Engine cooling system - liquid, closed, with forced circulation of coolant by a centrifugal pump

Coolant is supplied to the cooling jacket of the cylinder block.

The low-freezing liquid OZH-40 Lena, TOSOL-A40M or water are used as a coolant.

At ambient temperature below minus 40 °С, it is necessary to use OZH-65 Lena, TOSOL-A65M.

For normal engine operation, the temperature of the coolant must be maintained within 70–90 °C.

This is done by a thermostat that automatically controls the amount of fluid passing through the radiator, and louvers that control the amount of air that cools the radiator.

In cold weather, the cooling system must be protected with an insulating cover with a flap valve.

The temperature of the coolant is controlled by a temperature gauge located on the instrument panel and connected by an electrical wire to a temperature sensor screwed into the thermostat housing.

In addition, overheating of the coolant is signaled by a lamp with a red light filter installed on the instrument panel and connected by an electrical wire to a temperature sensor screwed into the upper radiator tank.

The signal lamp lights up when the coolant reaches a temperature of 91–98 °C.

The reasons for overheating can be: low fluid level in the radiator, weak fan belt tension, movement with closed blinds and a closed valve of the insulating cover.

If the warning light comes on, the cause of overheating must be immediately identified and eliminated.

Pump 421.1307010–01 is a centrifugal type, driven by a V-belt from the crankshaft pulley.

The design of the pump uses a ball-roller bearing, made integral with the pump shaft.

The bearing has special seals that ensure that the lubricant incorporated during manufacture is retained. The bearing does not require additional lubrication during operation.

Thermostat – with solid filling, placed in the body.

Operating the engine without a thermostat is unacceptable, because when the thermostat is removed, the main fluid flow will circulate in a small circle of the cooling system, bypassing the radiator, which will lead to engine overheating.

When servicing the cooling system of the Model 414 and Model 4178 (before 1999* release), their design features must be taken into account: *

By the end of 1999, it is planned to completely switch to the production of model 4178 engines with the supply of coolant to the cooling jacket of the cylinder block - the coolant is supplied to the cylinder head;

- two ball bearings are installed in the pump (21–1307010–52) of the cooling system. Lubricate the bearings according to the lubrication table.

Lubricate the bearings through the grease fitting until grease comes out of the control hole. Remove excess grease, as it can get on the fan belt and disable it;

– the coolant temperature control sensor is screwed into the cavity of the cooling system pump;

– the thermostat is installed in the outlet pipe.

Avoid getting coolant into the oil when removing the head or for other reasons, as this causes the oil to gum, which can lead to coking and loss of mobility of the pushers, resin deposits and blocking of small holes that supply lubricant to the rubbing surfaces.</p >

Maintenance of the cooling system consists in removing scale and sediment from it, adjusting the tension of the fan belt, and flushing the radiator from the outside.

After every three years or every 60,000 km (whichever comes first), flush the cooling system and replace the coolant with new.

Flush the cooling system as follows:

- fill the system with clean water, start the engine, let it run until it warms up, with the engine idling, drain the water and turn off the engine;

- after the engine has cooled down, repeat the above operation.

Flushing the cooling system

Fig. 1. Flushing the cooling system

In case of significant scale and sediment deposits, remove them from the cooling system by washing with a strong jet of clean water.

Flush the engine separately from the radiator (Fig. 1) so that rust, scale and sediment from the engine cooling jacket do not clog the radiator.

Before flushing the engine, in this case, remove the thermostat and disconnect the hoses from the radiator.

For better cleaning of the cylinder block cooling jacket, unscrew the drain cock from the cylinder block together withfitting.

Rinse the cooling jacket until the water coming out of the engine is clean. Do not use alkaline solutions to flush the cooling jacket, as they corrode the cylinder head and block.

Rinse the radiator with the plug closed, supplying water first to the upper pipe to remove sediment from the lower tank first, and then to the lower pipe.

Rinse until the water coming out of the top tank is clean. At the same time, flush with a jet of water and blow compressed air through the core of the radiator.

If there is significant scale buildup in the radiator tubes, do the following:

1. Remove the radiator from the car and fill it with a 10% sodium hydroxide (caustic soda) solution, preheated to a temperature of 90 ° C.

2. After 30 minutes, drain the solution from the radiator.

3. Flush the radiator with hot water in the direction opposite to the circulation of the coolant in the engine (see Fig. 1) for 30–40 minutes under a pressure of no more than 49 kPa (0.5 kgf / cm 2).

Check fan belt tension

Fig. 2. Checking fan belt tension

Adjust the fan belt tension by turning the alternator.

The normal deflection of the belt should be 8–14 mm when pressed with a force of approximately 4 kgf (Fig. 2).

Check the operation of the thermostat at the same time as flushing the cooling system, as well as in case of systematic overheating of the engine (if the power and ignition systems are working properly).

To check, place the thermostat together with a thermometer in a vessel with water heated to a temperature of 90-100 ° C.

Then, while gradually cooling the water, watch the temperature of the beginning (80±2) °C and the end of closing (70±2) °C of the thermostat valve.

Replace the defective thermostat with a new one.

When checking the thermostat, pay attention to the cleanliness of the valve plate. Remove scale and dirt from the surface of the thermostat with a wooden spatula, then rinse in water.

You can also check that the thermostat is working by heating the inlet pipe of the upper radiator tank when the engine is warming up.

If the thermostat is faulty, the pipe warms up immediately after the engine is started, if the thermostat is in good condition, after the water temperature in the block reaches 60-70 ° C (according to the coolant temperature gauge on the instrument panel).

Check the blinds for completeness of opening with the drive handle fully pushed in.

If the blinds do not open fully, then adjust them as follows:

1. Loosen the screw securing the drive rod in the swivel joint of the lever located on the blinds.

2. Fully open the blinds by turning the drive lever counterclockwise.

3. Slide the blinds drive handle all the way in.

4. Secure the drive link in this position in the swivel joint of the lever.

5. Close and open the blinds several times in a row, then check the full opening of the shutters of the blinds with the handle pushed in to the full and their full closing with the handle pulled out.

If at the same time the drive handle moves with great effort, lubricate the axles of the blinds and the rod.

Lubricate the leaf axles with engine oil, and the rod, after removing it from the shell, with Litol-24 grease.

The linkage can be lubricated with a light penetrating lubricant consisting of 60% colloidal graphite concentrate in mineral oil and 40% white spirit. Apply lubricant to the rod shell.

Fan drive clutch

Fig. 3. Fan drive clutch

Model 4218 and 4178 engines can be equipped with a viscous fan drive clutch (fig. 3) to reduce fuel consumption, reduce fan noise, and also help warm up a cold engine and maintain engine thermal conditions within optimal limits.

The outer surface of the coupling must be kept clean to ensure the removal of heat generated during the operation of the coupling and the normal operation of the bimetallic valve spring.

The clutch is switched on and off automatically.

If the clutch stops working, disconnect the clutch from the hub (the connection of the clutch with the hub has a left-hand thread), remove the fan, unscrew the two fan mounting studs from the clutch housing, drain the working fluid through the holes of the studs and thoroughly rinse the inside of the clutch with gasoline.

Let the gasoline drain completely, then pour 40 g of polymethylsiloxane fluid PMS-10000 TU 6-02-737-78 into the coupling through one of the holes. The second hole must be open for air to escape.

After that, wrap the studs into the housing, secure the fan and install the coupling on the coolant pump pulley hub.

Drain the engine cooling system through two taps. One of them is located on the lower radiator tank, the other - on the cylinder block. When draining, remove the radiator cap.