Maintain flawless engine cooling system circulation and stop coolant leaks with this 100% Toyota Original Thermostat Housing Top Water Outlet (Part Number: 16331-54112). Engineered as a Toyota original direct mechanical replacement under-hood cooling component, this premium coolant outlet neck sits perfectly over your thermostat assembly to guide hot engine coolant safely out to your upper radiator hose.

Unlike cheap aftermarket housings that use low-grade aluminum castings which warp under sudden temperature shifts, corrode prematurely from water contact, or develop hairline leaks along the bolt flanges, this Toyota original component is precision-cast from heavy-duty structural alloy. It ensures a perfectly flat, flush mating surface that holds a tight gasket seal, protecting your hard-working diesel engine from catastrophic overheating.

This top thermostat housing cover fits perfectly on the engine block cooling system of the following vehicle models:

A cracked, heavily pitted, or warped thermostat housing top is a major mechanical hazard. If your engine coolant constantly seeps or sprays out of a weak connection, it will drain your radiator system quickly, leading to blown head gaskets, cracked cylinder heads, and eventual total engine failure that costs thousands to fix. Furthermore, generic aftermarket cast water necks often have minor microscopic misalignments along the mounting rail, causing coolant to weep past the gasket even after a fresh installation. This Toyota original 16331-54112 thermostat housing top guarantees maximum structural strength, perfect alignment tightness, and absolute cooling system safety.