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Electric Radiator Fans

A club member got in touch with me and raised the subject of fitting an electric fan onto a MK2. Some people think they are rather exotic devices however the majority of modern cars use them and particularly anything fitted with an east – west engine except the original Mini is almost guaranteed to be equipped with one. In addition have a look under the bonnet of your modern Commodore, Falcon and Magna and you will find an electric fan doing all of the cooling work.

It appears that one stumbling block for many people is the problem of fitting a sensor to turn the fan on when the engine is starting to overheat. There are several ways of handling this. One is to fit a sensor which plugs directly into the upper radiator hose. I consider this as rather crude and am more inclined to get a new thermostat outlet pipe and have a modern sensor fitted by machining an appropriate hole in the metal.

You might also investigate fitting a genuine Jaguar thermostatic fan switch as fitted to the E types and Series 1, 2&3 XJ among others. These were originally fitted in the cross flow radiator tank. Another access point is the original thermostat switch hole for the starting carbie which is generally redundant as most MK1/2 owners have modified their cars to use a dash mounted switch for the starting carbie function. You would have to do a bit of fettling to make a plate to carry a thermostatic switch

Another method is to fit a manual switch somewhere around the instrument panel. Anyone used to old Jaguars in hot weather will be monitoring the water temperature and it would be a simple thing to turn the fan on when it is starting to get hot. This is done in many competition saloon and sports cars which have had the mechanical fan blades removed. I am told that the only time the fan gets turned on is after the race and when returning slowly to the pits. Note that this switch needs to control a heavy current relay which will do the actual switching. Many modern electric radiator fans could be pulling upwards of about 50 amps while running and you would need an almighty big switch to handle that sort of load.

An electric radiator fan will consume about twice the output of the old Lucas generator. It may be worthwhile to consider fitting a modern alternator to carry the load particularly if you intend to drive the car frequently in traffic. The old Lucas generator has the further disadvantage of being “off line” while idling in traffic while the modern alternator will be on line and supplying power even when idling. I have alternators on two of my historic registered cars [a Mk1 and Mk2] and they are a boon in getting the battery charged quickly and giving better lights in traffic at night