Just how bad is overfill?

Messages
263
Location
LA, CA
It seems that everytime I have a dealer or shop change my oil, they overfill by ~0.5quart. On the dipstick, for example, the oil went past the upper boundary by ~3/4". How bad is this? I've read that it can cause foaming of the oil, but is 1/2 quart really going to do that? What can I do to remove some excess oil without getting under the car to drain it?
 

Patman

Staff member
Messages
22,012
Location
Guelph, Ontario
In most engines you should be fine with that small amount over. I wouldn't even bother trying to take some out. Just check your dipstick immediately after you shut the engine off and if you don't see tons of little bubbles, then the oil isn't being aerated and you're fine. A lot of people on here put more oil in their engines than the owner's manual states, myself included. I put an extra 0.4L of oil in my wife's Honda for instance (it calls for 3.6L but I put in 4.0)
 
Messages
47,828
Location
Everson WA - Pacific NW USA
Patman nailed it. There are very few cars (if any) that actually will be harmed by 1/2 qt extra oil. And there may be some evidence that keeping you oil at or very slightly above the full mark is a good thing.
 
Messages
13,132
Location
By Detroit
What does it say in your owner's manual. On my Fords (all '90s) the manual actually says the oil may be above the full mark when brand new or after an oil change. It also shows how high is acceptable in that situation.
 
Messages
950
Location
Loveland, Ohio
When I had a 95 Ranger it had the same wordage about oil level may be high after a change, I never did understand that. It just seemed a little confusing and I've never seen it in any other manual. ???
 
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4,872
Location
MN
Why not make them do it right? Seems to me any place that doesn't check the oil afterward doesn't seem like a good place to go anyway. [I dont know] -T
 
Messages
13,132
Location
By Detroit
quote:
Originally posted by John K: When I had a 95 Ranger it had the same wordage about oil level may be high after a change, I never did understand that. It just seemed a little confusing and I've never seen it in any other manual. ???
I think it is partly because there is some leeway in the acceptable oil level, but moreso because they want to tell you the thing takes 5 quarts instead of 4.5 because a lot of folks might have trouble with that. (You know, half the population is below average in intellegence [Big Grin] ). Likewise, the manual says to wait until the oil is at the bottom of the safe zone and then add a whole quart. But we mathematical oil freaks like to add oil in ounce increments [Smile] and so don't understand the dumbed down owner's manual language.
 
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3,845
Generally speaking, keep the oil level out of the crank so you don't foam it and you should be fine. If you corner hard or drive like Patman, or Jason Troxell, well ... you'll be sloshing a lot of oil all over the place !
 
Messages
7,786
Location
Oklahoma
That's going to happen if they crank up the car right after new oil/filter. The dipstick will appear a little low because they didn't give oil time to drain back into the sump.
 

DaveInLA

Thread starter
Messages
263
Location
LA, CA
Every car owner's manual I've read always states, in bold letters, "DO NOT OVERFILL". It seems that most places just puts in 5 quarts regardless of how much oil is appropriate. I suppose a small amount of overfill isn't too bad, as this car is old and probably consumes a bit more than normal. I think I'll start changing my own oil from now on.
 
Messages
4,872
Location
MN
Yes some places do just use a set amount. They see a Camry so they put in X amount of oil, and let you go. This doesn't account for different engines, options, filter size, drain time, ect. A good place will start the car and check for problems, then turn off the engine and let the oil drain for 30sec-1 minute, and check the dipstick. -T [ March 15, 2004, 03:53 PM: Message edited by: T-Keith ]
 

Kestas

Staff member
Messages
13,983
Location
The Motor City
One documented exception is the Mercedes 320 24V L6. After manufacture there was a tsb issued warning owners to lower the oil charge from 7.5L to 7.0L. It turns out the original level produced too much pressure on the main crank seals resulting in leakage. In fact, some MB owners with other engines reported that if they tried to overfill (or top off the oil), the engine would shed this oil until it reached a steady level. I also vaguely remember somebody posting about other engine makes that exhibited the same phenomenon.
 
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