Should I have run out of engine oil?

Question

I have a Holden Captiva 5 LT (2013, petrol 4cyl) I had noticed the other day that my light for "Dangerously Low Oil Levels" had come on.

From my limited knowledge of cars, If my oil was filled last service, it should defiantly not have run out of engine oil in 9 months correct?

After checking the oil, it was pretty much out. I've bought a liter of oil, and put it in and it's barely gotten me to the first hash mark on the dip stick.

I have my car serviced like clockwork every 9 months, and it's due in 2 weeks for a service again.

(Note: No oil leaks or spots under the car in the driveway or at work, it's not burning the oil either.)

Answer 1

A liter or two of oil in nine months might be a lot, or it might be quite normal. It really depends on the condition of the engine and how and how much you drive the car. The engine is continually burning a tiny amount of oil, so over time this will result in some oil loss.

Also it sounds like you're not in the habit of checking your oil regularly, so it is possible that the last time the engine was serviced that the oil wasn't filled completely.

This could happen if the mechanic got distracted while adding oil and lost count of the amount put in, or if the oil level was checked before starting the engine and filling the oil filter.

Over time a very small leak can run through a non-trivial amount of oil – for example, if you're driving 25,000 KM/year and leaking one drop (roughly 0.05 ml) of oil per KM you would be loosing just over 900 ml in nine months.

Answer 2

That sounds like a lot of oil to go through in 9 months. Yes a small amount of oil gets burned as the engine runs but it's a very very small amount. Does the bottom of your car look oily at all either wet or built up with lots of road grime?

You may not notice it while parked but when the engine is running there may be a leak somewhere while the oil is pressurized. Also you may not notice you are burning oil especially if it is a few quarts over nearly a year. If you are burning a lot you will see the blue grey smoke but that is quite a bit. Your valve seals might be worn and that can leave some oil on the tops of the valves which will get burnt during startup too.

There is definately something going on and you might want to look into it before you forget to check the dipstick and have that light come on again. Having low pressure or even no pressure leads to engine failure pretty quickly.

From now until you find the problem check the dipstick after filling with gas but before starting the engine. This gives the oil in the head enough time to flow back into the oil pan to give you an accurate reading.