Page 17 - Demo

Page 17.Alvis Three Litre Shop Manual - T.A. 21 and T.C. 21ENGINE COOLING SYSTEMThe cooling water is circulated by an impeller type water pump bolted to the front face of the cylinder block.Having passed through the radiator, the water is led to an aperture in the cylinder block which is connected to the inlet side of the pump by a cored passage inside the cylinder block. The pump impeller forces the relatively cool water along an internal copper tube in the cylinder head which directs it on to the exhaust valve seats and sparking plug bosses through suitably spaced apertures. The heated water returns to the radiator header tank through a thermostatically controlled valve in the front of the cylinder head. A number of cored holes connect the cylinder block water jacket to the cylinder head and circulation inside the block is by thermosiphon action. A spring-loaded relief valve is incorporated in the radiator header tank.ThermostatA thermostatically controlled valve is incorporated in the system to by-pass the radiator until the engine has reached its working temperature, thus ensuring rapid warming up from cold. This valve restricts the outlet from the cylinder head to the radiator header tank when the engine is cold, forcing the water back to the inlet side of the pump through a drilled hole connecting the cylinder block water jacket to the pump inlet passage. The thermostat is entirely automatic in operation and requires no attention whatsoever. RRaadiat iator Watater LLevvelThe cooling system has a total capacity of approximately 3 gallons (13.6 litres). It is important that the level of the water in the radiator is inspected regularly and always maintained to within about 1/2 in. of the bottom of the filler neck.EEngi gine LLububricati ication Mai ainttenaancceDAILY. %u2013 Check the oil level.AFTER THE FIRST 500 MILES (800 K.M.). %u2013 Change the engine oil.EVERY 2,000 MILES (3,200 K.M.). %u2013 Change the engine oil.EVERY 10,000 MILES (16,000 K.M.). %u2013 Clean oil filter.oil pump body allowing the filter to be removed. The filter can then be cleaned in petrol, after which the sump may be replaced, a little jointing compound being applied to the sump face. When replacing the sump the rear bolts must be finally tightened before the others in order to obtain an oil-tight joint at the rear face.OOiil RReliieff VaalvveThe oil relief valve is situated on the off-side of the engine directly below the distributor boss or almost in line with the dipstick.The oil relief valve is spring loaded and is held in position by a hexagon domed nut.If the oil pressure is observed to drop, the dome nut should be unscrewed, and the relief valve removed; the seating can then be inspected for possible faults. Invariably the cause of a drop in oil pressure is due to a foreign body becoming lodged on the oil relief valve seating. To overcome this matter the engine should be allowed to idle with the relief valve removed so that the flow of oil will remove whatever foreign body is likely to be present.When the engine has run for a sufficient period to flush the seating, etc. (about 15 seconds), the oil relief valve, spring, and dome nut can be refitted. The engine should now be restarted and a normal pressure observed on the oil pressure gauge.