Keep the oil level above the add mark and either at the full mark or as close as possible to it.. The upper half of your engine will thank you by not picking your pocket.
Don't constantly top off an engine that burns oil?
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When I change the oil, I usually shoot for the 1/2 to 3/4 region on the dipstick. About the only time I get up to the full mark is when I'm trying to drain a quart.
I don't add until the "add oil" line. On my Lincoln, I have to have a funnel to keep from making a mess. Since I almost always am checking my oil at a gas station and am at the mercy of them having disposable paper funnels(I really should start carrying one) I tend to put it off until I'm at the "add" line.
My MG is a bit interesting in terms of oil. It's more of a leaker than a burner(it's British), but I've noticed that oil consumption does definitely go at higher levels. It has a negative crankcase ventilation system(the bottom of the crankcase goes directly into vacuum ports on the carbs) and I've noticed that at higher oil levels oil will get slung out of the vent of its own accord if a vacuum home is disconnected. I also sometimes notice a pronounced oil burning smell when the oil is near the top. It will seem to maintain the oil level virtually indefinitely at just a shade below the "add" mark, so that's often where I leave it. Since British car owners are hard-wired to look at our oil pressure and temperature gauges more often than the road
I don't worry so much about it sitting there as long as the oil pressure is normal(and yes I know normal for the car under a wide variety of conditions).
I don't add until the "add oil" line. On my Lincoln, I have to have a funnel to keep from making a mess. Since I almost always am checking my oil at a gas station and am at the mercy of them having disposable paper funnels(I really should start carrying one) I tend to put it off until I'm at the "add" line.
My MG is a bit interesting in terms of oil. It's more of a leaker than a burner(it's British), but I've noticed that oil consumption does definitely go at higher levels. It has a negative crankcase ventilation system(the bottom of the crankcase goes directly into vacuum ports on the carbs) and I've noticed that at higher oil levels oil will get slung out of the vent of its own accord if a vacuum home is disconnected. I also sometimes notice a pronounced oil burning smell when the oil is near the top. It will seem to maintain the oil level virtually indefinitely at just a shade below the "add" mark, so that's often where I leave it. Since British car owners are hard-wired to look at our oil pressure and temperature gauges more often than the road
I'm going to add to the posters who said it depends upon the reason for the consumption. My 89 Accord consumed some oil since brand new. As time passed the consumption increased a bit. When using ST 10W-30 synthetic I would see a puff of blue smoke upon cold start. Hondas of that vintage often lost a bit of oil past the valve guides. I switched to Rotella T6 5W-40 and the consumption slowed to a half-quart every 2,000 miles. In retrospect, M1 high mileage probably would have worked, too. (or, any HM synthetic for that matter) In my case, though, oil level never showed a noticeable difference in consumption. I would just add the half-quart when the level dropped to halfway between "full" and "add." If the issue is PCV or ring related the level may very well make a difference in the rate of consumption. The operative phrase here is YMMV.
One thing that comes into play is crankcase windage. The lower the level, the less oil picked up a slung by the spinning crank as windage. That's why windage trays and screens. To keep the oil level high enough for safety without the crank picking it up and over-oiling the cylinder walls and such...
So a poor mans windage tray is to run one qt down at the add mark. Drag Racers have been doing this for years as it reduces parasitic drag and loss of effective octane by having less oil in the combustion chamber (race motors run bigger ring end clearances so they tend to transmit oil to the chamber).
But, OTOH it also puts more heat into smaller volume of oil so the oil breaks down faster. That's a bad thing. The designers of passenger car motors know they will seldom see high RPM, so they run the oil level high for safety on hills and off camber corners and such.
Trucks and most race motors run big pans with 8 & 10 qt systems so they do not need as much "altitude" to keep a safe volume of oil in the sump. Low hood (bonnets) on cars for low drag and styling means there is less vertical space for pans (sumps) to have ground clearance, so passenger car engines are a big compromise...
Run it where you feel safe. But running low can be problematic if you live in hill country ...
So a poor mans windage tray is to run one qt down at the add mark. Drag Racers have been doing this for years as it reduces parasitic drag and loss of effective octane by having less oil in the combustion chamber (race motors run bigger ring end clearances so they tend to transmit oil to the chamber).
But, OTOH it also puts more heat into smaller volume of oil so the oil breaks down faster. That's a bad thing. The designers of passenger car motors know they will seldom see high RPM, so they run the oil level high for safety on hills and off camber corners and such.
Trucks and most race motors run big pans with 8 & 10 qt systems so they do not need as much "altitude" to keep a safe volume of oil in the sump. Low hood (bonnets) on cars for low drag and styling means there is less vertical space for pans (sumps) to have ground clearance, so passenger car engines are a big compromise...
Run it where you feel safe. But running low can be problematic if you live in hill country ...
Originally Posted By: fdcg27
There is no reason to add oil as long as the oil level remains above the add line.
How about this one. If your oil level is up near the max line, you have more oil in the engine. This means there is more oil to absorb the stresses and energy the engine puts into it. If the oil level is at the 'add' or 'min' mark, you could have anything up to 20% of the oil charge missing, so the remaining oil has to work 20% harder as it circulates 20% more often through the engine, getting 20% more exposure to heat, contamination, shear etc.
There's a reason to keep your oil topped off. Plus, every time you top up you are adding a shot of fresh additives and base oil, like a shot in the arm for the oil.
I'm not saying the other arguments aren't valid, just offering a counterpoint for consideration.
There is no reason to add oil as long as the oil level remains above the add line.
How about this one. If your oil level is up near the max line, you have more oil in the engine. This means there is more oil to absorb the stresses and energy the engine puts into it. If the oil level is at the 'add' or 'min' mark, you could have anything up to 20% of the oil charge missing, so the remaining oil has to work 20% harder as it circulates 20% more often through the engine, getting 20% more exposure to heat, contamination, shear etc.
There's a reason to keep your oil topped off. Plus, every time you top up you are adding a shot of fresh additives and base oil, like a shot in the arm for the oil.
I'm not saying the other arguments aren't valid, just offering a counterpoint for consideration.
Generally speaking, with the taxis, we didn't add until it needed half a litre or more. Anything less was just a pain in the behind, and given the usage pattern, it was best to not let them get too low, lest the thing go on and out of town trip and events get away on one.
Originally Posted By: weasley
Originally Posted By: fdcg27
There is no reason to add oil as long as the oil level remains above the add line.
How about this one. If your oil level is up near the max line, you have more oil in the engine. This means there is more oil to absorb the stresses and energy the engine puts into it. If the oil level is at the 'add' or 'min' mark, you could have anything up to 20% of the oil charge missing, so the remaining oil has to work 20% harder as it circulates 20% more often through the engine, getting 20% more exposure to heat, contamination, shear etc.
There's a reason to keep your oil topped off. Plus, every time you top up you are adding a shot of fresh additives and base oil, like a shot in the arm for the oil.
I'm not saying the other arguments aren't valid, just offering a counterpoint for consideration.
Oil helps cool an engine as well as lubricate it. Run a 5 quart sump down around a quart that's about 20% less oil to help cool and lubricate. Like I said if I went through the bother to pop the hood and the engine needs 1/2 a qt of oil I'm adding it. If I have an open bottle of oil with only 8 ounces in it, I'll add 8 ounces if the engine needs it. That gets that bottle empty into the recycle bin freeing up space. Win win.
Sure a 5 quart sump can run a quart low, I see no reason in doing so. Especially when I have the hood open to check.
Originally Posted By: fdcg27
There is no reason to add oil as long as the oil level remains above the add line.
How about this one. If your oil level is up near the max line, you have more oil in the engine. This means there is more oil to absorb the stresses and energy the engine puts into it. If the oil level is at the 'add' or 'min' mark, you could have anything up to 20% of the oil charge missing, so the remaining oil has to work 20% harder as it circulates 20% more often through the engine, getting 20% more exposure to heat, contamination, shear etc.
There's a reason to keep your oil topped off. Plus, every time you top up you are adding a shot of fresh additives and base oil, like a shot in the arm for the oil.
I'm not saying the other arguments aren't valid, just offering a counterpoint for consideration.
Oil helps cool an engine as well as lubricate it. Run a 5 quart sump down around a quart that's about 20% less oil to help cool and lubricate. Like I said if I went through the bother to pop the hood and the engine needs 1/2 a qt of oil I'm adding it. If I have an open bottle of oil with only 8 ounces in it, I'll add 8 ounces if the engine needs it. That gets that bottle empty into the recycle bin freeing up space. Win win.
Sure a 5 quart sump can run a quart low, I see no reason in doing so. Especially when I have the hood open to check.
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