Why/ why not run oil level at MIN?

[sorinal]

It should heat up faster because there is a smaller mass of oil to be brought up to a certain temperature; by some fast calculations it takes 100+ watts of energy to bring 1L/qt. of oil from ambient to operating temperature.
Will it overheat? The oil cooling capacity should be the same because, the same amount of oil will flow and get in contact with the engine, there is just a smaller puddle in the oil pan. Thermal inertia is definitely lower.
OCI will have to be shorter, but it would also be cheaper.
This seems like a really good idea for a short-triper. Am I missing something?

In my case; my old Honda had a min-max of 2.5-3.5 and i've always just bought and poured in 3 bottles of whatever was on sale @ 6 month OCI (2-6k miles). The engine is tip-top, but the car is totaled . Now, my new Toyota has a min-max of 2.7-4.2 sooo I could do 3 bottles (which feels low) or I could do 4 bottles at ?... 6 month...1year... 6k miles... 10k miles... I don't know.

 

[Matt1357]

I'm just guessing here, better cooling and less deposits

 

[loneryder]

in some vehicles with weak or inadequate PVCs, it’s a good idea to keep your oil fill between the full and low mark. Not the low mark. I fill my Harley 103 engine about a half qt low and get less oil in the throttle intake.

 

[vavavroom]

The difference between max and min is usually a quart. That's a fifth to an eight of the total capacity. How much faster will the oil warm up because of reduced quantity and how is that potential benefit offset by the advantages of having a larger quantity of oil than bare minimum? I'd go with more oil.

 

[ripcord]

Contaminates. Dilution is the solution....

Also, why live on the edge? You'll have to check the level more frequently because there is a smaller margine of error, and what about that hard left corner? Are you sure you'll never starve the oil pickup when the oil is low and it's all sloshed to one side?

 

[oldcodger]

I tend to believe that every degree of heat removed by the oil the better. Also you would have no cushion if a malfunction (leak) should occur.

 

[Vercingetorix]

Lighter weight running less oil.

 

[edyvw]

1. Better cooling.
2. More oil means more cleaning, more volume to absorb deposits.
3. Less possibility to lose pressure in aggressive cornering.

 

[Invisible]

Your post about running your oil on the MIN level for quicker heating caught my eye, and I gotta say, it's a unique take! It's kinda like thinking wearing less clothes in winter will get you ready faster - sure, you might save a couple of minutes, but aren't you forgetting about the cold?

So, you're saying less oil heats up quicker, which sounds logical on paper. But remember, oil isn't just there to get warm. It's like the life juice for your engine, doing all sorts of important stuff like keeping things running smoothly and keeping the engine cool. Going with the bare minimum is a bit risky, kind of like going on a road trip with just enough gas to maybe get there.

And about the cooling, I get where you're coming from, but it's like saying if you have less water in your pool, you can still swim the same. Technically true, but with less oil, it's got a lot more work to do, and it's gonna get hotter than it should.

You mentioned doing shorter oil changes to save money. It's tempting, like grabbing sushi from the discount bin. Saves cash now, but might leave you with a big repair bill later, kind of like a bad stomach after that sushi.

With your old Honda, tossing in 3 bottles and calling it good was a bit like cooking with whatever's left in the fridge. Sometimes it works out, sometimes it's a bit of a mystery meal.

Now, for your new Toyota, deciding between 3 or 4 bottles sounds like trying to guess the weather. Sure, you can take a guess, but wouldn't you rather be safe than sorry? Your engine doesn't care about the cost, it just doesn't want to be left thirsty.

So, to wrap it up, think of your engine like a good buddy. You wouldn't skimp on care for a friend, right? Same goes for your engine. Better to give it a bit more oil than it needs, just to keep it happy. After all, dealing with a car problem because you tried to save a few bucks on oil is like stepping over dollars to pick up dimes. Keep it simple and your car will thank you for it.

 

[redbone3]

On a TV show I saw engines being run with low oil levels. Surprisingly, they made more power. The theory was that there was less oil mist/droplets in the way of the whirling engine components and the oil was less aerated. I have found that my VW Passat with direct injection and a turbo blows out the first .5 qt of oil after an oil change in quick order, then uses very little oil. I suspect the windage tray is less than 100% effective at preventing oil aeration and when the level is .5 qt low that helps out the situation. So, when I do an oil change I leave it .5 qt low and when adding oil I fill only until it is .5 qt low. With the oil too low, you run the risk of the oil pickup not being actually in the oil on a sharp turn, which would definitely not be good.

 

[doublebase]

I just don’t think the extra (whatever amount of time) an engine with less oil takes to heat up compared to an engine with proper oil level does, is worth much of anything. Much less the risk of carrying less oil that would have to in theory work harder than an engine with more oil, in terms of holding contaminants (and I know you mentioned shortening up the interval). Also, some of these direct injected engines have fuel contamination issues, to take away oil from a sump would really hurt the fuel/oil ratio.

Engines heat up pretty quickly as it is right now, they’re all aluminum (blocks/heads), and some exhaust components are double walled with a space between, which increases temperature and gets an engine into closed loop quicker…and actually some exhaust manifolds are integrated right into the head. I’ve heard nothing about issues with engines not heating up quick enough. As for the lower resistance with less oil - these engines already are running with low viscosity oils (0W20/0W16/0W8) with low tension rings, how much less resistance could one possibly need or want? I wouldn’t purposely reduce oil level capacity, to me oil level is my number one priority when it comes to maintenance. Just my opinion. But I like your view of thinking outside of the box.

 

[zray1]

Why stop at the minimum ? Just put enough oil in to cover the oil pick up tube in the oil pan



PS: : real answer : the more oil you have the cooler it will be. Fill to maximum level, a 1/4” more wouldn’t hurt anything.

Z

 

[Panos]

it takes 100+ watts of energy to bring 1L/qt. of oil from ambient to operating temperature.

You should use Watthours (Wh) while proposing an amount of energy for a task.
Watts alone mean Power.

 

[John105]

Why not be like those neutral drop guys and run on twigs and paint and finish off with Fabuloso? Even I was surprised a jeep in-line six kept going. My wife’s GM instantly threw a rod.

 

[barryh]

It should heat up faster because there is a smaller mass of oil to be brought up to a certain temperature; by some fast calculations it takes 100+ watts of energy to bring 1L/qt. of oil from ambient to operating temperature.
Will it overheat? The oil cooling capacity should be the same because, the same amount of oil will flow and get in contact with the engine, there is just a smaller puddle in the oil pan. Thermal inertia is definitely lower.
OCI will have to be shorter, but it would also be cheaper.
This seems like a really good idea for a short-triper. Am I missing something?

In my case; my old Honda had a min-max of 2.5-3.5 and i've always just bought and poured in 3 bottles of whatever was on sale @ 6 month OCI (2-6k miles). The engine is tip-top, but the car is totaled . Now, my new Toyota has a min-max of 2.7-4.2 sooo I could do 3 bottles (which feels low) or I could do 4 bottles at ?... 6 month...1year... 6k miles... 10k miles... I don't know.

I think your logic is sound in the right circumstances.

I do 3000 miles between oil changes and the engine appears to burn negligible oil between changes. In those circumstances filling much above min is a waste of good oil and is environmentally unsound. I have two caveats: to be sure the engine isn't burning oil by an occasional check on the dipstick but after 9 years of observation I'm comfortable with that. The other is to be sure there is nothing at risk of inadequate splash lubrication such as a timing chain.

On my motorcycle if I were to fill to the full mark it would just pump some of it out the breather. BMW issued a service bulletin which amounted to saying - don't fill above half way between min and max, so I don't and it consumes very little oil.

 

[mitsuman47]

If you’re short tripping the car and worried the oil isn’t making it up to temp fast enough, you’d be better off running oil pan and engine block heaters year round. I doubt you’d see much of a benefit in the hotter months. But, it would be better than running the oil low.

 

[SHOZ]

I have a problem with my mower where it never runs long enough to heat up the oil. I think I'll run it lower on oil next time I change oil.

 

[RDY4WAR]

I tend to favor the lower end. In my wife's Mustang, I fill it to halfway up the crosshatch and it's maybe a 1/4 qt low at 15k miles.

 

[joekingcorvette]

I wish my Civic had a 6 quart oil pan. IMO the oil would take longer to get contaminated versus a 3.8 quart full level.

 

[c502cid]

For us old timer gas jockeys, we checked a lot of oil at those full service pumps, you never added oil until a car was a quart low, if only because it was adding a quart of oil or nothing.

Now in general, modern cars don't use nearly as much oil. Oil and transmission fluid are, again in general, the only two systems that have a low and full line. It's perfectly safe anywhere on or in between the two. I think this is a great discussion and falls between the two faithful BITOG responses.

The engineers know what they are doing.
It's cheap insurance.