A replacement engine must have a dependable cooling system to maintain safe operating temperatures and protect important internal components. One area buyers should not overlook is the condition of the coolant passages inside the cylinder head. Corrosion, deposits, and internal blockages can restrict coolant circulation and contribute to overheating. When comparing used engines for sa... https://usedenginepart.com/how-cylinder-head-coolant-passage-condition-helps-buyers-assess-used-engine-overheating-risks-in-2026/