Magazine · Car
Oil stain under the car: where does it come from?
A dark spot on the parking space is a warning sign, but no reason to panic. We sort out the causes.
To the causes
What this is about
Look first, then judge
Not every puddle under the car is motor oil. Water from the air conditioning is harmless, dark oily dripping by contrast needs checking. The colour and place of the stain give first clues.
A single small drop is judged differently from a growing pool.
Common sources
- Drain plug or filter: after an oil change sometimes not fully tight, one of the most common causes.
- Gaskets: valve cover or other gaskets can become leaky over time.
- Different fluids: gear oil, power-steering fluid or coolant can drip too, the colour helps to tell them apart.
- Water is harmless: clear drops in summer are mostly condensation from the air conditioning.
Said honestly
An oil stain is a clue, not a verdict: often a small leak is behind it, sometimes just harmless water. What matters is to have the source checked before a drop turns into oil loss with engine damage. Put a piece of cardboard underneath and watch colour and amount, then off to the workshop. We give you the facts, the decision stays with you.
Sources and further reading
- Motor oil , Wikipedia