How low can you go?

Yuk

Messages
883
Location
Edmonton, AB Canada
As far as I know almost all automotive dipsticks indicate a 1 quart/litre, oil level, top-up range. Can one assume that as long as the crankcase level is always above the lower of the two marks that the engine will operate safely? Does allowing the oil level to drop to the lower mark, before topping up, cause engine damage?
 
Messages
18
Location
Wellington
I've let the oil level go below the bottom dipstick mark before and got away with it.I think theres a bit of a safety margin built in by most engine makers.Not something i would do on purpose though.
 

Patman

Staff member
Messages
22,017
Location
Guelph, Ontario
Running at the low level is definitely dangerous if you drive the car hard, especially if you do a lot of hard cornering. You can starve the engine for oil. Always top off the oil when it needs it, don't wait until it's at the lowest point on the dipstick. I like to run a bit more oil than the rated capacity in my cars actually.
 
Messages
38
Location
Australia
Unless you car has a poor sump design or weak pump, no damage should occur as long as it's above the bottom level on the dipstick. Well designed engines can even go below that level and still not be damaged. On the other hand, over filling can lead to as many problems as under filling on some vehicles, so beware of that as well. The safe range is always within that marking on the dipstick, so in the end it pays to do what you need to keep the oil level in that range.
 
Messages
507
Location
Tennessee
I had a mechanic friend with a 300 ci Ford straight six in a pickup. He would run it 4 quarts low before refilling. [Eek!] He said this is the only engine that could do this. And yes, I actually saw this while towing a race car. It had a leak at the time, and would use 4 quarts between fill-ups. He refused to stop between fill ups.
 
Messages
3,031
Location
Florida
Why? If you take the time to check the dipstick doesn't it make sense to keep the oil at the full mark? Daily Drives: -2003 Toyota Tacoma PreRunner XtraCab, 2.7 Liter , Mobil1 Synthetic SS 5W-30. ODO 9800 Miles. -1995 Toyota 4-Runner 3.0 V6, Mobil1 Synthetic SS 10W-30. ODO 91800 Miles. http://community.webshots.com/user/amkeer
 
Messages
780
Location
Palatine IL
I'm with Patman. Even if you don't drive hard, you may need to corner hard in an emergency and you don't want starvation. I'm aware of a few motors that need to be overfilled 1 qt for spirited use to eliminate starvation. I suspect there aren't many cranks that spin within 1/2" of the oil at the top mark and an extra qt shouldn't hurt most motors that have at least a 4 qt capacity. I'm not suggesting that everybody over fill but the bottom mark could be bad at times.
 
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1,565
Location
palm beach
honda says to not top off the oil in a engine or transmission untill/unless it gets below the lower mark. this is what is in my manual. why this is? i think that the "low" mark on a honda dipstick is infact, the low mark of the "high range" of the maximum ammount of oil. perhaps "low" means "the low part of high" if you know what i mean. otherwise, i cant see any other valid reason for NOT keeping the sump full to the high mark on the dipstick. so basically, a 4 quart oil change brings the dipstick halfway between high and low, and that is where i leave it. it causes no problems, and the engine burns no oil whatsoever in my oci.
 
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5,358
Location
Gone
quote:
Originally posted by cryptokid: i think that the "low" mark on a honda dipstick is infact, the low mark of the "high range" of the maximum ammount of oil. perhaps "low" means "the low part of high" if you know what i mean.
ck, You have inspired me...personally I think the bottom mark on the dipstick should be viewed as representing one sigma from the mean or in other words it could represent the low end of the high regime or maybe the high end of the low regime in which case it would be statistically significant only to the point that the sump itself was manufactured to an accuracy of no more than one standard deviation from the target capacity...if you know what I mean. [Wink] [Cheers!]
 
Messages
2,635
Location
Chicago
I had a '94 Dodge Caravan with a 3300 V6 and currently have a '98 Chrysler T&C with a 3800 V6. Both said in the manual to add 4.5 quarts of oil with a filter change. When you do this the dipstick indicates 1/2 quart low. I figure the company that made the vehicle must know how much oil to put in so I run from 1/2 quart low to a full quart low and then add 1/2 a quart of oil. Total miles on both engines are 290,000 and not a spec of trouble. I run 10,000 miles on Mobil 1 5w30 and Purolator Pure One filters.
 
Messages
4,630
Location
Decatur AL USA
quote:
Originally posted by Patman: Running at the low level is definitely dangerous if you drive the car hard, especially if you do a lot of hard cornering. You can starve the engine for oil. Always top off the oil when it needs it, don't wait until it's at the lowest point on the dipstick. I like to run a bit more oil than the rated capacity in my cars actually.
General assumptions such as this can be dangerous. Some engines such as the DOHC 2.0L Chrysler require the oil level to be run lower not higher for extreme duty use such as Auto-X or Open Track events. Mopar Performance recommended 1/2-1 qt below rated capacity. When run at full capacity (or worse overfilled), high rpm, and high cornering loads you would aerate the oil which could cause engine failure. I have always wondered if the full mark on the stick actually means full or does it mean maximum? In which case would halfway between maximum and minimum not be best? Just something to think about. Gene
 
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