how low on oil can a standard car get before there is a mechanical problem

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Jun 22, 2016
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How low can I let the oil get before there is a mechanical problem? I am not talking crazy low like you see on youtube where guys try to run on 1/2 a quart. I am talking 1 or so qt low, normal dips you might see between changes. On a 4QT sump my camry calls to add oil when it gets a qt low but would 1/2qt or so lower hurt? I am guessing the thing to avoid is the pump running dry when the oil is being pumped through the system. Maybe the problem would be not enough oil to distribute contaminants. When I drain the oil showning 3 quarts it looks like a lot and the car would be just fine a little lower but what do I know, answer, not much. In my case it gets to about 1 qt low at the end of the change interval and I am always wondering if I should add 1 quart with 500 mi to go or would it even make any difference to the engine.
 
There are other reasons besides mechanical damage why more oil is better than less. I would never under any circumstances operate an engine where the oil level was below the designated “low” mark on the dipstick. Your owner’s manual probably says the same thing.
 
By the title, I thought you were asking about how unrefined an oil can be before anything would be noticed.
 
I would hope that in general the low mark on the dipstick is the lowest you can go while still operating your engine up to redline in average operating conditions safely. obviously there are additional advantages why you want the oil higher on the dipstick with a margin of safety, cooling, and oil longevity being several.

Being a DIY'er that likes to help people out you come across a lot of cars out there with oil not even touching the dipstick. Even some that have already ready started to starve the lifters and cause ticking. After adding oil most of these engine dont display any obvious signs of permanent damage if you caught it before any bearings spin. I've seen engines 3 quarts low in 6 quart systems not display any signs of permenant damage so I think the margin for safety is halfway decent.

As for the lack of piston squirters... Although piston squirters do help lube cylinder walls their main function is cooling the bottom of the piston for detonation resistance. The cylinders walls (in engines without squirters) are primarily lubed by oil slinging off the connecting rod journals, so If you have oil pressure you are lubing the cylinder walls. Windage from oil high in the pan surely plays a factor but isn't the primary lube mechanism for the cylinder walls.
 
My car has an oil monitoring system. It would not give you a warning until you are about a quart low.
Many people were unhappy with that, thinking this is pushing it. So yeah, try and stay within the high/low marks and
1 quart low is not great. Oil lubricates and cools your engine(and turbo if you have it). The lower amount would be circulated
more and see more mechanical, heat and oxidative stress.
On a sharp bend you could even not have enough in the pan for the pump to pass around.
Dont think you did any semi-serious amount of damage, but would not push it, especially
on a turbo or direct injection engine.
I would add the quart at the middle of the interval to stay a bit above the low mark at all times.
 
I'm pretty sure there is a reserve quart in the engine after the level falls off the dipstick. If that wasn't the case, there would be a **** ton of people who would have ruined their engines all ready. Think of all the oil levels you've checked in cars for friends and family. My observation is that 30% of them have the oil level low enough to not register on the stick. I show them, I add oil, and give them a good idea of why they should check their oil level. AND they never listen. Two years later and the engine is still running.
 
I also wouldn't go below 'ADD' on the dipstick if at all possible.

Having said this I will relate this story from my youth....in the mid 70s, while in school, I drove a 1972 Dodge van with the venerable 318ci engine on weekends making deliveries in NYC. I often checked the oil to find nothing showing on the dipstick {because the regular drivers weren't into checking the oil}. I would stop and pick up oil (at AID or RS Strauss) and add 4 qts. to bring it back into the crosshatched area. That van was sold to a guy with a poultry store on the same block who ran it for many more years. Those old American iron engines could 'take a lickin and keep on tickin'...I'm not so sure you would be so lucky with a modern DOHC aluminum engine.
 
I also wouldn't go below 'ADD' on the dipstick if at all possible.

Having said this I will relate this story from my youth....in the mid 70s, while in school, I drove a 1972 Dodge van with the venerable 318ci engine on weekends making deliveries in NYC. I often checked the oil to find nothing showing on the dipstick {because the regular drivers weren't into checking the oil}. I would stop and pick up oil (at AID or RS Strauss) and add 4 qts. to bring it back into the crosshatched area. That van was sold to a guy with a poultry store on the same block who ran it for many more years. Those old American iron engines could 'take a lickin and keep on tickin'...I'm not so sure you would be so lucky with a modern DOHC aluminum engine.
I knew a guy in high school who had a 318 and he would wait until it started knocking, then he would dump in 5 quarts. Claimed he had been doing that for 20k without issue.
 
if your oil light isn't on then I think you are fine. This is not my practice, preference or recommendation but if the engine has oil pressure you are good to go IMO.

just my $0.02
 
I add oil to my cars with a 4 qt. capacity when they get 1/2 qt. low. It's probably not necessary but I figure it doesn't cause as much wear and tear on the oil because of having a lower volume. If I were going to let it go to a qt. low and was near an oil change I'd just change the oil early rather than add a qt. to run a few hundred miles. If you added a 1/2 qt. when it got 1/2 qt. low it would likely still be in the safe range when it was due for an OC.
 
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If you have got a car that leaks or burns oil.. check the oil level often.

May want to add a little more before a long trip, or even regular driving, to match for the rate of loss.
 
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