Cooling system - Service Procedures

Checking the coolant level

The level should be approx. 4–5 cm (2") below the filler caps sealing edge. There must be an air space to allow for expansion of the coolant.

WARNING! Open the filler cap very carefully when the engine is warm. Hot steam or fluid can spray out.

An insufficient quantity of coolant can lead to poor circulation, which increases the risk of overheating, resulting in damage to the engine.Draining the coolant

Draining the coolant

Before draining the coolant, stop the engine, unscrew the filler cap.

See figure for the location of drain cocks and plugs. If a compressed air compressor is fitted there is also a drain cock on this. Unscrew the coolant filter, if fitted. Check carefully to make sure that all water runs out.

Filling the coolant

WARNING! Open the filler cap (or the venting cock) very carefully when the engine is hot. Steam or hot coolant can spray out as system pressure is lost.

NOTE! Check that the drain cock is closed and that the drain plugs are fitted and tightened before replenishing the cooling system.

Replenishing shall be carried out when the engine is stopped.

Open the venting cock, see fig above. Do not replenish too quickly to avoid air-locks in the system. The air shall be enable to flow out through the venting cock (TWD-engines) or filler opening.

If a heater is connected to the engine’s cooling system the heat control valve shall be opened and the system vented during replenishing.

Fill with coolant to approx. 5 cm (2") under the sealing surface of the filler cap. For coolants, see previous page.

IMPORTANT! The engine must not be started before the system is vented and completely replenished.

Start and run the engine warm. Open the venting cock for a moment after starting for the venting of any remaining air.

Check the coolant level and replenish if necessary. Replenish with the same mixture already used in the cooling system.

Coolant temperature too high

Too high coolant temperature can be caused by:

● Low coolant level, air in the system.

● Reduced air flow through the radiator, dirty radiator.

● Poor drive belt tension.

A=Drain cock/plug for coolant

B=Drain cock for coolant (TWD)

V=Venting cock (TWD)

● Blocked cooling system.

● Faulty thermostat.

● Faulty temperature gauge.

● Faulty setting of injection pump with regard to the preinjection angle.

● Faulty thermostically controlled fan (if fitted).

Coolant temperature too low

Too low coolant temperature can be caused by:

● Faulty thermostat

● Faulty temperature gauge.

Checking the temperature gauge

Remove the temperature sender. Connect the cables to the temperature gauge and immerse the sender in hot water. Compare the temperature gauge reading with that of a thermometer.

Charge air cooler insert, changing (TWD)

Drain the coolant.

Remove the front and rear flanges. 3

Loosen the bolts to flange, holding the drain cook and remove the drain cook.

4

Coolant loss

Loss of coolant can occur in two ways:

● Loss of coolant during running

● Loss of coolant after stopping a hot engine. Coolant loss during running can be due to leaks in the cooling system or air or combustion gases being pressed into the cooling system causing the coolant to be forced through the pressure valve. The fault can be in the compressed air compressor, it fitted, or leakage at the cylinder head gaskets.

Loss of coolant after stopping a hot engine is generally due to a faulty pressure valve (filler cap).

Remove the tube between the compressor housing and the charge air cooler.

5

Loosen the plastic pipe to the smoke limiter (if any).

6

Remove the bolts to the charge air cooler housing and carefully separate the housing from the intake manifold. Lift out the insert.

7

Remove the gaskets and clean the contact surfaces on the housing and the insert.