Engine Coolant Thermostat Guide for the 1973-1988 Buick Regal
Ensure your Regal's V6 or V8 engine runs at the perfect temperature by choosing the right thermostat.
- A thermostat can fail stuck open (engine runs cold) or stuck closed (engine overheats). Overheating can cause severe engine damage.
- For a stock 1973-1988 Regal, an ACDelco or Gates thermostat with the factory-specified temperature rating is the most reliable choice.
- Performance brands like Edelbrock and Mr. Gasket offer high-flow and lower-temperature options for modified engines.
- Replacement is simple for most DIY mechanics and requires a new gasket to prevent leaks.
Is Your Regal's Thermostat Failing?
A thermostat typically fails in one of two ways: stuck open or stuck closed. Both can cause problems for your classic Buick.
- Stuck Open: Coolant flows to the radiator constantly. This makes it very difficult for your engine to warm up, especially in colder weather. Symptoms include a temperature gauge that stays low, a heater that blows lukewarm or cold air, and a decrease in fuel economy.
- Stuck Closed: This is the more serious failure. Coolant is blocked from reaching the radiator, trapping heat within the engine. This will cause the engine to overheat very quickly, leading to potential engine damage like warped heads or a blown head gasket. Symptoms are a temperature gauge that rapidly spikes into the red, steam from under the hood, and a sweet smell of boiling coolant. If you suspect a stuck-closed thermostat, shut off the engine immediately to prevent damage.
Choosing the Right Aftermarket Thermostat
For a vehicle like the 1973-1988 Regal, you have several good aftermarket options. The most important factor is choosing the correct temperature rating specified for your particular engine (V6 or V8) and year. Using the wrong temperature can affect performance and emissions.
Tier 1: OEM-Equivalent & Trusted Brands
For most owners looking for stock performance and reliability, these brands are the safest bet.
- ACDelco: As the original equipment manufacturer for General Motors, ACDelco parts are the benchmark for fit and function. Choosing an ACDelco thermostat is the closest you can get to installing a factory part.
- Gates: A highly respected name in aftermarket cooling and rubber components. Gates thermostats are a reliable alternative to OEM and are trusted by many mechanics.
Tier 2: Performance & High-Flow Brands
If you have a modified engine or specific cooling goals, these brands offer different temperature ratings and flow characteristics. Be aware that a lower-temperature thermostat (e.g., 160°F) is not always better for a street-driven car, as it can prevent the engine from reaching its most efficient operating temperature.
- Edelbrock: Known for performance, Edelbrock offers high-flow thermostats made with durable brass, copper, and stainless steel components. They are designed for high-performance applications and can help provide consistent cooling under load.
- Mr. Gasket: Another performance-focused brand offering high-flow thermostats, often at lower temperature ratings. User reviews are mixed, with some reporting excellent performance and others experiencing premature failures.
- Mishimoto: A popular brand in the performance cooling world, Mishimoto is another option for those seeking a thermostat for a modified or high-performance Regal.
Tier 3: Standard Aftermarket
These brands are widely available and often budget-friendly, but quality can be inconsistent.
- Motorad: This brand has very mixed reviews. While they manufacture thermostats for many companies, some users have reported early failures. Their "Fail-Safe" models are designed to lock in the open position upon failure, which prevents overheating but requires immediate replacement to restore normal function.
- Calorstat: A major European OEM supplier, but less commonly discussed in the US market for classic GM vehicles.
Common Ordering Mistake
The single biggest mistake is ordering the wrong temperature rating. The 1973-1988 Buick Regal used many different V6 and V8 engines, each with a specific thermostat requirement (typically 180°F or 195°F for stock applications). Always verify the correct temperature for your engine before purchasing.
Cost of a New Thermostat
| Part Type | Price Range |
|---|---|
| New Aftermarket Thermostat | $7.12 - $56.13 |
| New OEM (ACDelco) Thermostat | $10 - $30 |
| Shop Labor for Installation | $75 - $150 |
Frequently Asked Questions
What temperature thermostat do I need for my Regal?
It depends on your engine. Most stock V6 and V8 engines from this era use a 195°F thermostat for optimal efficiency and emissions. Performance-built engines may use a 180°F or even a 160°F thermostat. Always check your vehicle's service manual or a reliable parts catalog for the correct specification.
Is a "fail-safe" thermostat a good idea?
A fail-safe thermostat is designed to lock in the open position if it fails. This prevents a catastrophic overheating situation. However, it then creates the symptoms of a stuck-open thermostat (no heat, poor performance) and must be replaced. Some mechanics prefer standard, high-quality thermostats, arguing that fail-safe designs can sometimes fail prematurely.
Do I need to replace the gasket too?
Yes. Never reuse the old thermostat housing gasket. A new gasket is essential to prevent coolant leaks. Most new thermostats come with a new gasket, but if not, be sure to purchase one separately.
Is it hard to replace the thermostat myself?
On a 1973-1988 Buick Regal, this is generally an easy job for a DIYer. The thermostat is usually located at the front of the engine where the top radiator hose connects. The process involves draining some coolant, removing two bolts, swapping the part, and refilling.
Technical Specifications
The correct thermostat and part number vary significantly based on the specific engine (e.g., 3.8L V6, 5.0L V8, 5.7L V8) and year of your Buick Regal. Always verify the exact part and temperature rating (commonly 180°F or 195°F) for your vehicle before purchasing. The physical size is also critical; most thermostats for this application are around 54mm in diameter.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.