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Not strictly true.
Oil should be checked when cold.
It's actually better for an engine to be run slightly underfilled than overfilled.
If you top up to "max" on a cold engine, then that's pretty perfect.
Although providing you use the same method every time you check, your results should be fairly consistent.
If warm filling, aim it to be just under the maximum mark.
If you're a "cold checker" and check it one day when it's hot, it'll look low, and the temptation is to add some. It could be too much,
the correct level for your dipstick oil is anywhere between the minimun and maximum levels. Not outwith that.
To the OP, yes, I think you should take it back. Agreed, 3/8" shouldn't do any major damage, it's probably about a half litre or so but you paid for a job to be done properly, and it hasn't been.
Quote:
Originally Posted by Tightwad
Your engine is NOT overfilled! I repeat......Your engine is NOT overfilled!!
Why?
It is not proper to take oil level on a cold engine.
At least one quart is normally held up inside the engine in galley ways and clinging to parts inside the engine when hot.
Warm your engine to normal operating temp with a short drive (NO idling please!) THEN shut engine off to check your oil level. THAT is the proper way to check oil.........
***-EDITED*** Just noticed loads of us posted the same thing at the same time **
Last edited by bobman; 12-12-2011 at 04:49 PM..
Reason: more detail
You want to check your oil COLD or after the engine has set for a while so that the oil up top has a chance to drain back to the pan. Just a few minutes will do. The oil that stays up top is less than a pint not a quart.
You don't want to overfill and wind up having your crankshaft spinning in the oil. This causes the oil to foam up and thin out providing no protection. This is why overfilling can damage an engine.
I agree that 3/8 is not too much over full.
Not strictly true.
Oil should be checked when cold.
It's actually better for an engine to be run slightly underfilled than overfilled.
If you top up to "max" on a cold engine, then that's pretty perfect.
Although providing you use the same method every time you check, your results should be fairly consistent.
If warm filling, aim it to be just under the maximum mark.
If you're a "cold checker" and check it one day when it's hot, it'll look low, and the temptation is to add some. It could be too much,
the correct level for your dipstick oil is anywhere between the minimun and maximum levels. Not outwith that.
To the OP, yes, I think you should take it back. Agreed, 3/8" shouldn't do any major damage, it's probably about a half litre or so but you paid for a job to be done properly, and it hasn't been.
spent 40 years as an engineer for a major engine manufacture so COLD is never the right way. Let it sit for a bit after you shut it off then check is ok but never bone cold. never........
No point alluding that being an engineer makes you somehow superior to all the other engineers out there without sharing the benefit of your wisdom and experience with us.
Quote:
Originally Posted by Tightwad
spent 40 years as an engineer for a major engine manufacture so COLD is never the right way. Let it sit for a bit after you shut it off then check is ok but never bone cold. never........
You know, for whatever reason, when I check oil cold or hot after sitting a few minutes so any oil on top of the head or in the cam valley drains back - I get the same level. And this on a wide variety of cars. A/T fluid seems to be much more sensitive to temperature raising the level.
Go figure. I'm an engineer too, although working on nuclear rather than internal combusion topics.
Not mentioned but more important as a practical matter is to check the oil with the car/tractor/mower/whatever level. Bikes you need to check the owner's or shop manual as to if you should check oil on the side stand (bike on a level place, both fore and aft, left and right) or with the bike itself level as it would be on a centerstand if it has one. Most fairly recent 4-stroke Japanese bikes have a window in the crankcase allowing direct observation of oil level with the bike level.
I've always checked them cold. I got in the habit when I was working for Northern Natural Gas Company. We had to check the oil every single day before we started a vehicle.
Checking the level only requires the engine be off for a couple of minutes. Hot or cold doesn't matter. What does matter is the allowables by Nissan as to the clearance between the fluid level and the crankshaft. Nissan is noted for running the crank right at the fluid level. If it is indeed 3/8" above the full mark, the crank will be whipping the oil into foam and you will do damage to the engine as foam doesn't lubricate. On an old FE or CSB, no big deal, on a Nissan- big deal. Take it back and have them do it right.....that is what you paid them to do, right?
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Uhmmm ...
I do my own oil changes, and here is what I *see*.
I drain the oil, clean the plug, throw the old filter away, and *other things*.
So I figure, ALL the oil out of the engine should be almost all gone, no ???
Then I put the plug back, and install a new filter.
I put the exact amount of oil in that the manual suggests.
Then I check the oil right afterwards, and the oil level is slightly above the high/full mark (no oil in filter yet ...)
Then I run the engine, I do not rev it up at all, let it run for a minute or two and stop the engine.
I wait about a minute, and check and the oil level is always exactly at the high/full mark.
I never Top Off anytime.
When I am ready to change oil again, the oil level is about 1/8 of an inch below the high/full mark. This is after about a few minutes of running the engine - trying to get it correctly on the ramps)
I guess I still have a good engine (128,000 miles on engine).
I wonder ...
Why do so many drivers check their oil all the time so often ??
They do not trust the low engine oil light ?
Or is it too late when that light comes on ??
Just wondering ...
Since I never check oil *in between*, I have no idea what the oil level is right after I stop driving, or what it is after a whole day in the garage.
Have to do that some day, just to see ...
Some more wondering.
Do automotive engineers have a secret wish to punish people who do their own oil changes ?
Why is the oil drain plug and the oil filter almost always in places you barely can see ???
Why is the oil filter above some plate, that drains the oil that drains out of the engine, after you remove the filter, to a place that is right above your chest ???
For some reason, I think they are just snickering while they design the engine.
I’m not an engineer…
But I’ve read many manuals and not one has ever recommended to check oil when it warn or hot, It’s always cold and befor you start it.
Why not cold ? Need to allow for expansion when heated to operating temp.
No point alluding that being an engineer makes you somehow superior to all the other engineers out there without sharing the benefit of your wisdom and experience with us.
There is an SAE standard for the process of marking a oil dipstick (gage) that is somewhat complex. Sadly, I can't find the exact spec. but I did find a spec for automatic transmissions that is essentially the same as motor oil spec.
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