When should engine coolant be changed?

Most modern coolants last 4–5 years or 60,000 miles. Older silicate-based coolants need changing every 2 years.

Here's a quick, honest answer from a working UK mechanic — what causes it, what it costs to fix, and what to do next.

Can I top up with water? — In emergencies only. Always restore the correct concentration as soon as possible — too dilute means freezing in winter, no boiling point margin in summer.

How do I check coolant strength? — Hydrometer or refractometer. Most garages check as part of a service.

Bob's Mechanical Repairs — independent family-run garage in Birnam, Dunkeld, Perthshire. Call 01350 727 276 or email bob@bobsmechanicalrepairs.co.uk.