recommended thermostat size for a 350 Chevy engine is typically 195 degrees Fahrenheit (or 91 degrees Celsius).

This thermostat helps maintain the engine at an optimal operating temperature for performance and fuel efficiency.

Understanding the 350 Chevy Engine

The 350 Chevy engine is a venerable powerplant with a rich history and a well-deserved reputation for its performance and reliability.

This iconic V8 engine has been a cornerstone of American automotive culture for decades. Introduced in various iterations since the 1960s, it has powered a wide range of vehicles, from classic muscle cars to trucks and SUVs.

One of the defining characteristics of the 350 Chevy engine is its displacement, measuring 350 cubic inches or approximately 5.7 liters.

This displacement is a significant contributor to its torque-rich performance, making it a popular choice for applications that require ample low-end power, such as towing and off-roading.

The 350 Chevy engine is often praised for its versatility, with variants tailored for different purposes, including economy, performance, and heavy-duty use.

The engine’s architecture is a marvel of engineering, featuring a cast iron block and cylinder heads in most iterations. The V8 configuration allows for a balanced and smooth power delivery, making it suitable for both everyday driving and high-performance applications.

The crankshaft, pistons, camshaft, and valvetrain are meticulously designed and balanced to maximize efficiency and power output.

Throughout its history, the 350 Chevy engine has undergone numerous changes and improvements, adapting to evolving emissions regulations and technological advancements.

Early iterations used carburetors for fuel delivery, while more recent models incorporate electronic fuel injection systems for improved efficiency and reduced emissions.

Regular maintenance is essential to ensure the engine’s longevity and performance. Routine tasks such as oil changes, coolant flushes, and timing chain replacements are crucial for preventing common issues like overheating and oil leaks.

Enthusiasts often embrace aftermarket modifications to enhance the engine’s performance further, including upgrades to camshafts, intake manifolds, and exhaust systems.

The 350 Chevy engine’s significance extends beyond its mechanical prowess. It has left an indelible mark on American automotive culture, symbolizing power, performance, and the freedom of the open road.

It has a storied history in motorsports and racing, where its robust design and reliability have contributed to numerous victories and championships.

Whether it’s the rumble of a classic muscle car or the roar of a modified hot rod, the unmistakable sound of a 350 Chevy engine evokes nostalgia and excitement, reminding us of its enduring legacy in the world of automobiles.

What Size Thermostat For 350 Chevy

Basics of Engine Cooling

Effective engine cooling is essential for maintaining an optimal operating temperature and ensuring the longevity and efficiency of the 350 Chevy engine.

Understanding the basics of engine cooling is fundamental for any vehicle owner or enthusiast. The cooling system plays a critical role in preventing overheating and ensuring the engine operates within its ideal temperature range.

The engine cooling system consists of several key components

Radiator: The radiator is the heart of the cooling system. It is typically located at the front of the vehicle and contains a network of small tubes and fins. As hot coolant flows through these tubes, heat is dissipated into the surrounding air, cooling the liquid.

Water Pump: The water pump is responsible for circulating coolant (usually a mixture of water and antifreeze) through the engine and radiator. It is typically driven by a belt connected to the engine’s crankshaft.

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Thermostat: The thermostat acts as a valve that regulates the flow of coolant between the engine and the radiator. It remains closed when the engine is cold, allowing it to heat up quickly, and opens when the engine reaches its operating temperature, allowing coolant to flow and maintain that temperature.

Coolant: Coolant, often a mixture of water and antifreeze, helps lower the freezing point of the liquid while also raising its boiling point. It contains corrosion inhibitors to protect the engine and cooling system components.

Fans: Electric fans or mechanical fans are used to increase airflow through the radiator, especially when the vehicle is stationary or moving at low speeds. This helps dissipate heat more efficiently.

The cooling system’s primary function is to manage the engine’s temperature. Engines operate most efficiently within a specific temperature range, typically around 195°F (90.5°C).

This temperature range allows for efficient combustion and oil performance while minimizing emissions. Below this range, fuel efficiency drops, and engine wear increases. Above this range, overheating can lead to engine damage.

The process of engine cooling involves the following steps

Coolant Circulation: The water pump circulates coolant through the engine block and cylinder heads, where it absorbs heat from the combustion process.

Heat Dissipation: As the hot coolant flows through the radiator, heat is transferred to the radiator’s fins and dissipated into the surrounding air.

Thermostat Regulation: The thermostat monitors the engine’s temperature and controls the flow of coolant to maintain the desired operating temperature.

Fan Operation: Fans, whether electric or mechanical, help enhance cooling airflow through the radiator, especially when the vehicle is not in motion.

Pressure Control: The cooling system operates under pressure, which raises the boiling point of the coolant and helps prevent overheating.

What Size Thermostat For 350 Chevy

Types of Thermostats

Thermostats are crucial components within a vehicle’s cooling system, responsible for regulating the flow of coolant and maintaining the engine’s operating temperature within the desired range. There are different types of thermostats available, each with its own characteristics and advantages.

Understanding the various thermostat types is essential when selecting the most appropriate one for a 350 Chevy engine. Here, we explore the two primary categories: mechanical thermostats and electronic thermostats.

Mechanical Thermostats

Traditional Mechanical Thermostats:

These are the most common type of thermostats found in older vehicles, including many 350 Chevy engines.
Operation relies on a wax-filled element or a bimetallic coil.

When the engine is cold, the thermostat remains closed, blocking coolant flow to the radiator.
As the engine warms up, the thermostat gradually opens, allowing coolant to flow and regulating the engine’s temperature.

These thermostats are simple, reliable, and cost-effective. They are suitable for many applications but may have limitations in precise temperature control.

High-Flow Performance Thermostats:

Designed for high-performance engines or heavy-duty applications. Feature a larger opening or bypass to allow more coolant flow, which can help maintain lower temperatures under extreme conditions.
Popular among enthusiasts and those with modified engines.

Fail-Safe Thermostats:

Equipped with a safety feature that allows them to remain partially open even if they fail. This prevents complete coolant flow blockage in case of thermostat failure, reducing the risk of engine overheating.

Electronic Thermostats

Electrically Controlled Thermostats:

More common in modern vehicles with advanced engine management systems. Operate based on electronic signals from the engine control unit (ECU).

Allows for precise control of the thermostat’s opening and closing, optimizing engine performance and emissions. Often integrated with other engine systems for improved efficiency.

Variable-Flow Thermostats:

Provide dynamic control of coolant flow based on real-time conditions. Can adjust coolant flow rates based on factors like engine load, temperature, and driving conditions. Enhance fuel efficiency by optimizing the engine’s operating temperature.

Smart Thermostats:

The latest advancement in thermostat technology. Utilize sensors and data processing to continuously adapt coolant flow to changing conditions.

Aim to achieve the optimal balance between engine performance, emissions, and efficiency in real-time.
Commonly found in modern, high-tech vehicles.

Choosing between mechanical and electronic thermostats for a 350 Chevy engine depends on factors such as the engine’s age, intended use, and compatibility with the vehicle’s electrical system.

Factors Affecting Thermostat Size Selection

Selecting the correct thermostat size for a 350 Chevy engine is critical to ensure efficient cooling and optimal engine performance. Several factors should be taken into account when choosing a thermostat size, as it directly impacts how the engine maintains its operating temperature. Here are the key factors to consider.

Engine Size and Displacement

The 350 Chevy engine has a 350 cubic inch (5.7-liter) displacement, which is a key factor in thermostat selection. Larger engines often require thermostats with higher flow rates to accommodate their greater coolant needs.

Desired Operating Temperature

The ideal operating temperature for most 350 Chevy engines is around 195°F (90.5°C). However, some applications may have different temperature requirements.

Selecting a thermostat with the appropriate temperature rating is crucial for maintaining consistent engine performance and emissions.

Climate and Driving Conditions

Consider the typical climate and driving conditions in which the vehicle operates. In hotter climates or under heavy load conditions (e.g., towing), a lower temperature thermostat (e.g., 180°F) might be preferred to help prevent overheating.

In colder climates, a higher temperature thermostat (e.g., 195°F) may be necessary to ensure the engine reaches its optimal temperature for fuel efficiency and emissions control.

Type of Coolant Being Used

The type of coolant used in the engine can affect thermostat selection. Some coolants are specifically formulated for use with certain thermostat temperature ratings. Ensure compatibility between the chosen thermostat and the coolant type.

Vehicle Modifications

If the 350 Chevy engine has undergone performance modifications (e.g., high-performance camshaft, aftermarket cooling system), consider how these changes affect coolant flow and temperature.

Performance upgrades may necessitate a different thermostat size to maintain the desired operating temperature.

Manufacturer Recommendations

Consult the manufacturer’s recommendations for thermostat size and temperature rating for your specific 350 Chevy engine model and year.

Manufacturer guidelines can provide valuable insights into the optimal thermostat size and temperature for your engine.

Cooling System Design

Evaluate the overall design of the vehicle’s cooling system, including the radiator size and fan setup. Ensure that the chosen thermostat size complements the existing cooling system components for efficient heat dissipation.

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Future Modifications and Goals

Consider any future modifications or goals you have for the vehicle. If you plan to make additional engine or performance upgrades, choose a thermostat size that accommodates these changes.

Expert Advice

When in doubt, seek advice from automotive experts, mechanics, or forums specific to 350 Chevy engines.
Professionals can offer valuable insights based on their experience and expertise.

What Size Thermostat For 350 Chevy

Calculating the Correct Thermostat Size

Calculating the correct thermostat size for a 350 Chevy engine involves considering various factors to ensure that the chosen thermostat effectively regulates the engine’s temperature. Here’s a step-by-step guide to help you calculate the appropriate thermostat size.

Determine the Desired Operating Temperature:

Identify the ideal operating temperature for your 350 Chevy engine. For most applications, around 195°F (90.5°C) is considered optimal.

Adjust this temperature if your engine has specific requirements due to modifications or unique conditions (e.g., hotter climate, heavy towing).

Consider the Engine’s Displacement

Recognize that the 350 Chevy engine has a 350 cubic inch (5.7-liter) displacement. Larger engines may require thermostats with higher flow rates to accommodate their greater coolant needs.

Assess Climate and Driving Conditions

Evaluate the typical climate and driving conditions in which your vehicle operates. In hotter climates or under heavy load conditions, you may opt for a lower temperature thermostat (e.g., 180°F) to prevent overheating.

In colder climates, a higher temperature thermostat (e.g., 195°F) may be necessary to ensure efficient combustion and emissions control.

Check Manufacturer Recommendations

Refer to the manufacturer’s recommendations for your specific 350 Chevy engine model and year. Manufacturers often provide guidelines on thermostat size and temperature rating to maintain optimal performance and reliability.

Evaluate Vehicle Modifications:

Consider any performance modifications made to the engine, as they can impact coolant flow and temperature.

Upgrades like high-performance camshafts or aftermarket cooling systems may require adjustments to thermostat size.

Analyze Cooling System Design

Examine the overall design of your vehicle’s cooling system, including the radiator size and fan setup. Ensure that the chosen thermostat size complements the existing cooling system components to maintain efficient heat dissipation.

Future Modifications and Goals

Think about any future modifications or goals you have for your vehicle. If you plan to make additional engine or performance upgrades, choose a thermostat size that accommodates these changes.

Calculate the Temperature Differential

Calculate the temperature differential by subtracting the desired operating temperature (e.g., 195°F) from the thermostat’s temperature rating.

For example, if you want to maintain 195°F and your thermostat is rated at 195°F, the temperature differential is 0°F.

Determine the Flow Rate

Consider the flow rate or gallons per minute (GPM) of the thermostat. A higher flow rate allows for more coolant circulation, which can help maintain a stable temperature.

Make Your Selection

Based on the calculated temperature differential and flow rate, choose a thermostat that meets your requirements. Ensure the selected thermostat is compatible with your engine and cooling system.

Consult with Experts

If you’re uncertain about your calculations or thermostat selection, consult automotive experts or mechanics for guidance. Professionals can provide valuable insights and recommendations based on their experience.

Installation and Replacement of a Thermostat in a 350 Chevy Engine

Proper installation or replacement of a thermostat is essential for maintaining the cooling system’s functionality and preventing overheating issues in a 350 Chevy engine. Here’s a step-by-step guide on how to install or replace a thermostat.

Gather Necessary Tools and Materials

New thermostat
Gasket or seal (if not included with the thermostat)
Wrenches or sockets (appropriate size for thermostat housing bolts)
Drain pan
Gasket scraper or razor blade
Rag or shop towels

Safety Precautions

Ensure the engine is cool before starting the installation or replacement. Always use safety goggles and gloves when working with coolant to prevent skin and eye irritation.

Locate the Thermostat Housing

Identify the thermostat housing on your engine. It’s typically connected to the upper radiator hose.

Drain the Coolant

Position a drain pan beneath the radiator drain valve. Open the drain valve and allow the coolant to drain into the pan.

Remove the Thermostat Housing

Using the appropriate wrench or socket, carefully remove the bolts securing the thermostat housing.
Gently pry the housing away from the engine block. Be prepared for some residual coolant to spill out.

Remove the Old Thermostat

Lift out the old thermostat, taking note of its orientation (which way it’s facing). Remove any remnants of the old gasket or seal from both the thermostat housing and the engine block using a gasket scraper or razor blade.

Prepare the New Thermostat

Check the new thermostat to ensure it’s the correct size and has the same temperature rating as the old one.
If a gasket or seal isn’t pre-attached to the thermostat, apply a thin layer of gasket sealant to both sides of the new gasket.

Install the New Thermostat

Place the new thermostat into the engine block in the same orientation as the old one.
Position the thermostat housing over the thermostat. Reattach the housing by securing the bolts, ensuring it’s snug but not overtightened.

Refill with Coolant

Close the radiator drain valve. Using a funnel, slowly pour the coolant back into the radiator, taking care not to spill. Monitor the coolant level in the radiator and add more as needed until it reaches the recommended level.

Bleed the Air from the Cooling System

Start the engine and let it run with the radiator cap off. As the engine warms up, air bubbles may escape from the open radiator. Keep topping off the coolant as needed.

Once the engine reaches its operating temperature and the thermostat opens (you’ll notice the coolant level drop), replace the radiator cap.

Check for Leaks

Examine the thermostat housing and surrounding area for any signs of coolant leaks. Tighten any bolts or connections as necessary to stop leaks.

Dispose of Old Coolant Properly

Collect the old coolant in a container and dispose of it at an authorized recycling or disposal facility.

Test the Thermostat

Take your vehicle for a test drive to ensure the thermostat is functioning correctly. Monitor the engine temperature gauge to verify that it stabilizes within the desired operating range.

Testing and Monitoring the Thermostat in a 350 Chevy Engine

Regularly testing and monitoring the thermostat in your 350 Chevy engine is essential to ensure that it functions correctly and helps maintain the engine’s optimal operating temperature. Here’s a comprehensive guide on how to test and monitor the thermostat.

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Safety Precautions

Ensure the engine is cool before performing any tests or inspections. Use safety goggles and gloves when working with coolant to prevent skin and eye irritation.

Visual Inspection

Open the hood and visually inspect the thermostat and its housing. Look for any visible signs of coolant leaks, corrosion, or damage to the thermostat or housing.

Engine Temperature Gauge

Start the engine and let it idle. Monitor the engine temperature gauge on the dashboard. The gauge should gradually rise to the normal operating temperature (around 195°F or 90.5°C) and then stabilize.

If the temperature gauge remains in the “cold” range or consistently exceeds the normal operating temperature, it may indicate a thermostat problem.

Coolant Flow Test

Observe the upper radiator hose when the engine is running. As the engine warms up, the thermostat should open, allowing coolant to flow through the hose and into the radiator.

If the upper radiator hose remains cool or the coolant flow appears restricted even after the engine reaches operating temperature, it may suggest a thermostat issue.

Infrared Thermometer Test

Use an infrared thermometer to measure the temperature of the thermostat housing while the engine is running.

The thermostat housing should reach a similar temperature to the engine’s operating temperature. A significantly lower temperature at the housing may indicate a thermostat that is stuck in the open position, not allowing the engine to reach its optimal temperature.

Thermostat Function Test

Remove the thermostat from the engine for testing. Fill a container with water and bring it to a boil. Carefully lower the thermostat into the boiling water using a wire or a heat-resistant tool.

Observe the thermostat’s behavior:

It should remain closed while in the boiling water. As it heats up, it should gradually open. If the thermostat does not open or opens too soon, it may be faulty and should be replaced.

Replacing the Thermostat

If any of the tests indicate a faulty thermostat, it’s advisable to replace it. Follow the installation and replacement steps outlined in Section VII of this guide.

Regular Monitoring

Continue to monitor the engine temperature gauge during regular driving. Pay attention to any fluctuations in temperature, overheating, or signs of coolant leaks. If you notice any irregularities, address them promptly to prevent engine damage.

Scheduled Maintenance

Include thermostat inspection and testing as part of your vehicle’s scheduled maintenance. Follow manufacturer recommendations for thermostat replacement intervals.

Testing and monitoring the thermostat in your 350 Chevy engine is a proactive approach to maintaining the engine’s cooling system.

Upgrades and Performance Considerations for the 350 Chevy Engine Thermostat

Upgrading the thermostat in a 350 Chevy engine can have a significant impact on engine performance, especially if you’re looking to optimize cooling efficiency or fine-tune temperature control. Here are some considerations for thermostat upgrades and performance enhancements.

High-Flow Thermostats

High-flow thermostats are designed to allow more coolant flow at lower temperatures, which can help in cooling the engine more effectively.

They are often used in high-performance or modified engines that generate more heat.
High-flow thermostats can help maintain lower temperatures during heavy-load situations, such as towing or racing.

Coolant Additives

Consider using specialized coolant additives that enhance the efficiency of the cooling system. Some additives claim to improve heat transfer, reduce corrosion, and prevent coolant foaming, all of which can contribute to better cooling performance.

Electric Fans

Upgrading to an electric cooling fan can provide better control over engine temperature. Electric fans can be activated as needed, allowing for precise cooling, especially in traffic or at low speeds. Consider a dual-fan setup for even more efficient cooling.

Thermostat Temperature Rating

Adjusting the thermostat’s temperature rating can impact engine performance. Lower temperature thermostats (e.g., 180°F) may be suitable for hot climates or racing applications, but they can reduce fuel efficiency in everyday driving.

Higher temperature thermostats (e.g., 195°F) can enhance fuel efficiency and emissions control but may run slightly hotter.

Performance Radiator

Installing a larger or more efficient radiator can complement thermostat upgrades. Performance radiators can dissipate heat more effectively, especially in high-performance or heavy-duty applications.

Cooling System Modifications

Consider other cooling system upgrades such as a high-capacity water pump, larger-diameter hoses, or an upgraded coolant reservoir. These modifications can help improve overall cooling performance.

Engine Tuning

If you’re upgrading your 350 Chevy engine for performance, consider engine tuning adjustments to optimize the thermostat’s operation.

A professional tuner can adjust the engine’s operating parameters, including fan activation points and thermostat behavior, for maximum performance.

Thermostat Housing Modifications

Some enthusiasts modify the thermostat housing to increase coolant flow or accommodate larger thermostats. This should be done with caution, as improper modifications can lead to cooling system issues.

Regular Maintenance

Regardless of upgrades, regular maintenance of the cooling system is crucial. Keep coolant levels topped up, check for leaks, and ensure the radiator and cooling system components are in good condition.

Consider Expert Advice

If you’re unsure about which upgrades are suitable for your 350 Chevy engine or how to implement them effectively, consult with automotive experts or performance specialists.

FAQ: What Size Thermostat for a 350 Chevy Engine

What size thermostat should I use for a 350 Chevy engine?

The size of the thermostat for a 350 Chevy engine typically depends on the year, make, and model of your vehicle. In general, most 350 Chevy engines use a 195-degree Fahrenheit thermostat.

How do I determine the correct thermostat size for my 350 Chevy engine?

To find the right thermostat size, consult your vehicle’s owner’s manual or check with the manufacturer’s recommendations. In many cases, a 195-degree Fahrenheit thermostat is a safe choice.

Can I use a thermostat with a different temperature rating for my 350 Chevy engine?

While it’s possible to use a thermostat with a different temperature rating, it’s essential to consult with a mechanic or refer to your vehicle’s specifications to ensure it won’t affect engine performance or cause overheating.

Are there performance thermostats available for a 350 Chevy engine?

Yes, there are performance thermostats with lower temperature ratings (e.g., 180 or 160 degrees Fahrenheit) available for some 350 Chevy engines. These can help keep the engine cooler but should be chosen carefully to prevent issues in extreme weather conditions.

What are the potential problems if I install the wrong size thermostat in my 350 Chevy engine?

Installing the wrong size thermostat can lead to overheating or inefficient engine performance. It can also affect your vehicle’s emissions and fuel efficiency.

Can I install a thermostat with a higher temperature rating for my 350 Chevy engine in colder climates?

Yes, in colder climates, using a thermostat with a slightly higher temperature rating can help the engine reach its optimal operating temperature faster, but consult your vehicle’s specifications or a mechanic for guidance.

How often should I replace the thermostat in my 350 Chevy engine?

Thermostats typically last several years, but it’s a good practice to replace them during regular engine maintenance, which is usually every 30,000 to 50,000 miles or as recommended by your vehicle’s manufacturer.

Are there any special considerations for high-performance 350 Chevy engines when selecting a thermostat size?

High-performance engines may have unique cooling requirements. It’s essential to consult with experts or the engine builder for specific thermostat recommendations in these cases.

Can I install a thermostat for a 350 Chevy engine myself, or should I have a professional do it?

If you have basic automotive repair skills and the necessary tools, you can install a thermostat yourself. However, if you’re unsure or have a high-performance engine, it’s recommended to seek professional assistance.

Where can I purchase the right thermostat for my 350 Chevy engine?

You can purchase the correct thermostat for your 350 Chevy engine from auto parts stores, online retailers, or through your vehicle’s dealership. Ensure you have your vehicle’s specifications when shopping to get the right thermostat.


In conclusion, selecting the right size thermostat for a 350 Chevy engine is a critical decision for maintaining optimal engine performance and longevity.

The choice between a 160°F or 195°F thermostat should be based on a careful consideration of your specific needs and climate conditions.

A 160°F thermostat may be suitable for warm climates and high-performance applications, while a 195°F thermostat is better suited for colder climates or when optimal engine efficiency is required.

Consulting with a knowledgeable mechanic or following the manufacturer’s recommendations is the best approach to ensure that your 350 Chevy engine operates at its best temperature range, maximizing both power and fuel efficiency.

Proper thermostat selection is a small yet essential aspect of overall engine maintenance that can significantly impact the longevity and performance of your vehicle.






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