Black oil on the dipstick — is it a problem?

Black oil on the dipstick worries many drivers. In reality, oil darkening is often a natural sign of it doing its job, not a fault.

When is dark oil normal?

Good oil cleans the engine and binds contaminants, which is why it darkens over time. This happens especially quickly in diesels because of soot. Darkening alone doesn’t mean the oil has lost its properties.

When should you stay alert?

• The oil is thick, tarry or has lumps
• There’s a distinct burnt smell
• A milky, beige film is visible on the dipstick
• The oil is clearly past its change interval

A milky film is another story — it can indicate coolant getting in. See what milky oil means.

If you don’t know when the oil was last changed, it’s best to start with a fresh call-out change.