Why Your Car Burns Oil and How to Fix It
Oil consumption is a common issue in older or high-mileage vehicles. Here’s what causes it and how you can address the problem:
Common Causes of Oil Burning
1. Worn Piston Rings
Symptoms: Blue/gray exhaust smoke, especially during acceleration
Why it happens: Rings no longer seal properly, allowing oil into combustion chamber
Fix: Requires engine overhaul or replacement in severe cases. Try a high-mileage oil or ring seal conditioner first.
2. Valve Seal Leaks
Symptoms: Smoke at startup that clears after running, oil in spark plug wells
Why it happens: Hardened or cracked seals let oil seep into cylinders
Fix: Valve seal replacement (can sometimes be done without head removal)
3. PCV System Failure
Symptoms: Oil in air intake, excessive crankcase pressure
Why it happens: Clogged or stuck PCV valve causes oil to be sucked into intake
Fix: Replace PCV valve ($10-$50 part, often easy DIY)
4. Turbocharger Issues (Turbo Cars)
Symptoms: Oil in intercooler piping, excessive smoke under boost
Why it happens: Worn turbo seals allow oil into intake or exhaust
Fix: Turbo rebuild or replacement
5. External Oil Leaks
Symptoms: Oil spots under car, low oil level without smoke
Common leak points: Valve cover gasket, oil pan gasket, rear main seal
Fix: Replace leaking gaskets/seals
DIY Solutions to Reduce Oil Consumption
Switch to Thicker Oil
Try moving up one viscosity grade (e.g., from 5W-30 to 10W-30)
High-mileage oils contain seal conditioners
Use Oil Additives
Products like Lucas Oil Stabilizer or Restore can help reduce consumption
Clean the PCV System
Replace PCV valve and clean hoses
Cost: $10-$50, 15-30 minute job
Check for External Leaks
Clean engine with degreaser, then monitor for fresh leaks
Tighten valve cover bolts to proper torque
Perform a Compression Test
Helps determine if piston rings are the issue
Rental tools available at auto parts stores