See also:

Additives
Do not use any additives in the engine oil. This could damage the engine. ...

Brake fluid level
If you notice that the brake fluid level in the brake fluid reservoir has fallen to the MIN mark or less, check the brake system immediately for leaks. Also check the thickness of the brake ...

The windshield wipers are inoperative
The windshield wiper drive is malfunctioning. Select another wiper speed on the combination switch. Have the windshield wipers checked at a qualified specialist workshop. ...