This blog, in addition to the usual maintenance details for classic mini cars, an attempt is made to explain the "whys" and "wherefores" of the various jobs.

Saturday, 17 October 2009

Descaling and Flushing Cooling System

At least once a year preferably in the autumn and in the spring if an anti-freezing compound is used the system should be drained, flushed-out and refilled. If the water does not flow freely from the radiator drain tap and from the tap on the side of the engine cylinder Wock (both are accessible from inside the engine compartment) the openings should be probed with a piece of wire to dislodge any accumulated sediment or better still, unscrew and remove the taps. A hose should then be inserted in the filler neck and water allowed to flow through the system until clean water issues from the taps.

Before flushing the system it is an advantage to run the car for a day or two with a proprietary non-corrosive compound added to the cooling water. These compounds will remove any deposits of rust or scale which might be sealing minor leaks. If anti-freezing compound is used without descaling the system, there is a risk that its very "searching" action may find such weak spots, with possibly serious consequences if a leak should develop and continue undetected during the course of a lengthy run.

If an interior heater is fitted and the cooling system has been drained, make sure that the heater water-control tap is open when refilling the radiator. It is a good plan to slacken the clamp on the radiator end of the heater hose when a recirculatory type of heater is fitted, and to loosen the hose in order to dispel any air-lock, that may develop in the heater. Do

The "anti-smog" crankcase ventilation valve ,1tted to some models. The valve should be cleaned with methylated spirits at 12,000-mile intervals

1. Spring clip
2. Cover
3. Diaphragm
4. Spring
5. Control orifice

not tighten the clamp until water is flowing from this point and re-check the level in the header tank after the engine has been running for a few minutes.