DIY: Moderate
Car Using or Burning Oil: Causes and What to Check
Oil does not get used up the way gas does, so if the level keeps dropping it is going one of two places: burned inside the engine, or leaking out. Some engines use a small amount between changes. Your owner's manual may say what the manufacturer considers acceptable.
Stay safe first
- If the oil warning light comes on, or the dipstick shows no oil, shut the engine off and add oil before you drive any further.
- An engine run low on oil can be destroyed in a short time. Check the level often while you sort out the cause.
Blue smoke when you start the engine or after idling
Likely causes
- Worn valve stem seals or valve guides letting oil seep in while the car sits
- A stuck or clogged PCV valve
What to check
- Watch the tailpipe on a cold start and again after a long idle. A puff of blue-gray smoke that clears quickly points toward valve seals.
- Check and replace the PCV valve if it is due. It is an inexpensive part on most engines.
- Keep a log of how much oil you add and how many miles it takes, so a shop has numbers to work from.
Steady oil use with blue smoke while accelerating
Likely causes
- Worn piston rings or cylinder walls
- Crankcase ventilation (PCV) problems pushing oil into the intake
What to check
- Check the oil level at every fill-up and write down what you add.
- Have a shop do a compression or leak-down test if consumption is heavy.
- Ask a dealer whether any extended coverage or service update applies to your engine.
Oil level dropping but no smoke
Likely causes
- An external leak from the valve cover, oil filter housing, oil pan or rear main seal
- Oil dripping onto the exhaust and burning off, which smells acrid
What to check
- Look for fresh oil under the car and for wet, dirty areas around the valve covers, the oil filter and the oil pan.
- Check that the drain plug and filter are tight and that the filter has only one seal on it, especially if the level dropped right after an oil change.
- A burning-oil smell after a drive usually means oil is reaching a hot exhaust part.
Narrow it down for your vehicle
The same symptom can have different likely causes depending on your year, make, model and engine. Describe what you are seeing and CaliperAI will help narrow down the likely causes for your vehicle.
Related guides
General information about this symptom, not a diagnosis of your specific vehicle. Safety-critical work such as brakes, fuel and airbags is best left to a qualified mechanic.