ZH 
EN 
Every car shows problems large and small. But do all of them need money spent? Not at all: some apparent faults are nothing of the kind and need no repair, just a small adjustment.
1. Mist inside a new car’s headlamp
Many new owners notice it. Is the lamp faulty? No: there is a small vent in the rear cover that lets expanding hot air escape and keeps water out. Light misting clears quickly as air circulates or the lamp warms up. If water or mist persists, have a workshop investigate.
2. Black wheels
The cause is brake dust: friction between pad and disc produces carbon that bakes onto the rim. Wash the wheels more often and it stops building up.
3. Oil turning black soon after a change
This is the detergent-dispersant additive doing its job, plus normal oxidation in service. Change the oil and filter on schedule and do not worry about the colour.
4. Windows moving at different speeds
The glass channels dry out or collect dirt, so one side runs slower. Cleaning and lubricating the channel restores it.