What is the optimum oil level in a modern car engine?

Question

A guy at work was talking about oil levels in his car (a 6-cylinder Toyota Solara or something). He was mentioning that he prefers to keep the oil level a bit above the "add oil " mark on the dipstick. He said that the engine operates more efficiently that way, and that as long as the oil remains clean and changed often it isn't a problem. I however prefer to keep my oil near the top of the normal range (which seems to be what everyone does when they change the oil). What is the optimum level? Assuming that my work friend doesn't have problems with oil leaking or the engine overheating, is there any advantage to his way (or is he trying to save on oil????)

Answer 1

It depends a great deal on what kind of car you are dealing with. If it is a new car, less than two years old and less than 20K miles on the odometer, you would best keep the oil level very close to the dipstick FULL mark. If it is a high mileage older car, you might be wise to switch to a thicker, higher viscosity oil to be aware of any slight oil consumption. Most people today are using multi-grade engine oils, but there are so many new products available, it is always safer to read up on what your car's manufacturer recommends. In the winter or cold weather area, a high quality multigrade 5W-50 is usually adequate. In the summer or warm climate areas, you might find 20W-50 oil a useable choice. If the engine is burning a little oil, or if there is the slightest leak, oil checks and oil changes need to be more frequent. Please note, that oil changes at 3000, 5000, 7500, and even 10,000 mile intervals are no longer considered necessary when using the new multiviscosity brand name motor oils. Yes, any oil change should see a new oil filter installed at the same time as an oil change. A minimum oil change should be performed once per year, regardless of the miles driven. No, it is best never to overfilll the the crankcase with any kind of oil, but yes, always keep the oil level above the ADD OIL Mark. Overfilling the crankcase with any kind of oil has the tendency to splash excess oil on the cylinder walls which will be drawn into the combustion chamber by the intake manifold vacuum almost any time the engine is operated under light load.

Answer 2

Depends how much too much you put in. Is it like less than like 1/2 quart? If so leave it alone. If you have added 4 quarts because you though the line on the dipstick represented the entire engine oil capacity then you need to drain out some. The real problem is foaming. The oil level is too high, the crankshaft whips up the oil to a foam and then it cant lubricate.

Answer 3

I suppose keeping the oil level at the low end of normal could mean less drag on the crankshaft (in theory), but the oil also has a cooling effect on the engine as well as lubrication. If oil is helping to carry heat away from critical areas and you reduce the VOLUME of coolant (oil) you will not be carrying away heat as efficiently.

Also, if your oil level is low, there is the possibility of the oil pump pickup becoming exposed to air (instead of oil) and starving your bearings for lubrication when operating your vehicle at extreme angles.

In my opinion, the negatives outweigh the positives.

Answer 4

the amount of oil you put into your engine should be the amount that your owners manual tells you, it is printed in black and white for a reason, that is what the manufacturer recommends. 10 times out of ten that amount will be the same as the full mark on the dipstick. Of course those that feel they know more about their car than the ones that made it, will always do what the see fit.

Answer 5

Top of the "normal" range is fine. Adding more than recommended could foul the catalyst, which costs some bucks to replace.

It's unclear to me what positive impact another half-quart of oil would have on efficiency in any case.

Answer 6

there is a saftey margin built in to the dipstick markings on your car -anywhere between the marks indicating full and low is great and does not affect the operation or life expectancy of the car's drive train at all

It is like asking ..i am supposed to drink between 50 and 51 glasses of water a day is it better to drink 51.01 glasses or 50.29?? it is so little as to make no difference - check the manual and do as it says..

Answer 7

the guys a fruit, it should be to the full mark, where it is when the oil's changed. he's talking about keeping the oil down to prevent sloshing against the crank which is absurd . he's not driving a race car, its a production car.

Answer 8

It comes down to opinion:
Too much and the moving bits have no room to move and it damages the engine.
Too little and the lifters can screw up

I personally would keep it at normal level. Because as it heats up the oil will expand.

Answer 9

drugs mabye, anywhere in the operating rage is fine but it should stay full, overfilling will cause damage to the engine seals while underfilling will waer out parts in the engine.