The title says it… is there a margin of safety built into oil systems such that overfilling a little isn’t necessarily bad? If so how much is it OK to overfill by? Does it vary from car to car? Thanks!
When the oil capacity is like 4.7 qts, you put 5.0 qts in.
Tester
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Have a trucker bud, not saying it is right, but after he takes his truck, the wifes car and the 2 kids cars for an oil change he gets it home and adds an extra quart of oil. I am sure it must vary from model to model. I don’t want to tell him that is not good idea, as he is a little anal retentive, and who am I to contest him.
It depends.
Some cars with bigger oil pans…8 quarts… can easily take an extra quart. Most can take 1/2 quart with no issues. 1/4 to 3/8 inch over the full mark is usually OK.
There is no definite answer to your question. Especially since you did not identify the vehicle.
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I would imagine it does. Why are you asking ? And why are you not just using the dipstick to put the oil at the full level on this mystery vehicle ?
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@riverofwind
The concern is when the level of oil in the oil pan is high enough for it to reach the crankshaft. That means the crankshaft will whip the oil into a foam. Oil pumps cannot sustain oil pressure with foam, so the oil pressure drops, leading to wear and damage.
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@VOLVO-V70 I can think of scenarios in which it would matter. What if I accidentally overfill? What if I want to just add a quart for simplicity’s sake knowing ahead of time I’ll go a little bit over? My mystery car is a BMW… Also I am curious in the first place intellectually.
I’m assuming your BMW might have an engine oil level sensor?
If so, I wouldn’t overfill, not even by a little bit
If you overfill enough to trigger a warning message/light, it’ll be quite annoying, as you’ll have to drain engine oil
Good Grief , why do people make things so complcated ? Your BMW may have a dash readout and the oil container has a cap so just add what is needed and keep the rest for when it needs more.
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I think 10% over would be a good rule-of-thumb limit.
There are LOTS of BMW engines. You might as well have told us it is blue… would be as relevant… which is not at all. The older 3.0 six can take an extra 3 quarts with no issues. The newer 4s cannot.
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Right the “full” mark on the dipstick is the sweet spot, but diy’er me, I don’t drain any out as long as it is 1/4 qt over or less. How sensitive an engine is to overfilling varies vehicle to vehicle.
On a practical basis, while a bit of a messy job, but isn’t overly difficult to drain a little out.
@VOLVO-V70 Do you tend to be negative most of the time?
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@Mustangman Sorry I’m not terribly car savvy… 2002 BMW 330 Ci.
An 02 BMW 330i takes 6.9 quarts with a new filter. An extra half quart is no problem. Even as much as a full quart would be ok… but don’t. Pour 7 in and stop.
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I have had at least 2 engines over the years that would use more oil if I kept the level near Full, so I kept it nearer to Add.
Why would you want to overfill?
Sorry I didn’t make this clear I’m not completely emptying and refilling the oil system just topping it off as I’m at the minimum on the dip stick now. Thus the whole accidentally overfilling thing. Sounds like some of you knew this already while others didn’t… anyways I’ll probably be erring on the side of caution and adding a little less than I need to get to max to be safe.
I check my oil level every 2 weeks before I start the vehicle. Sometimes I have only needed 1/8 of the quart bottle to return to the full line .
@VOLVO-V70 Thx me too ~2 weeks. I’m only filling up once it gets close to minimum tho.
The minimum line is usually 1 quart low . I don’t want my vehicles to get that low of oil . Just how hard is it to add 1/2 quart or even less since you all ready have the hood open .