Checking fluid levels (BMW 5 Series E28)

Weekly or every 400 km (whichever comes first).

The following procedures are used to check the liquid level every 400 km or weekly. Other fluid level checks can be described later in the Sections on specific maintenance procedures. Regardless of the scheduled check intervals, do not allow fluid to leak under the vehicle, as such leaks indicate a malfunction that should be corrected immediately.

Fluids are an integral part of the lubrication, cooling, braking and windshield washer systems. Due to the gradual consumption and/or contamination of fluids during normal vehicle operation, they should be replaced periodically. See the section Types of Lubricants and Fluids Used in Table of sizes and adjustment data at the end of the Manual before adding fluid to any of the listed components.

Whenever checking the fluid level, the vehicle must be on a level surface.

Engine oil

The engine oil level is checked using the dipstick located on the side of the engine (refer to the engine compartment illustrations provided in this Chapter to determine its location). The dipstick passes through the metal tube downwards, reaching the bottom of the engine oil pan.

The engine oil level is measured before starting the engine or at least 15 minutes after turning it off.

If you start measuring the engine oil level immediately after turning off the engine, some oil will remain in the upper part of the engine, which will significantly affect the accuracy of the dipstick readings.

1. Remove the dipstick from the tube and wipe its blade dry with a clean rag or paper towel. Insert the dipstick all the way back into the tube and remove it again. The height of the oil-wetted section of the blade will correspond to the oil level in the engine. This level should be between the two marks on the dipstick.



2. It takes one liter of oil to raise the oil level from the minimum mark on the dipstick to the maximum. Do not allow the level to fall below the minimum mark, as oil starvation can cause engine damage. On the other hand, overfilling the engine with oil (topping up above the maximum mark) may cause spark plugs to become oily, oil leaks or seals to fail.



5. To add oil, unscrew the filler cap located on the cylinder head cover.



4. After adding oil, wait a few minutes for the oil level to stabilize, then remove the dipstick and check the level again. Add more oil if necessary. Close the filler cap and tighten it by hand.

Checking the oil level is an important preventive procedure. A constant drop in the oil level indicates either leaks through damaged seals or loose connections, or oil is burning out (internal leaks through worn piston rings or through valve guides). In addition, you should pay attention to the condition of the oil itself. If the oil is milky or if you can see drops of water in it, this indicates a possible leak in the cylinder head gasket or a crack in the head or cylinder block. In this case, the engine should be repaired immediately. Each time you measure the oil level, before wiping the dipstick blade, run your thumb and forefinger over it. If you find dirt or metal particles stuck to the dipstick, the oil should be replaced (see section Changing engine oil and oil filter).

Engine cooler

Do not allow antifreeze to come into contact with your skin or the painted surfaces of your vehicle. If this does happen, rinse off the antifreeze immediately with plenty of water. Antifreeze is extremely toxic if ingested. Never leave it unattended in an open container or spilled on the floor; children or animals may be attracted to its sweet smell and may drink it. Arrange with local authorities for disposal of used antifreeze.

All vehicles covered in this manual are equipped with a positive pressure, compensating cooling system. On most models, the white plastic expansion tank is located in the engine compartment and is connected to the radiator by a hose. As the engine warms up during operation, the expanding coolant fills the tank. As the engine cools, the coolant automatically flows back into the cooling system, which ensures that its level is maintained at a constant value.

Check the coolant level in the reservoir regularly. Add a 40%/60% mixture of ethylene glycol antifreeze and water.



1. On some models the expansion tank is attached to the radiator - make sure the fluid level remains at or near the FULL mark (indicated by the arrow).





2. On other models the expansion tank is located on the side of the engine compartment - remove the cap and add coolant.



3. On some models, the expansion tank is located on the bulkhead.



Adding antifreeze mixture.

Do not remove the expansion tank filler cap or radiator cap to check the coolant level until the engine has cooled down completely! The level in the reservoir fluctuates depending on the engine temperature. When the engine is cold, the coolant level should be above the LOW mark on the reservoir. As the engine warms up, the level should approach the FULL mark. If this is not the case, allow the engine to cool down and then remove the cap from the reservoir.

4. Run the vehicle and measure the coolant level again. If only a small amount of coolant needs to be added to the required level, you can use clean water to do this. However, frequent additions of water will dilute the antifreeze. To ensure the correct ratio of antifreeze to water, always add the required mixture to the required level.

5. If the coolant level drops regularly, there may be a leak in the system. Inspect the radiator, hoses, filler cap, drain plugs and water pump (see section Draining, flushing and filling the cooling system). If no leaks are found, have the expansion tank cap and radiator checked for leaks at your BMW dealer service department.

6. If you need to remove the cover, wait until the engine has cooled down completely, then wrap a thick rag around the cover and unscrew it to the first stop. If steam or coolant starts escaping from under the cover, allow the engine to cool down a little more before removing the cover.

7. It is also necessary to check the condition of the cooler. It should be relatively clean. If the liquid is brown or rusty, it must be drained, the system flushed and filled with a new mixture. Even if the cooler looks normal, the corrosion inhibitors in its composition lose their effectiveness over time, so it should be replaced at certain intervals.

Brake and clutch fluid

Brake fluid can cause eye damage and damage the painted surfaces of your vehicle, so be extremely careful when handling it. Do not use brake fluid that has been open for a long time or that is more than one year old. Brake fluid tends to absorb moisture from the air, which can lead to a dangerous loss of braking efficiency. Use only the recommended type of brake fluid. Mixing different types of fluid (such as DOT 3 or 4 and DOT 5) may result in failure of the braking system.

The brake master cylinder is located in the rear left corner of the engine compartment. Clutch cylinder (on models with manual transmission) located on the right side.



1. To check the clutch fluid level, look into the translucent reservoir. The level should be near the lip on the reservoir. If it is lower, remove the cap and add the recommended fluid.



2. The brake fluid level is also checked visually, using the marks on the plastic reservoir mounted on the master cylinder. The fluid level should be between the MAX and MIN marks. If the level is below the acceptable level, first wipe the top of the reservoir and the cap with a clean rag to prevent dirt from getting into the system after removing the cap. Top up to the required level with the recommended fluid, but do not overfill.

3. While the reservoir cap is removed, check the fluid and master cylinder reservoir for contamination. If there are rust particles, dirt or water droplets, the fluid in the system should be drained and replaced with new fluid.

4. After filling the reservoir to the required level, make sure the cap is installed evenly to avoid liquid leakage and/or dirt ingress.

5. The fluid level in the master cylinder will drop slightly as the brake pads wear. There is no need to top it up as long as the level remains near the MIN mark; it will rise after replacing the pads. A very low level may indicate worn brake pads. Check them for wear (see section Checking the brake system).

6. If the brake fluid level drops continuously, immediately check the entire system for leaks. Inspect the brake lines, hoses and fittings, together with the calipers, wheel cylinders and master cylinder (see section Checking the brake system).

7. If, when checking the fluid level, one or both reservoirs are found to be empty or nearly empty, the brake or clutch system should be checked for leaks and bled (see Chapters Clutch and Brake system).

Windshield washer fluid

The windshield washer fluid is located in a plastic reservoir in the right front corner of the engine compartment.

In temperate climates, the system can be filled with plain water, but the reservoir should be filled no more than two-thirds full to allow for expansion when the water freezes. In cold climates, use a special windshield washer antifreeze that lowers the freezing point of the fluid, which can be purchased at any auto accessory store. It is usually sold in concentrated or ready-mixed form. If you buy concentrated antifreeze, mix it with water according to the manufacturer's instructions on the package.

Do not use antifreeze in the cooling system - it will damage the painted surfaces of the car.