Excerpt from Chapter 13 – Increasing Reliability and Safety

Making Sure the Engine Stays Cool

Like most standard engines, the MINI engines are equipped from the factory with synthetic rubber radiator and heater hoses. With some attention to make sure they're not wearing out, these hoses are fine in normal use. However, they will deteriorate over time, and wear out faster if the car is driven aggressively. Unfortunately, since the deterioration is caused by chemical reaction between the coolant and the metal in the engine, it occurs from the inside out. As a result, this wear is generally not apparent on visual inspection. You can spot potential failure by squeezing the hoses. If they seem soft, they're prone to failure, which can allow the engine to overheat, with potentailly catastrophic effects.

The alternative is to fit the car with silicone hoses, which are easy to install, and look good in the engine compartment. They advantage of silicone hoses is that they are not prone to electrolytic deterioration like the stock hoses, which is why they're the type that is generally preferred by racing competitors. A set of hoses, which will pretty much last the lifetime of the engine, will cost less than $250.