In this day in age, during/post-pandemic, we’re witnessing used car prices are somehow rocketing sky-high. Some used cars have even outpaced new ones straight from the dealer, in terms of price. Man, what a bizarre time in history we are living in. I’d like to get into the details about how this makes any sense, but will leave that particular topic for an economist to explain for the time being. More importantly though, what happens when YOU buy a used car that is most likely overvalued, but has an internal oil consumption problem?
This is something you can’t predict when test driving, and more often than not, cannot sense or smell any oil burning off. It’s a problem that seems to sneak up on your vehicle at the worst possible time. The previous owner of the car might not inform you of this (if they even realize it), and now you’re stuck with a vehicle that reminds you of your old 2-stroke motorcycle, and not in a cozy, reminiscing-of-the-past way – Unless you strongly miss mixing and burning oil in your tank.
You might be asking yourself, “Did I cause this? How long has this been happening with this darn car? Is there any way to fix this myself- without paying an arm, leg, or who knows what?” If any of these questions stand true, keep reading on. There are certain checks you can apply to potentially fix your hungry vehicle or avoid being in this situation from the start.
What is an oil consumption problem?
When your car consumes oil rather than leaks it on the ground, you’ve got an oil consumption problem. The cause of this can be a variety of different factors, most commonly on engines that are old and have a number of miles racked up. It’s important to keep a close watch on your oil level regardless of if a consumption issue is suspected, as it takes less than a minute to check your oil with your dipstick when, say, you’re at the pump.
How do I know if my car is consuming oil?
This is commonly found by monitoring the level of oil in your car, by means of checking the dipstick (or getting a warning message on your dash transmitted by your oil level sensor, if you’re blessed with owning a fancier car). In some cases, you may see blue colored smoke being emitted from your tailpipe, or maybe it’s leaking out of a head gasket or valve cover and dripping onto a portion of exhaust pipe to be burned off this way (in this case, you will probably smell burning oil sooner or later – which has a similar scent to asphalt being laid when you pass the construction site, so use your “scent-ses” accordingly [don’t worry, that’s the only horrible pun I’m offering for the day]).
Keep in mind that a small bit of oil being consumed is normal, even in new engines. The generally accepted allowed amount ranges between: 0.0052 quarts to 0.3170 quarts per 621 miles, or 0.05 dl to 3 dl per 1000 km. Although this metric varies depending on the manufacturer, exceeding this would likely render a need for checking oil consumption.
Common causes for oil consumption
The most common reasons that your car is eating up oil are:
- You have an older car that has higher limits of oil consumption from the factory
- You’re using the wrong grade or poor quality oil
- Worn head gasket
- Worn piston rings
- Worn valve guides
- Worn seals or gaskets- Commonly valve cover, spark plug or other oil passage seals near exhaust manifold
How much does it cost to diagnose and fix myself vs a mechanic?
Of course, dedicating the time to correct this issue yourself will save you lots of money. However, deciding whether or not it is even worth your time to identify the source of the leak is the big question. If you’re short on time, a common practice is to have a qualified mechanic diagnose where the leak is coming from, then perform the actual replacement procedure yourself. This way, you save on the actual repair cost and can have “fun” doing the repair yourself with some added satisfaction of correcting a big problem.
Here are some fun dealer repair cost numbers related to oil consumption issues, to weigh-in:
(Pricing pulled from sample figures for a 2012 Toyota 4Runner V6)
- Cylinder compression test - $370 to $472
- Valve cover gasket replacement - $773 to $973
- Camshaft replacement (likely needs removal if accessing valves/guides) - $2,319 to $2,616
- Cylinder head gasket replacement - $4,852 to $5,863 (both sides)
- Piston rings/engine rebuild - $6000+
Yikes! But don’t panic yet…
What I can do to fix
There are a series of tests you can perform yourself to rule-out the possibility of having a problem with oil consumption. After witnessing your oil level drop many ounces month after month, or even week after week, what is the biggest and most infamous test that exists to determine this and where the problem lies? A compression test – and it might cost you nothing! Performing this relatively simple diagnostic procedure can help you rule-out or identify where the oil in your car is leaking to or where it is being burned off in the combustion chamber (leaking past valve seals, compression rings, oil galleys in engine block). If you have a basic mechanic’s tool set capable of removing ignition coils/plug wires and spark plugs, the only piece left to obtain is a compression testing kit. These are often available at auto parts stores for no charge if you borrow and return the item, although they are often times chewed-up by other customers who have been in your current situation. Decent compression testing kits are fairly inexpensive online or at parts stores; and I would be doing you, myself and the company I work for a disservice if I didn’t plug the Haynes manual for your model vehicle. The info inside can’t pinpoint the exact location of your leak, but can act as a guide to help you through the process of testing for compression (Chapter 2) and performing the steps needed to correct and repair the problem, once you’ve identified it.
Making your engine last as long as possible after a consumption issue
Sometimes, issues like this are more trouble than they’re worth, and people tend to live with the issue by topping-up oil as necessary as long as they are not spending over a certain amount of money on oil every month. If their engine performs well and doesn’t leak, and the only issue is that the engine devours a quart of 10W-30 every month- some find this as okay to deal with, rather than spending thousands of dollars on a problem that essentially only costs them an extra $10-$15/month. There are, however, simple things you can do to prevent huge issues from happening like this again after they’ve been fixed, or even from happening in the first place: • Use the recommended type (synthetic or non-synthetic) and viscosity (e.g., 10W-30) engine oil for your vehicle, as stated in the owner’s manual (extra points for using synthetic oil, although it is not absolutely necessary on some vehicles) • Regular oil changes - every 5k miles (varies by manufacturer) • Regular coolant replacement intervals, to prevent your engine from overheating • Stay up to date on replacing necessary parts (spark plugs, intake seals, PCV valve, air filter, etc.)