🔍 Key Concepts

• Corrosion control in closed freshwater cooling systems • Typical pH range for treated engine coolant (with corrosion inhibitors) • Effects of too acidic vs too alkaline water on engine metals and seals

💭 Think About

• Think about what happens to engine metals (like iron, copper, aluminum) if the cooling water is slightly acidic versus slightly alkaline. • Consider what normal, untreated fresh water pH is, and then how coolant additives (like corrosion inhibitors) usually shift that pH. • Ask yourself which pH range would best balance corrosion protection without attacking rubber seals, gaskets, or forming heavy scale.

✅ Before You Answer

• Compare each option to the neutral pH of 7.0 and decide if it is slightly alkaline, strongly alkaline, or acidic. • Eliminate any ranges that would be highly corrosive to metals or damaging to rubber components. • Recall manufacturer recommendations: most diesel engine cooling systems use inhibited, slightly alkaline water rather than strongly acidic or highly caustic solutions.