- Jack and stand-up goats.
- Large slotted screwdriver.
- A set of ring or socket wrenches.
- Coolant drain container.
The following parts are required for replacement:
- To replenish the coolant level, even in the warm season, use only a mixture of soft clean water and antifreeze. To avoid deposits, it is best to use distilled water. Use only nitrite-free and ammonium-free antifreeze approved by BMW (permit for operation must be on the container).
Attention: In order to be able to continue the trip, you can also, especially in summer, drink clean water. However, after this, it is necessary to bring the concentration of antifreeze in the coolant to the required level as soon as possible.
- The drain plug in the cylinder block requires an A14x18 aluminum o-ring.
Filling volume of the cooling system
Coolant drain
Turn on the heater to maximum power using the switch in the passenger compartment.
First turn the cap of the cooling system slightly to the left to relieve excess pressure. After that, unscrew the cover to the end and remove.
Caution: Do not open expansion tank cap when engine is hot. Risk of burns from steam! The cooling system is under pressure! Open the cover only when the coolant temperature is below +60°C. Before opening the lid, put a cloth on it.
Raise the car in front. Remove lower engine cover.
Place a clean container under the radiator and release the drain plug -arrow- from below the radiator. To unscrew, use a large slotted screwdriver or a coin.
Place a container under the engine and remove the drain plug -arrow- on the cylinder block. The plug is located directly under the exhaust manifold.
Drain the coolant completely.
Caution: Coolant is poisonous and must not be splashed out and disposed of with household waste. The administration of cities and districts should inform about where the nearest collection point for special waste is located.
Fit the drain plug of the cylinder block with a new gasket and tighten to 25 Nm.
The radiator drain plug is easy to tighten. To do this, insert a coin into the slot of the cork and tighten the cork firmly by hand.
Filling the cooling system
Pour fresh coolant into the expansion tank to the brim.
Car models 520i, 523i, 528i
Open the bleeder plug -arrow- at the top of the radiator, next to the expansion tank, and wait until coolant flows through the hole without air bubbles.
Unscrew the bleed screw -arrow- on the coolant line in the area of the oil filter and wait until coolant flows through the opening without air bubbles.
Close the air bleed plugs and top up the coolant level in the expansion tank.
Model 525tda: Bleeding is automatic through the top hose to the freestanding expansion tank, so there are no bleed plugs.
Close expansion tank cap. Do not warm up the engine with the expansion tank cap open, as this may cause it to fail.
Start the engine, turn the heater switch to the WARM position and warm up the engine. While jerking the accelerator pedal, maintain the engine speed above 2500 rpm. The air leaving the cooling system helps to lower the coolant level to approximately the maximum level mark on the expansion tank.
Switch off the ignition.
Caution: Top up any insufficient coolant level only after the engine has cooled down. Otherwise, there is a risk of steam burns when opening the expansion tank cap!
When the engine is cold, top up the coolant level up to the MAX mark on the expansion tank, see illustrations in chapter "Checking the coolant level".
Open the bleeder plugs again and make sure that coolant flows out of the holes without air bubbles. Close the radiator cap and tighten the air bleed plugs.
Check the cooling system, especially the hose connections, as well as the drain plugs and the coolant pump for leaks.