Question About Checking Oil

[jestevens]

Hi,

My friend has a 2014 Mirage DE and he is concerned about the oil level. He's shown me pictures of the dipstick when the engine is completely cold (first thing in the morning) vs about 10-15 minutes after warming up the engine and shutting off. When cold the oil level seems alarming - down below the bottom hole. After warmed up the level seems what I would consider to be normal - just a little bit below the top hole. I'm surprised by the difference in measurements. Can anyone say whether it's best to measure warm/hot or cold?

He tried to taking it to the local Mitsu dealer just to ask the same question but they were too busy to help. He's bought a quart of 0W-20 and was just going to top it off using the cold measurement.

I tried reading the manuals for the DE and one year says "before starting the engine.." and the next year says "after shutting the engine off.." so it's not very clear.

There was another thread with this title but that one seemed more about overfilling.

Thanks for your advice!

[foama]

Warm oil does expand slightly, but not enough for most folks to notice.
The big difference you describe is not linked to normal thermal expansion. I would check for other causes.

1) Before checking oil level, make sure the car is parked level on a flat surface! If not, the dipstick indication will be way off.
If the passenger side of the car is lower, for example parked with wheels in the gutter on the side of a street, the dipstick will indicate much higher oil level than it actually is.

2) Wait at lest 30 seconds after turning the engine off before measuring. Even better, check after getting back to the level parked car.

3) The difference between the bottom and top hole of the dipstick relates to about 0.5L or in medieval units about half a quart.

4) These cars usually consume very little oil, in fact, most require no refilling between oil changes. None the less, if all fluids are not kept at correct levels, expensive repairs can be expected.

[jestevens]

Thanks for your response

[Loren]

The Mirage only has a 3 quart capacity, that's not a lot. Most cars, the capacity between the two marks on the dipstick is a quart. On the Mirage, it's more like a half quart.

Anywhere between the two marks is okay, hot or cold.

I've never noticed the "expansion" of oil on the dipstick, that's new to me. What I more typically notice is that if the engine is REALLY cold, all of the oil is down in the oil pan and the level reads a little bit higher. If you check it warm, a lot of oil is up inside the engine, in the oil filter and oil galleys, and the level reads lower. We probably get a little less of that with the Mirage because it uses super-thin oil that likely drains back into the pan a lot quicker.

If you want what's "best", check the oil level with the engine warm, and have it right at the full mark plus or minus half the distance to the low mark.

[jestevens]

That’s why I posted. You’d think that if the engine was cold -more- oil would be in the pan/sump but the pics I saw showed the exact opposite. When it was warm it looked perfectly fine between the marks just a little short of top hole. But cold it was just on the tip of the stick, below the bottom hole. So that would be at least a quart to get it right cold then.

I think he better just add some to be safe.

As far as I know he’s checking it in a level parking garage slab.

Thanks all!

[Loren]

If he's a noob, there are a lot of variables, as I'm sure you know. Sometimes checking once, the oil won't "stick" to the dipstick the right way, always good to check it twice to be sure. I think a major thing is that 0W20 oil, especially when it's fresh and clean, is VERY hard to see on the dipstick, anyway. And the Mirage dipstick is particularly hard to read. They didn't put any extra machining into it, nothing to really "grab" the oil and make it visible.

Also, sort of wonder if he's just pulling the dipstick out and reading it... vs pulling it out, wiping it off, and putting it back in to get a cleaner reading.

I still think it's best to check the oil with the engine warm, and after it's rested for 5-10 minutes to settle most of the oil back into the pan.

[Mark]

ThatÂ’s why I posted. YouÂ’d think that if the engine was cold -more- oil would be in the pan/sump but the pics I saw showed the exact opposite. When it was warm it looked perfectly fine between the marks just a little short of top hole. But cold it was just on the tip of the stick, below the bottom hole. So that would be at least a quart to get it right cold then.

I think he better just add some to be safe.

As far as I know heÂ’s checking it in a level parking garage slab.

Thanks all!

I don't see anything in the owner's manual indicating the engine oil of a Mirage needs to be warmed up before checking the engine oil level.

If my level engine sat all night & the oil is just barely on bottom of the dipstick, I would add oil to the top fill mark. I wouldn't overfill past that mark, but I would not feel comfortable using an engine that started out that low with oil in the morning. Unless the manufacturer states the engine must be warm, I would add oil to a cold engine.

Even if a small amount of oil drains out of the filter overnight, that small amount isn't going to matter if you refill to the top mark on the dipstick. Consider the opposite - the oil filter had drained some overnight & the engine is still low on oil before you start out in the morning.

Has someone experienced otherwise?

Example: Your Mirage is low with oil first thing in the morning (barely reads on the bottom of the dipstick). You warm up the car, check it again, & now the oil level looks perfectly fine. Has someone seen this?

[Loren]

I don't check the oil in my Mirage that often. It doesn't burn any or leak any. I check it maybe every 3 months. Maybe. Back when I was autocrossing it, I checked it a little more often, and may have even added a dribble of oil every few months.

Weirdest thing I've experienced with oil level in general, other than letting the oil level get low enough for the oil light to come on, which happened every other day on my first car... it smoked... a lot. Aside from that, I once over-filled a Miata engine.

1.8 Miata engines take 4 quarts of oil. I owned one for 6 years. 4 quarts. Then, I ended up buying my first 1.6 Miata. 1.6 Miatas take 3.5 quarts, but I hadn't learned that yet. Changed the oil in my Miata... put 4 quarts in it like always. Went for a drive. Car started SMOKING like mad!

I couldn't make sense of it. All I did was change the oil. What the hell? Fundamental rule of troubleshooting: "Whatever you did last is probably what caused the problem." So, I checked the oil level. Found it way over full. Drained half a quart out. The smoking quit very soon thereafter.

That's when I learned that a) 1.6 Miata engines only hold 3.5 quarts of oil, and b) some engines don't take a whole lot of over-filling before they become extremely unhappy about it!

[Mark]

I don't check the oil in my Mirage that often. It doesn't burn any or leak any. I check it maybe every 3 months. Maybe. Back when I was autocrossing it, I checked it a little more often, and may have even added a dribble of oil every few months.

Weirdest thing I've experienced with oil level in general, other than letting the oil level get low enough for the oil light to come on, which happened every other day on my first car... it smoked... a lot. Aside from that, I once over-filled a Miata engine.

1.8 Miata engines take 4 quarts of oil. I owned one for 6 years. 4 quarts. Then, I ended up buying my first 1.6 Miata. 1.6 Miatas take 3.5 quarts, but I hadn't learned that yet. Changed the oil in my Miata... put 4 quarts in it like always. Went for a drive. Car started SMOKING like mad!

I couldn't make sense of it. All I did was change the oil. What the hell? Fundamental rule of troubleshooting: "Whatever you did last is probably what caused the problem." So, I checked the oil level. Found it way over full. Drained half a quart out. The smoking quit very soon thereafter.

That's when I learned that a) 1.6 Miata engines only hold 3.5 quarts of oil, and b) some engines don't take a whole lot of over-filling before they become extremely unhappy about it!

If an engine is known to burn oil or leak, checking your engine oil more frequently is warranted. If not, it's still a good practice to check at times.

I don't think anyone has suggested overfilling a Mirage. Unless a manufacturer states otherwise, I would check the oil of a level vehicle/engine first thing in the morning. If the oil level is at the "high" mark, it's not overfilled. If a cold engine is below the "low" mark, I would add some oil. That's the purpose of checking it.

I grew up driving lots of old tractors and other equipment. You started your day by checking the oil level in everything. Some of those tractors worked hard some days. The next morning you would check them again. The length of time is irrelevant here. It's comes down to usage, mileage, age of the engine, etc...

Unless the manufacturer states (some do) the engine must be warmed up to check the engine oil, I would check it first thing in the morning to get the most accurate reading of where things are at.

[Fummins]

I had a truck that leaked and burned oil so bad I had to check it every 3 hrs. I took it on a 11hr road trip and brought along a 5gallon pail of oil. Then had to get another one for the trip home lol.