Sierra 118-3550 Marine Thermostat 140 Degree for MerCruiser

The Sierra 118-3550 is a premium marine thermostat designed for MerCruiser stern drives and select Chrysler/Force/US Marine engines. Engineered to meet or exceed OEM specifications, this thermostat features a 140-degree Fahrenheit temperature rating and is constructed from durable copper and brass materials to withstand harsh marine environments.

Key Features:

• 140°F opening temperature rating for optimal engine cooling performance
• Copper and brass construction for corrosion resistance and reliability
• Direct replacement for Mercury/MerCruiser and Chrysler/Force applications
• Designed specifically for raw water cooled marine engines
• Meets or exceeds original equipment manufacturer standards

Application:

• MerCruiser 120/2.5L (s/n 2324347 & up) with cast iron exhaust manifolds
• MerCruiser 140-3.0L (s/n 0L340999 & below)
• MerCruiser 165 GM 250 I/L6 engines
• Various MerCruiser 2.5L and 3.0L GM engines from 1982-1998

OEM Cross-References: Replaces Mercury/MerCruiser 59078, 59078A1, 59078B; Chrysler/Force/US Marine F84068, F84068-1, F84068-2, F85068-2; GLM 13020; and Mallory 9-43020. This ensures proper fit and function across multiple marine engine platforms.

Backed by Sierra's industry-leading warranty, this thermostat is designed to provide reliable temperature regulation for the useful life of the product. Sierra has been a trusted name in marine replacement parts for over 50 years, delivering high-quality components engineered to meet today's demanding marine applications.