Checking the hoses and connections of the Renault Sandero cooling system

Cause of malfunction

Remedy

The engine gets very hot

Low coolant level in expansion tank

Add coolant

Faulty thermostat (valve stuck closed)

Replace thermostat

Faulty water pump

Check pump and replace if defective

Radiator core clogged with dirt and insects

Radiator tubes, hoses and engine cooling jacket clogged with scale and sludge

Wash the outside of the radiator core

Flush the cooling system and fill with fresh coolant

The electric fan does not turn on due to an open circuit or failure of the sensor, relay or fan motor

Check and repair electrical circuits. Replace sensor, relay or fan assembly if necessary

Damage to the valve in the plug of the expansion tank (permanently open, due to which the system is under atmospheric pressure)

Replace expansion tank cap

The engine overheats, cold air comes out of the heater

Excessive drop in coolant level due to a leak or damage to the cylinder head gasket, causing vapor lock in the engine water jacket

Repair any coolant leak. Replace damaged cylinder head gasket

The engine does not warm up to operating temperature for a long time,  the thermal regime during movement is unstable

Faulty thermostat (valve stuck open)

Replace thermostat

Constant decrease in coolant level in the expansion tank

Leaky radiator Leaky expansion tank

Replace radiator Replace expansion tank

Coolant leaks through leaky pipe and hose connections

Tighten hose clamps

Damaged water pump seal

Set the water pump to sealants

The cylinder head bolts are not tightened enough (during a long stop on a cold engine, coolant leaks at the junction of the block head with the cylinder block; in addition, traces of coolant may appear in the engine oil)

Tighten the cylinder head bolts to the required torque

Coolant leakage through the cylinder block water jacket plugs

Replace the damaged gasket, restore the tightness of the plugs

Leaky heating radiator

Replace heating radiator