Troubleshooting Engine Oil Consumption

Diagnosis for Engines That Are Burning or Leaking Oil

checking oil
If you lose oil between changes, time to find out why. Getty

Is your oil level low between oil changes? If your car's engine is operating as it should, there will be no need to add oil. Unfortunately older engines rarely enjoy this luxury. As the engine wears, oil makes its escape. A little oil added now and then is nothing to worry about, but if you're adding a quart or more between oil changes, you may have a fixable problem in there. Your engine may be burning oil thanks to worn piston rings.

Your engine could also be leaking oil thanks to a bad gasket or cracked part. Or you could be losing oil through the head gasket into the cooling system. This can be an expensive repair.

Check the following symptoms related to oil consumption.

  • Smoke in Exhaust
  • No Smoke in Exhaust
  • Coolant Brown and Foamy
  • Oil Puddles or Drips Under Car

Symptom:

The car uses more oil than normal, but there is no trace of smoke from the exhaust. The oil level is low between scheduled oil changes. You never noticed it before and it doesn't appear that the oil is being burned by the engine. There is not a trace of smoke in the exhaust.

Possible causes:

  1. The PCV system is not working properly.
    The Fix: Replace PCV valve.
  2. The engine may have mechanical problems.
    The Fix: Check compression to determine engine condition.
  1. The engine's valve seals may be worn.
    The Fix: Replace valve seals. (Generally not a DIY job)
  2. The engine's gaskets and seals may be damaged.
    The Fix: Replace gaskets and seals as required.

Symptom:

Engine is using more oil than normal. Coolant appears brownish and foamy. Your car seems to be losing oil someplace, but there aren't any obvious leaks, and no smoke from the exhaust. You check your coolant and it looks like foamy root beer

Possible Causes:

  1. Blown head gasket.
    The Fix: Replace head gasket.
  2. Cracked cylinder head.
    The Fix: Remove and repair head, or replace cylinder head with new part.
  1. Leaking oil-to-water cooler. Some oil coolers circulate oil inside a chamber that is filled with coolant. This allows for the exchange of heat between the two systems. Sometimes a leak in the oil line inside this chamber can cause oil to leach into your cooling system.
    The Fix: Repair or replace oil cooler.

Symptom:

Engine is using more oil than normal. Oil puddles under the car when parked. The oil level is low between oil changes. You see puddles of oil under the car. Obviously you have an oil leaks. You may or may not see smoke or smell oil burning when you stop at a light, stop sign. or park the car. You should make sure the engine always has the proper oil level.

Possible causes:

  1. The PCV system is not working properly.
    The Fix: Replace PCV valve. Check and repair PCV system as required.
  1. The engine's gaskets and seals may be damaged.
    The Fix: Replace gaskets and seals as required. Finding them is the trick, and visual inspection is the best way.
  2. Oil filter may not be tightened properly.
    The Fix: Tighten or replace oil filter. Sometimes the fix is far more simple than you would have imagined!

Symptom:

Engine uses more oil than normal, and there is some smoke from the exhaust. The oil level is low between oil changes. It appears that the oil is being burned by the engine because of the smoke in the exhaust. You may or may not notice the engine doesn't have the same power as it used to.

Possible causes:

  1. The PCV system is not working properly. A clogged PCV system can cause major oil blowback, which means that oil is actually being sucked back into the engine through the air intake.
    The Fix: Replace PCV valve.
  1. The engine may have mechanical problems.
    The Fix: Check compression to determine engine condition. An engine with poor compression may be a simple fix, but it could also have major leaks in the rings, head gasket, or other places.
  2. The engine's piston rings may be worn. A worn piston ring causes engine oil to slip past. This means that engine oil will be found on the wrong side of the rings. This can be due to a worn ring, or in a worst case scenario, a grooved and worn cylinder wall.
    The Fix: Replace piston rings. (Generally not a DIY job)
  3. The engine's valve seals may be worn. Similar to worn piston rings, a worn valve seal will let oil slide through where it should not.
    The Fix: Replace valve seals. (Generally not a DIY job)