Coolant: when to change and why it matters

Coolant is not lifetime fluid. Over time it loses corrosion protection and stability, leading to overheating, internal corrosion and costly leaks.

What coolant actually does

• Keeps engine temperature stable
• Protects internal passages from rust
• Lubricates the water pump and seals
• Prevents freezing in winter and boiling in summer

When to change

• Typical interval: every 3–5 years (check manufacturer specs)
• If the color turns brown, cloudy or sludgy → change it
• After major cooling system repairs

What not to do

• Don’t mix coolants by color
• Don’t use tap water (minerals cause corrosion)
• Don’t ignore slow level loss — it often means a leak

Warning signs

• Temperature fluctuations under load
• Sweet smell inside the cabin (possible heater core leak)
• Crusty residue around hoses and joints