Sierra 143 Degree Marine Thermostat, Replaces 436195, Part Number 18-1507

The Sierra 18-1507 is a 143 degree F marine engine thermostat, engineered as a direct replacement for outboard and sterndrive cooling systems that call for a 143 degree opening temperature. The thermostat regulates coolant flow through the engine block, staying closed until the powerhead reaches its designed operating temperature and then opening to allow water flow to the cooling passages. Maintaining the correct opening temperature is critical for marine engines: running too cool can lead to poor combustion and increased wear, while a failed or stuck thermostat can cause overheating and serious engine damage.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-1507
• Product Type: Thermostat
• Temperature Rating: 143 degrees F
• Weight: 0.01 pounds
• Unit Count: 1
• UPC: 808282167127
• OEM Cross Reference: 436195

Fitment

Designed as a direct fit for engines specifying a 143 degree F opening thermostat.

Replaces (OEM)

• 436195

Frequently Asked Questions

What temperature does the Sierra 18-1507 thermostat open at? The Sierra 18-1507 opens at 143 degrees F, which is the rated temperature stamped for this part.

What OEM part number does 18-1507 replace? It replaces OEM number 436195, so it can be used as a direct substitute for that original thermostat.

How much does this thermostat weigh? The Sierra 18-1507 thermostat weighs 0.01 pounds.

How many thermostats come in a package? Each Sierra 18-1507 package contains a single thermostat unit.

Is the Sierra 18-1507 a genuine Sierra part or aftermarket? It is a Sierra-branded thermostat manufactured under Sierra's own part number, 18-1507.

What is the UPC for this part? The Sierra 18-1507 thermostat carries UPC 808282167127.

What happens if a marine thermostat like the 18-1507 fails? A stuck or failed thermostat can prevent proper coolant flow, leading to engine overheating or, if stuck open, slower warm-up and reduced efficiency, which is why matching the correct 143 degree rating for part 18-1507 matters.

Can I use a different temperature rated thermostat instead of the 143 degree 18-1507? The 18-1507 is specifically rated at 143 degrees F, and using a different opening temperature than the engine manufacturer specifies is not recommended since it changes engine warm-up and operating temperature behavior.

Does the 18-1507 include a gasket or seal? The listing for part 18-1507 covers the thermostat itself; a separate thermostat seal (such as Sierra 18-1734 or 18-1506) may be needed depending on the engine application.

How do I know if 18-1507 is the right thermostat for my engine? Confirm your engine calls for a 143 degree F thermostat or originally used OEM part 436195, since Sierra 18-1507 is built to that specification.