Cooling
Coolant Types — What You Need to Know for Your Van
Using the wrong coolant type can cause corrosion, sludge, and overheating. Always use the manufacturer-recommended specification for your van.
Coolant is not just antifreeze — it also contains corrosion inhibitors, lubricants, and anti-foaming agents. There are several types: IAT (traditional green/blue), OAT (orange/red, long-life), and HOAT (hybrid, often yellow). Mixing incompatible types can cause a chemical reaction that forms thick sludge, blocking the radiator and heater matrix. Most modern vans specify OAT long-life coolant with a 5-year or 100,000-mile change interval. Even long-life coolant degrades over time and loses its protective properties. Using distilled or deionised water for mixing prevents mineral deposits that can block cooling passages.
Key takeaways
- Mixing incompatible coolant types can form sludge that blocks the cooling system
- Long-life OAT coolant lasts up to 5 years but still needs replacement eventually
- Always check the manufacturer specification — using the wrong type risks engine damage
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