8 Causes of Excessive Oil Consumption (and How to Fix)

We all know the main purpose of oil is to lubricate the components of an engine, so they can keep running smoothly. There is a certain level of oil consumption in which an engine will have under normal conditions.

For modern engines, they should consume less than 1/2 quart of oil every 5,000 miles of driving. Most newer cars consume much less. This is not a lot of oil and most car engines will get along just fine with this much.

But there are still things that can happen to change this oil consumption by making the engine demand more oil. If you don’t supply the engine with enough oil or at least fix the problem that is causing it lose more oil, then you could end up damaging your engine.

Top 8 Reasons Your Engine is Using Too Much Oil

Below are the most common causes of excessive engine oil consumption.

1) Leaking Valve Cover Gasket

valve cover gasket leak

Valve cover gaskets provide a critical sealing function between the metal valve cover and the cylinder head. Like other gaskets in an engine, they prevent oil from leaking externally as well as internally into areas like the combustion chambers.

Over time, the valve cover gaskets can become hardened and flat. This causes gaps to form between the valve cover and head, allowing oil to leak through. External oil leaks from the valve cover area indicate likely gasket failure. But even without external leaks, worn out gaskets can permit oil entry past the valve guide seals.

How to Fix

Replace damaged and aged valve cover gaskets to restore proper sealing. Use quality gasket materials and torque specifications to prevent future leakage. Ensure the valve cover mates evenly with the cylinder head to avoid gaps that allow oil to leak through.

2) Bad Quality Oil

low oil symptoms

If you use the wrong type of oil in your engine, or your oil is simply old and has accumulated a lot of debris and dirt, then it will start to burn.

More importantly, old, dirty oil won’t be able to adequately lubricate the components of the engine because of its condition. This will force the engine to consume more oil.

If your engine oil is dark brown or black in color, get your engine oil changed as soon as possible. It’s an easy DIY job. All you need is new oil, oil filter, oil drain pan, car ramps, wrench, and about 20 minutes.

How to Fix

Change engine oil and filter as soon as possible if oil is dirty or degraded. Use the manufacturer recommended oil type and change intervals to prevent oil quality issues.

3) Worn Piston Rings

damaged piston

If you have worn out or damaged piston rings, oil will be able to seep through them and then enter the internal combustion chamber. This will cause the oil to burn while carbon deposits form on the piston rings and cylinders.

Worst of all, your oil level will continue to decrease making it necessary to constantly top off oil. Getting your piston rings replaced is the only good solution.

How to Fix

Getting your piston rings replaced is the only good solution for worn rings and oil consumption issues.

4) Valve Guide Seals

valve guide seals symptoms

Over time and high mileage, the valve guide seals can wear out or harden and shrink. This allows oil to be pulled past the seals into the engine’s cylinders during operation.

The oil is then burned in the combustion process, leading to excess oil consumption. Replacing old and brittle valve stem seals with new ones can often fix stubborn oil burning issues.

How to Fix

Replacing old and brittle valve stem seals with new ones can often fix stubborn oil burning issues.

5) PCV System Issues

bad PCV valve

The Positive Crankcase Ventilation (PCV) system is designed to pull vapors and excess pressure from inside the engine and redirect them to be burned in the cylinders. This prevents pressure buildup and allows excess oil mist and vapors to be recycled back into the engine.

Problems with the PCV components can disrupt this process and lead to oil burn. A clogged PCV valve or blocked intake path doesn’t allow proper vapor flow, causing pressure leaks past seals and rings into the combustion chambers.

Restricted flow causes oil mist to build up inside the crankcase, where it is then sucked into the cylinders. Oil consumption arises from both the increased pressure forces and recirculated oil vapors.

How to Fix

Inspect and replace any faulty PCV system parts like hoses, valves, and filters. This will help the system flow properly again and reduce oil getting past critical engine seals and rings.

6) High Oil Pressure

high oil pressure

When there is high oil pressure, oil will flood through the engine in excessive amounts. This oil will likely fall on the cylinders and get burnt up. This cause of high oil pressure could be due to a faulty setting on the vehicle’s central computer. A similar problem is adding too much oil during an oil change.

How to Fix

Diagnose and resolve the root cause of high oil pressure, whether from a faulty computer setting or too much oil added. Adjust pressure to normal levels.

7) Old Engine

old dirty car engine

The first five years of your engine’s life will be the best years. These are the years when the engine will need the least amount of oil because its components are still new and strong. But after you’ve put enough miles on your engine, the various seals and gaskets will start to deteriorate and cause small leaks.

This means the engine will simply consume oil quicker. In addition, older cars have bigger tolerances where components connect which can allow oil to get through spots which wouldn’t exist in modern vehicles.

How to Fix

Engine overhaul or replacement of major components may be needed in very high mileage engines but with the average cost to replace an entire engine being in the thousands of dollars, it’s often best to start thinking about replacing the car instead.

If it’s simply not in the budget to replace the engine or car, improving maintenance and using an oil formulated for high mileage engines can help mitigate increasing oil use. But you’ll still continue to lose oil and monitoring oil level becomes extremely important.

8) Synthetic Oil

synthetic motor oil

In most cases, synthetic oil lubricates engines better than conventional oils. But since synthetic oils are formulated differently, they have different flow properties. This means that synthetic oil is sometimes able to get through tighter openings than regular oil.

If you have an older engine or your seals and gaskets are starting to deteriorate, synthetic oil can often be the culprit when it comes to high oil consumption and you’re left with a low level of oil. Switching to a conventional oil will often stop any minor leaks.

How to Fix

Switch to a conventional oil which may stop minor leaks allowing synthetic oils to get through.

Read Also: 5 Causes of Car High Fuel Consumption

Frequently Asked Questions

 

What Are Common Signs That My Car is Burning Oil?

When your car is burning oil, you might notice a blue smoke coming from the exhaust or a burnt oil smell in the cabin. Your engine’s oil level may also decrease faster than usual.

Can I Still Drive My Vehicle If It’s Burning Oil?

You can drive your vehicle temporarily even if it’s burning oil. However, it’s important to address this issue promptly because prolonged oil burning can lead to engine damage due to inadequate lubrication.

If you absolutely need to drive while you wait for repairs, check your oil level at frequent (ie: daily) intervals and keep a quart of oil, funnel, and paper towels in the trunk of your car just in case.

If There’s No Smoke or Leak, Where Could My Car’s Oil Possibly Be Going?

If your car is losing oil but there’s no visible smoke or leak, the oil could be getting into the combustion chamber and burning off without producing noticeable smoke, or it might be escaping via worn internal engine components such as valve seals or piston rings.

 

Kevin

34 thoughts on “8 Causes of Excessive Oil Consumption (and How to Fix)”

  1. Ok so I have a 2012 Ford F-150 losing too much oil and smoking like heck when starting after sitting for more then 20 or so minutes. Could this be the cause of a bad cam shaft and or the crank and cam sensors and possibly some other sensor gone wrong or possibly all the above.? Thanks! Signed: (Sir): Jody L. Hall.

    Reply
    • Losing oil is usually caused by a bad seal, not a bad sensor. I would guess it could be a valve guide seal or something like that, but you would have to have a mechanic look at it to know for sure.

      Reply
  2. Hi
    My motor vehicle uses a large amount of oil and sometimes gives out a lot of white/blue smoke and then loses power, but does not do it all the time. What can cause this ?

    Reply
    • Many things can cause this, such as worn piston rings, valve seals, and even a blown head gasket. The solution is often an engine rebuild or replacement of the failing seal(s).

      Reply
  3. I have a 2017 Isuzu d teq x rider double cab with 65000 km on clock.

    It use to much oil to my understanding. No leaks, no smoke. After every 200km drive you can see oil level has drop.

    Reply
  4. I’m experiencing high level of oil shortage in my Nissan vannete( diesel engine)… with little smoke from the exhaust…
    I’ve added additive to the engine though.
    any help to revive the engine?
    pls.

    Reply
    • Depends on what damage was done due to oil starvation. If there’s no damage, just top off the oil. If there is damage, it’ll depend on how bad it is. A compression test can give you a better idea of that.

      Reply
  5. Refer cause no 4. This high oil pressure could be due to a faulty setting on the vehicle’s central computer.
    Is it possible to rectify this? please assist!

    Reply
  6. I am experiencing oil shortage and too much fuel consumption with My Toyotal Camry 2007, 2.4 Engine. I have checked for oil leakage but no sign of leakage. Please what do I do to resolve it. As my local mechanic has tried all he could but all to no avail

    Reply
    • Unfortunately, the 2007 4 cyl Camry had a known defect in its piston rings. Toyota had a program that extended the power train warranty, but that is expired now. The only solution is an engine rebuild best done with the use of s factory new short block if your car is worth putting $5,000 into at this point in its life.

      Reply
  7. Sadly all new engines now use very low strength piston rings to cut down on friction between the cylinder walls and rings all to improve gas mileage and make it “greener”
    They also use the thin as water 0W-20 oils for the same reason.
    As a result the weak oil retainer rings fail to keep the thin oil from being sucked or blown past these weak rings resulting in oil burning engines not seen since the 1950s.

    Ironically these “green” engineering measures have actually caused MORE pollution and early engine failures than has been seen for many decades.

    As a result, all new cars are now simply designed to FAIL instead of being designed to LAST.

    They are now throw away vehicles that cost 4 times as much as the ones that used to last twice as long and burned ZERO oil.

    Thin oil, weak piston rings, and GDI are the perfect storm the greenies wanted to finally destroy the internal combustion engine once and for all.

    Reply
    • Yeah, emissions and efficiency have definitely been a critical focus in most vehicles since the oil crisis in the 70s. There have been several advancements in engineering that allow modern vehicles to run 0W-20 oil, including tighter tolerances, smaller oil journals, and high quality synthetic formulas. Running a 0W-20 oil will do no harm to an engine that was designed to use it.

      I would argue that many premature engine failures are not due to the “green” engineering measures, but trying to rush an engine design out the door before it’s thoroughly tested and ready to go. For instance, early cylinder deactivation systems on some vehicles caused piston ring issues or excessive oil consumption like you described here.

      You’re right that vehicles cost a lot more now than they used to, but they’re not really four times more expensive. Inflation has driven the cost of vehicles up drastically in the last 50 years, so it’s apples to oranges comparing the MSRP of a new vehicle and an old one without adjusting for inflation. For instance, a 1971 Corvette coupe had an MSRP of $5,496.00. Adjusted for inflation in 2021 that would be $36,877.61 according to the Bureau of Labor Statistics (https://www.bls.gov/data/inflation_calculator.htm). A brand new C8 Corvette starts at $59,900, which is less than double the adjusted price. On top of that, the C8 is basically a supercar, offering vastly superior performance and safety compared to cars released 50 years ago.

      Reply
      • Application of general inflation rate to car price would be appropriate if costs to produce went up at that same rate. And since wages haven’t increased at the same rate, your argument is apples/oranges.
        Hence, United Auto Workers strike, coincidentally, this week.

      • What do production costs have to do with the reduced buying power of a dollar over time? You still have to adjust for inflation when comparing those numbers.

  8. Yeah, high engine temperature is also the cause. When the engine temperature increases, oil temperature too increases thus consumption increase. Though, this doesn’t consume too much oil compared to the other causes.
    NB: Just check on the engine coolant, and fix any problem that might be on your car cooling system (also, ensure that the fan movement is OK).

    Reply
  9. Hello, my diesel Hilux Surf car has constant engine oil shortage and is emitting alot of black smoke. What could be the cause please?

    Reply
  10. Questions
    My car Verna Hyundai 2011 transform model overhauled with replacement of piston, valves, etc but it is consuming oil when AC is put on.approx.1ltr oil in 400 km. The local mechanic tried all possibilities but could not rectify them. Please answer if possible?

    Reply
    • You probably have an oil leak somewhere. First check the drain plug, as this is a common cause of a leak. If the drain plug is leaking, use a crush washer when you change the oil. If the leak continues from this location, you may need to replace the drain plug or oil pan.

      You could also have leaks in other places. You’ll first need to identify the leaks before you can correct the problem.

      Reply
    • Definitely, since any leak can range from minor to severe. You’d likely see a puddle or steady drip of oil coming from the front of your engine if the level was dropping quickly. To avoid catastrophic engine damage from loss of oil, have your vehicle checked out by a mechanic.

      Reply
  11. Does over-heating cause oil shortage in engine? I am asking because i experienced a couple of overhearing last year, after fixing the problem i started noticing shortage of oil

    Reply
    • It’s possible. For instance if your car overheated because of a head gasket leak, the oil and coolant would mix. Some of both might burn off in the combustion chamber.

      Reply
      • But there is no oil sign in my coolant. Just a little smoke when starting for few seconds and the oil keeps going down

      • Perhaps you are just burning oil and the root cause of the overheating is unrelated. A leak down test should give you a pretty good idea of what’s going on either way.

    • My wife has a 2007 Toyota Rav4 with a 2.4 liter engine. It was very common for these to begin burning oil with age. I was told by a Toyota rep that it was caused from a piston and piston ring design flaw. They redesigned the pistons and rings to correct this. Apparently on the new pistons where the holes are locate on the oil control rings they added more drainage holes and made them larger to allow more oil to flow past which was said to prevent gumming and sticking of the rings. Once the rings gets stuck on the ring lands this would allow oil to get past and then get burned in the combustion chamber. Fortunately for us we had an oil consumption test done at the dealership. It failed the test which allowed us to get the top-end rebuild, this consisted of new piston rings gaskets fluids Etc. This work was done under warranty.

      Reply

Leave a Comment