Car leaking oil: causes, urgency and repair costs
Fix soon
Check the dipstick and top up to the correct level. If the oil pressure light comes on, or you see smoke or smell burning oil, stop and switch off the engine.
Quick answer
Oil is amber when fresh and dark brown or black when old, feels slippery and is hard to wipe off your fingers. A few drips is not an emergency, but book a garage soon and keep the level topped up, because an engine that runs low on oil can be badly damaged. Common sources are a loose drain plug or oil filter, a worn valve cover or oil pan gasket, or, less often, the rear main seal.
Typical cost$240–$285£75–£500≈ €220–€260≈ A$360–A$430valve cover gasket, a common oil leak fix
How to tell oil from other fluids
Slide a sheet of white card under the engine overnight, or dab the drip with a paper towel.
| What you see | What it probably is | How urgent |
|---|---|---|
| Amber, brown or black, greasy, hard to wipe off, does not evaporate | Engine oil | Get it checked soon |
| Green, yellow, pink, orange or blue, sweet smell | Coolant | Get it checked soon |
| Red or reddish-brown, toward the front or middle | Transmission or power steering fluid | Get it checked soon |
| Clear, no smell, under the front after using the A/C | Water (condensation) | Normal |
| Slippery, brownish, near a wheel | Possibly brake fluid | Stop: do not drive |
| Rainbow sheen, smell of gasoline or diesel | Fuel | Stop: do not drive |
Not sure? See our guide to a car leaking water for the other fluids.
When an oil leak becomes urgent
- The oil pressure light comes on. Pull over as soon as it is safe and switch off the engine. See oil pressure light.
- A big puddle, or the level drops fast. Do not drive until the car has been looked at. Call a mobile mechanic or recovery.
- Smoke or a burning smell from under the hood. Oil may be dripping onto the hot exhaust. Stop and let a garage check it before driving further.
- Blue smoke from the exhaust. This points to oil burning inside the engine rather than an outside leak. Get it checked soon.
Likely causes, most common first
Loose drain plug or worn washer
The drain plug at the bottom of the oil pan can work loose, its sealing washer can fail or its threads can wear. Drips usually start from the lowest point of the engine. Often noticed soon after an oil change, and usually a cheap fix.
Oil filter loose or badly fitted
Read the fix guideA filter that is not tight, has a damaged seal or a cracked cap leaks oil around its edge. Again, often shows up shortly after a service.
Valve cover gasket
The rubber gasket on top of the engine hardens and cracks with age. Oil seeps down the side of the engine and can drip onto the exhaust, causing a burning smell. One of the most common leaks, and usually easy for a garage to reach.
Oil pan (sump) gasket
The seal between the oil pan and the engine wears, or the bolts work loose. A damaged or cracked oil pan, for example from hitting debris, also leaks here.
Rear main seal
The seal where the crankshaft meets the transmission. Oil appears between the engine and gearbox. The seal itself is cheap, but replacing it usually means removing the transmission, so the labor bill is high.
What it costs to fix
Typical garage prices for the common leaks, parts and labor together. US figures are RepairPal estimates quoted by Synchrony, plus ThePricer for the rear main seal; UK figures are from Bumper.
| Repair | US | UK |
|---|---|---|
| Valve cover gasket | $240–$285≈ £190–£220≈ €220–€260≈ A$360–A$430 | ≈ $96–$640£75–£500≈ €87–€580≈ A$140–A$960 |
| Oil pan (sump) gasket | $420–$500≈ £330–£390≈ €380–€450≈ A$630–A$750 | ≈ $150–$320£120–£250≈ €140–€290≈ A$230–A$480 |
| Rear main seal | $650–$1,500≈ £510–£1,200≈ €590–€1,400≈ A$980–A$2,300 | ≈ $580–$2,600£450–£2,000≈ €520–€2,300≈ A$870–A$3,800 |
A loose drain plug or filter is usually far cheaper: often just a new washer or filter and a top-up. If the garage needs to find the leak first, expect a diagnosis charge. Trucks, SUVs and luxury cars cost more for the rear main seal. Ask for a written estimate, and for the leak to be confirmed, before agreeing to a big job.
DIY or garage?
How to prevent it
- Check the oil level about once a month, and look at the ground where you park.
- After an oil change, check for drips over the next few days.
- Change the oil at the interval in your owner's manual.
- Fix small leaks early, before oil damages hoses and other parts or the level gets low.
Questions drivers ask
Can I drive with an oil leak?
With a small leak, usually yes for a short trip to a garage, as long as the oil level is correct. With a larger leak, a dropping level or a long journey ahead, leave the car until it has been inspected. If the oil pressure light comes on, stop as soon as it is safe and switch off the engine.
How do I know it is oil and not another fluid?
Dab the drip with white paper. Engine oil is amber, brown or black, feels greasy, does not evaporate and stains the ground. Coolant is usually colored and smells sweet. Red or reddish fluid is more likely transmission or power steering fluid. A slippery fluid near a wheel may be brake fluid: do not drive.
Why does my car smell of burning oil?
Leaking oil can drip onto the hot exhaust and burn off, which gives a burning smell and sometimes light smoke from under the hood. Get it checked soon. If there is heavy smoke or you see flames, stop, switch off and get everyone out of the car.
Do oil stop-leak additives work?
They are much cheaper than a repair but are not a substitute for fixing a confirmed leak. Have the source found first.
Is a rear main seal leak serious?
It is usually a slow leak, but it is the most expensive common oil leak to fix because the transmission normally has to come out to reach the seal. Make sure the garage has confirmed the source, because oil from higher up the engine can run down and look like a rear main seal leak.
Sources
- RAC: Car leaking? How to identify liquid dripping from your car (accessed November 6, 2026)
- Bumper: Car oil leak repair cost (UK) (accessed November 6, 2026)
- Synchrony: How much does it cost to repair car oil leaks? (RepairPal and CarParts.com figures) (accessed November 6, 2026)
- ThePricer: Rear main seal replacement cost (accessed November 6, 2026)
General information only. Every car is different: check your owner's manual, and if anything involves brakes, steering, tires or a burning smell, have a qualified mechanic look at it before you drive on.