Mini World – July 2019

[ Cooling system ]

60 July 2019 MiniWorld

Minis are cool cars but they sometimes get hot and bothered. Here

are some checks, tips and upgrades to make sure that yours stays cool.

Words and photos: Tim Mundy.

Check your Mini’s cooling system

R

egular maintenance of a Mini’s

cooling system is essential

for performance, e cient

running and preventing

serious problems. It will help to prevent

overheating issues, in both summer

and winter, and keep the heater working

at maximum e ciency in the colder

months. Early summer is the best time

to carry out maintenance as the Mini

will then be ready for the hotter months

and well prepared for the winter too.

Although not needed on such a

frequent basis, changing the coolant is

as important as changing the oil. In fact,

the majority of cooling system failures

are caused by lack of maintenance.

Overheating is bad enough but, if the

problem is not noticed in time (and

some Minis do not have a temperature

2

4

Make sure that the radiator cap is in good condition; it needs to

seal properly and release pressure at the correct poundage. Never

release the radiator cap when the engine is hot.

Standard mechanical cooling fans rarely give trouble but plastic

ones can occasionally crack or break. Check that the fan is fitted

the correct way round. It is marked ‘engine side’. If it is fitted the

wrong way round, the engine will overheat. You would be amazed

at how many feature cars and Minis at shows we see with the fan

incorrectly fitted! Check that OE electric fans, where fitted, cut in

with the engine running when the car has been stationary for a

while. If it does not, then suspect the fan sender in the radiator.

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3

If the temperature gauge is reading incorrectly it may simply be

down to a faulty sender. Replacement can be carried out without

draining the system if the engine is is cold, the coolant not

pressurised and you swap the parts quickly.

Make sure that your fan belt is in good condition, not

contaminated with oil and that it is correctly tensioned. Even

a slightly loose belt can slip and reduce the effectiveness of the

water pump and the dynamo or alternator too. Replace the belt

around every five years or sooner if required.

gauge), it can become much more

serious and lead to head gasket failure.

The cooling system deteriorates with

age and mileage. Old hoses perish and

burst, water pump seals and bearings

wear out and the radiator can become

blocked and corroded. The bypass

hose is often considered to be one of

the earlier Mini’s greatest problems

but, almost without exception, if it