Underfill or Overfill?
- Thread starter boone88rr
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BlazerLT - I don't think that has a thing to do with crank slapping. If 16oz of extra oil in your engine while running causes the gauge to dance, then I really think there is something wrong with the sensor or the set up. Think about it - especially your oil pan level while the engine is running.
BlazerLT - you got me - hey man I believe you. It sounds interesting though - I mean if +1 pt of oil causes aeration, what happens on hills and corners? When the car is shut off, a good lot of the crank must be in the oil. Or - when overfilled the return get splashy....It's so strange - maybe 4.5 qts is absolute max as designed. Where does 4.5 qts end up on the dipstick?
Some of my cars could easily hold 1 qt extra, no issue.
Some of my cars could easily hold 1 qt extra, no issue.
Well then tell me why it doesn't do it when the level is perfectly at 4.5quarts and tell me why I don't get valvetrain clatter when it is properly filled with the right amount?
You guessed it, I am not getting air into my oil system which passes thrby the oil pressure sender causing it to flick and the lifters to clatter.
When the oil is at the proper level none of these occur.
I suspect for an OHV engine, that has less oil in the topend than a DOHC engine, overfilling may be more of an issue.
I recall a post or article about the Ford Duratec V6 having less than 1/2 quart of oil in the sump at high RPMs as the oil had been pumped into the cylinder heads and could not drain down fast enough.
There are lots of posts about folk who experience oil starvation failures during high RPM right hand sweeping turns in Contour and New Cougar websites.
The "workaround" is an additional quart of oil in the crankcase.
Some engines will pump a good quantity of oil into the top end. These probably will not suffer from an addition quantity of oil. That quantity may vary.
Others, may have a shallow pan and not put so much oil up top during operation, and are more succeptible to oil frothing due to overfilling.
As with anything else, your mileage may vary. There is no one size fits all advice.
I recall a post or article about the Ford Duratec V6 having less than 1/2 quart of oil in the sump at high RPMs as the oil had been pumped into the cylinder heads and could not drain down fast enough.
There are lots of posts about folk who experience oil starvation failures during high RPM right hand sweeping turns in Contour and New Cougar websites.
The "workaround" is an additional quart of oil in the crankcase.
Some engines will pump a good quantity of oil into the top end. These probably will not suffer from an addition quantity of oil. That quantity may vary.
Others, may have a shallow pan and not put so much oil up top during operation, and are more succeptible to oil frothing due to overfilling.
As with anything else, your mileage may vary. There is no one size fits all advice.
I'd say 1/2 qt over as I doubt much oil is in the pan during use on some cars..
My friend's hyundai accent is 3.4qt including the filter.
I checked it the other day... it was 1.8qts low
2qt was slightly over full.. thats just scary
She says "It was clattering"
So when you have a 3.4qt sump with 1.6qts total in the engine.. how does it even work?
My friend's hyundai accent is 3.4qt including the filter.
I checked it the other day... it was 1.8qts low
2qt was slightly over full.. thats just scary
She says "It was clattering"
So when you have a 3.4qt sump with 1.6qts total in the engine.. how does it even work?
My 2nd Civic Si (1991) would sort-of remedy the problem itself if I overfilled it. During the course of 3000 miles, it would burn the excess until the dipstick read right on the full mark. If I only filled it to the full mark, that's where it would stay for 3000 miles. In other words, it only used oil if it was overfilled. Strange little engine.
Yeah, I don't know where that quart of oil goes. I think I need to understand how and when to check oil level. After oil change - 5 quarts shows low - then later adding .5 quarts shows 1/2 quarts over full after a while.quote:
Originally posted by Clyde65:
OH21, where is the the extra 1/2 quart comming from?quote:
Originally posted by OriginHacker21:
After a 5,000 mile run - the dipstick reads 1/2quart over full.
Extra 1/2 quart could be a coolant leak somewhere. As already said, it also could be fuel and condensation not being evaporated out of the oil but a 1/2 quart is alot of impurities IMO.
I'm always in favor of 1/2 quart lower rather than a 1/2 higher, due to foaming/aeriation. As already said, where there's air, there's not lubrication. However, I don't see how it affects lifter chatter being overfull because as long as the pump has oil to push up to the top end of the engine, it's being lubed. I've always thought that aeriation affected crank and cylinder lubrication.
Oh screw it.......just run an oil with a buttload of moly and who cares where you're at, right?
I'm always in favor of 1/2 quart lower rather than a 1/2 higher, due to foaming/aeriation. As already said, where there's air, there's not lubrication. However, I don't see how it affects lifter chatter being overfull because as long as the pump has oil to push up to the top end of the engine, it's being lubed. I've always thought that aeriation affected crank and cylinder lubrication.
Oh screw it.......just run an oil with a buttload of moly and who cares where you're at, right?
One of my neighbors is a master mechanic. The best I've ever seen. He says you're OK up to half a quart over. Past that you need to drain a little out.
I'd rather be slightly over-filled. The dipsticks on cars are not extremely accurate measuring tools, so there would be some lee-way either way. But I would definitely just feel better knowing there was more than adequate oil in the system as compared to not enough. I doubt the crank aeration thing is an issue with up to 1/2 qt extra in most cars (some with very small sumps maybe). But maybe 1/2 qt low could starve the engine for oil during hard cornering. My '78 Camaro's oil light always came on when cornering hard if I was at the low end of the dipstick range. If I had it to the very full mark, it wouldn't. I doubt that would be an issue in more moden cars with proper baffling, though.
OriginHacker21,
To be as accurate as possible when checking your oil, it must be done under the same conditions each time. Check the owner's manual for specifics, but usually oil is checked when hot but after the engine has been turned off for 5-10 minutes. I think what you may be doing is checking oil level cold after an oil change, seeing that the specified amount from the book isn't getting it to the full mark, and then adding some more cold oil. Then when you check it some time later when the oil is hot, it has expanded and shows over-full.
Or you could be checking the oil too soon after adding oil during a change. The oil you just added hasn't made it down to the pan, so the dipstick shows low. Adding some more gets it to come up (but it's still some of the original oil that is on its way down to the pan. What you just added hasn't made it there, yet.), and you feel satisfied you have the proper amount. But you may have indeed over-filled it.
For checking oil, I do it the same each time. I add just under specified amount of oil (my car calls for 4 1/4 qts with filter, so I add 4). Just under because I'm quite certain atleast 1/4 qt is still in my engine somewhere from not draining. Then I go for a drive, return, park on very level ground, and shut the engine off. After 10 minutes, I check the level. It is dead on the top line of my dipstick. And I would guess it is still slightly overfilled, but easily within the margin of error of the dipstick.
Double check your owner's manual, because it may have a specified amount of time you must wait for the oil to drain back to the pan in order to get an accurate measurement. It'll also specify if it should be checked hot (probably, I've never seen a car manufacturer recommend checking cold).
Dave
OriginHacker21,
To be as accurate as possible when checking your oil, it must be done under the same conditions each time. Check the owner's manual for specifics, but usually oil is checked when hot but after the engine has been turned off for 5-10 minutes. I think what you may be doing is checking oil level cold after an oil change, seeing that the specified amount from the book isn't getting it to the full mark, and then adding some more cold oil. Then when you check it some time later when the oil is hot, it has expanded and shows over-full.
Or you could be checking the oil too soon after adding oil during a change. The oil you just added hasn't made it down to the pan, so the dipstick shows low. Adding some more gets it to come up (but it's still some of the original oil that is on its way down to the pan. What you just added hasn't made it there, yet.), and you feel satisfied you have the proper amount. But you may have indeed over-filled it.
For checking oil, I do it the same each time. I add just under specified amount of oil (my car calls for 4 1/4 qts with filter, so I add 4). Just under because I'm quite certain atleast 1/4 qt is still in my engine somewhere from not draining. Then I go for a drive, return, park on very level ground, and shut the engine off. After 10 minutes, I check the level. It is dead on the top line of my dipstick. And I would guess it is still slightly overfilled, but easily within the margin of error of the dipstick.
Double check your owner's manual, because it may have a specified amount of time you must wait for the oil to drain back to the pan in order to get an accurate measurement. It'll also specify if it should be checked hot (probably, I've never seen a car manufacturer recommend checking cold).
Dave
Designed capacity and oil level are two related, but separate concepts. It is nice to know exactly how they are related and then make an informed judgement about how much oil you may actually want to put in.
I have issues on a couple vehicles with drainback from external coolers and bypass filters. One even had the wrong distick in it when I bought it. So with all my aftermarket stuff disconnected I put a stock-sized filter on it, added the specified five quarts, ran it for awhile to warm up and let it sit overnight. In the morning I noted the level on the stick (way under, BTW), cut and welded the stick until it read correctly, re-connected everything and added oil until the proper level + 1 quart over. I figure this is good, because it had been running with about 2 quarts over if the bozo that owned it previously was filling it based on the stick he was using.
I have issues on a couple vehicles with drainback from external coolers and bypass filters. One even had the wrong distick in it when I bought it. So with all my aftermarket stuff disconnected I put a stock-sized filter on it, added the specified five quarts, ran it for awhile to warm up and let it sit overnight. In the morning I noted the level on the stick (way under, BTW), cut and welded the stick until it read correctly, re-connected everything and added oil until the proper level + 1 quart over. I figure this is good, because it had been running with about 2 quarts over if the bozo that owned it previously was filling it based on the stick he was using.
Javacontour, I have read the same thing (probably at contour.org?). I fill up with 6 qt of Mobile 1 every oil change, and in 7 years and 119k miles, not a problem. With the engine anyway.
But the people who say it depends on the vehicle are right. In theory, over is better than under since there is more oil to disperse the heat and contaminants, and more oil to "dilute" the shearing, etc., that occurs. But if the vehicle in question can't take it, it can't take it.
But the people who say it depends on the vehicle are right. In theory, over is better than under since there is more oil to disperse the heat and contaminants, and more oil to "dilute" the shearing, etc., that occurs. But if the vehicle in question can't take it, it can't take it.
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