We take great pleasure in introducing this technical bulletin, specifically dedicated to the BMW , Model C3 (E90) , Version 316 d (N7 D20 C) 85 Kw 116 Hp 1995 Cm3. The primary objective of this bulletin is to offer comprehensive guidelines and precise directives to aid you in efficiently managing maintenance and troubleshooting challenges.

SYMPTOMS:

Warning message on the instrument panel display (Check Control): ‘Coolant level too low’;

Engine coolant level too low.

The following symptom is observed in the workshop:

• The customer complains that they have had to refill the engine coolant tank several times.

NOTE: This bulletin applies only to vehicles equipped with one of the following engines:

• B37 Transverse / Longitudinal TU0.
• B47 Transverse / Longitudinal TU0
• B57 Longitudinal TU0.
• N47 Transverse / Longitudinal TU1.
• N57 Longitudinal TU1.

Warning message on the instrument panel display (Check Control): ‘Coolant level too low’;

Engine coolant level too low.

The following symptom is observed in the workshop:

• The customer complains that they have had to refill the engine coolant tank several times.

NOTE: This bulletin applies only to vehicles equipped with one of the following engines:

• B37 Transverse / Longitudinal TU0.
• B47 Transverse / Longitudinal TU0
• B57 Longitudinal TU0.
• N47 Transverse / Longitudinal TU1.
• N57 Longitudinal TU1.

POSSIBLE CAUSES :

There are different explanations for the cause of various situations with the list of symptoms mentioned in this bulletin.

• The cooling system is not sufficiently aerated and, as a result, there is not enough coolant in the engine cooling system.
• Defective coolant level sensor.
• Leak in engine cooling system.

For B57 engines:

• The coolant expansion tank never allows the coolant to reach the highest level due to various safety requirements, e.g. pedestrian protection.

This has a negative effect on the automatic ventilation cooling system. The ventilation system is set up to maintain a remaining air volume of more than 0.75 litres of the total volume. As a consequence, when the engine temperature to open the thermostat is reached, the coolant level is reduced by approx. 1 litre.

SOLUTION :

Repair procedure for B57 engine:

• Check that the warning message ‘Coolant level too low’ is recorded without coolant loss.
• Check the condition and operation of the coolant level sensor. The engine coolant level sensor must be activated from a coolant level below the minimum line. The coolant sensor must also be activated during dynamic driving.
• Check the condition of the coolant expansion tank.
• Replace the coolant expansion tank with a new one, if necessary.

Repair procedure for B37 / B47 / B57 / N47 / N57 engines:

Check the engine coolant for leaks according to the manufacturer’s instructions and check using a suitable tool with the appropriate specifications:

• Stop the engine.
• Measure the temperature of the exhaust gas recirculation pipe.
• Cool the vehicle if the tested temperature is above 50°C.
• Insert an endoscope.
• Remove the exhaust gas temperature sensor for exhaust gas recirculation.
• Unscrew the exhaust gas temperature sensor and count the number of turns required to unscrew it.
• Replace the exhaust gas temperature sensor for exhaust gas recirculation with a new one.
• Mount the sensor with the same number of turns as counted when unscrewing at a tightening torque of 21.7 Nm.
• Check that the electrical cable of the exhaust gas temperature sensor is not twisted.
• Check the condition of the exhaust gas recirculation cooler blades using an endoscope at the cooler outlet.
• Only remove the exhaust gas recirculation valve by loosening the fixing screws, omit the removal of the coolant pipes.
• Check the condition of the exhaust gas recirculation cooler blades using an endoscope at the cooler inlet.
• Replace the exhaust gas recirculation cooler with a new one if deposits or dirt residues have been found inside the cooler.
• Clean the exhaust gas recirculation circuit using a suitable tool.

See image 1:

A – Exhaust gas recirculation cooler.

See image 2:

A – Examples of clogged blades and example of blades in good condition.

IMAGE 1 :

IMAGE 2 :

Keep in mind that you have the option to consult Mecainfo‘s Technical Service Bulletin (TSB) for solutions already identified for frequently encountered issues.