Quicksilver 8M0174561 Thermostat Housing 140°F Mercury Verado 135-400HP

The Quicksilver 8M0174561 is an OEM replacement thermostat housing with integrated 140°F thermostat, designed for select Mercury 4-stroke Verado outboard engines ranging from 135 to 400 horsepower. As a genuine Quicksilver part, it restores precise engine temperature regulation and ensures your outboard's cooling system operates at factory specifications.

The housing is constructed from a corrosion-resistant, high-temperature molded composite material engineered for extended service life in harsh marine environments. A 90-degree bend on the outflow side and a built-in stainless steel thermostat are integrated directly into the housing assembly, simplifying the replacement process and maintaining reliable coolant flow management.

This kit replaces previous OEM part number 892864T04 and is compatible with the following Mercury Verado engine configurations:

• 135–200HP (4-cylinder) — Serial No. 1B311420 and above
• 200–300HP (6-cylinder, prior to Gen V) — Serial No. 1B390143 to 2B144127
• 200–300HP (6-cylinder, Gen V) — Serial No. 2B144123 and above
• 350–400HP (6-cylinder) — All serial numbers

What's Included:

• Thermostat housing
• Internal stainless steel thermostat

Note: Seals, gaskets, clamps, and attaching hardware are sold separately. Always replace all housing seals, gaskets, and clamps when servicing to ensure proper cooling system function. Consult your engine's service manual for complete installation guidance.