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Engine Oil Amount
Posted: 25 Jul 2018, 23:33
by LM10
Hey folks. Since I've read different stuff on how bad it would be to put more than max amount of oil in an engine and since I know there are a bunch of clever people with technical knowledge here, I wanted to ask.
For example, if the oil level is at the max mark on the dipstick when 4 l of oil is in it, what can the causes of, let's say, 200 ml more oil than that be? Are there any tolerances above the max amount the manufacturers still put? The extent of how much more oil would you consider as too much and definitely harmful and would you be more afraid of destroying the engine or the catalyser?
Re: Engine Oil Amount
Posted: 26 Jul 2018, 00:10
by Big Tea
LM10 wrote: ↑25 Jul 2018, 23:33
Hey folks. Since I've read different stuff on how bad it would be to put more than max amount of oil in an engine and since I know there are a bunch of clever people with technical knowledge here, I wanted to ask.
For example, if the oil level is at the max mark on the dipstick when 4 l of oil is in it, what can the causes of, let's say, 200 ml more oil than that be? Are there any tolerances above the max amount the manufacturers still put? The extent of how much more oil would you consider as too much and definitely harmful and would you be more afraid of destroying the engine or the catalyser?
It depended very much on the individual engine. Most would be completely unaffected by 200ml
Re: Engine Oil Amount
Posted: 26 Jul 2018, 05:04
by Maritimer
Too much can cause foaming in some engines as well as excess consumption. Usually you have around half a litre of wiggle room though, depending on how much the sump holds.
Re: Engine Oil Amount
Posted: 26 Jul 2018, 08:21
by strad
too much will build up pressure in the sump.
Re: Engine Oil Amount
Posted: 26 Jul 2018, 10:37
by LM10
Thank you for your answer. So I don't need to panic much (i.e. not starting the engine) and can pump it out in my free time.
Re: Engine Oil Amount
Posted: 26 Jul 2018, 10:45
by MtthsMlw
My father's lawnmower has the max. dipstick amout times 4 in it and it runs just fine. I keep telling him that this can't be good for the engine over the long term but he doesn't care
Re: Engine Oil Amount
Posted: 26 Jul 2018, 10:45
by Big Tea
LM10 wrote: ↑26 Jul 2018, 10:37
Thank you for your answer. So I don't need to panic much (i.e. not starting the engine) and can pump it out in my free time.
Just changing the oil filter should cover it. If freshly changed, take it off and stand it in a tray to drain. as long as the rubber is ok reuse.
Assuming a cartridge filter!
Re: Engine Oil Amount
Posted: 26 Jul 2018, 12:14
by Tommy Cookers
as others have said oil foaming (due to churning) is more likely with 'excess' static oil level
oil foaming may trap air in the hydraulic lifters and they will partially collapse (and sound like a machinegun battle)
this is bad for the camshaft etc
you might have this problem eg at trackdays or with dragstrip style driving even with 'correct' oil level
depending on the engine orientation and the type/make of oil and its foaming resistance
Re: Engine Oil Amount
Posted: 26 Jul 2018, 17:50
by LM10
@MtthsMlw: Wow, that sounds crazy.
Hopefully he still will be able to mow the lawn for a long time.
@Others: Thank you, now I have a better understanding about the effects and what to do.
Re: Engine Oil Amount
Posted: 26 Jul 2018, 20:02
by strad
What Big Tea said.
Used to be the filter held a quart but many these days only hold a half quart.
Just check the oil afterward and fill to the correct level.
Re: Engine Oil Amount
Posted: 28 Jul 2018, 07:23
by J.A.W.
My M-B owners hand-book states that overfilling with oil.. may/will damage the catalytic converters..
But pre-catalytic converter emissions tech.. back in the day..
Some hi-po car makers still using wet sumps..for homologation of 'production' racing machines..
would utilize windage-trays/crank-scrapers.. to stop oil churning-power loss/aeration-foaming etc,
while still advising running a static 'overfill' oil-level..to duly ensure the oil-pump pick-up would accommodate any 'G-force' oil surge.. to the walls of the sump.. such as in long, fast corners..