Re: oil level reading - simple logic

Ha Ha Ha you are a joke. The purpose of checking oil as the manufacturer recommends is to keep the oil from getting dangerously low.

If however you want to do what the OP is attempting: to accurately determine the rate of consumption it is not going to produce accurate results if you base it on a bunch of dipstick readings at the gas pump every few hundred miles. Even the OP wasn't that stupid.

-jim

I think we are in semi-agreement about the inaccuracy of determining oil usage via repeated dip stick readings. I think it is far to imprecise to yield repeatable results, but that is just my opinion.

I haven't owned a road vehicle since the 80's that used enough oil between changes to cause a problem (and even then, it was only a British vehicle that used a lot of oil). But If I develop a desire to figure out precise oil consumption for a particualr vehicle I think I'd do the following:

1. Find a dead level spot and park the car in an easily repeatable position (heck I might even mark the tire locations). Let the car sit overnight if possible. Record the vehicle's mileage.
2. Drain the oil completely (let it sit for at least an hour). Remove the old filter.
3. Reinstall the drain plug
4. Weight the new filter, record the weight of the new filter, then install the new filter.
5. Weight each bottle of new oil before pouring it into the engine. Weight the bottle after the oil is poured into the engine. Substract empty bottle weight from full bottle weight and record the weight of oil added to the engine. Repeat for each bottle. Record the total weight of oil added.
6. Start the engine and check for leaks.
7. Allow engine to cool and sit for an extended period of time. When satisfied the oil has drained back to the oil pan, pull the dip stick and scribe a line to indicate the "full" level.
8. Drive usual pattern and check the oil level at least weekly. Monitor the change compared to the scribed line as a precaution. Don't add any oil.
9. Plan to change the oil whenever the level dropped to the "add" level or at the normal oil change interval (whichever occurs first).
10. When it was time to change the oil (based on step 9), park back in the prior spot (step 1). Let the car set in that spot overnight if possible. Record the vehicle's mileage.
11. Weigh oil catch pan.
12. Drain the oil into the pan. Let it drain for at least an hour.
13. Remove the filter carefully and try not to lose any oil (but have the drain pan underneath to catch as much as possible should any spill).
14. Pour as much oil as possible from the filter into the drain pan - allow to drain for an extended period.
15. Weigh the pan of oil. Subtract the empty pan weight from the full pan weigh and record the weight of oil.
16. Weigh the filter. Substract the origianal weight (step 4) from the used filter weight. Assume this is mostly oil and add to the weight of oil from step 15.
17. Have a sample of oil analysed.
18. Subtract out any moisture, antifreeze, solids, etc. listed in the oil analysis report from the total weight of used oil (step 16).
19. Subtract the adjusted weight of used oil (step 18) from the weight of new oil added (step 5). This is roughly equivalent to the oil consumed over the period. Convert this to quarts (or whatever) and divide by the mileagae interval (mileage recorded in step 1 minus the mileage recorded in step 10).

This is about as accurate a method as I could come up with. Will I ever do it? Probably not. It actually seems insanely complex for a single person / single measurement, especially considering a precise measurement of oil consumption for a particualr vehicle is of little practical value. If I have a car that uses so much oil I need to be concerned, I am going to get rid of it. I have farm tractors that use

1 or 2 quarts a day when working hard (but they hold 20 quarts). I just add as necessary. The usage is completely unpredictable. For some jobs the APPARENT oil consumption is negligible. For other it is dramatic. Ususaly I check the oil once in the morning and again at lunch time. Sometimes I have to add a quart both times, sometimes neither. If the oil usage gets really bad, time for a rebuild. Really bad in my opinion would be 2 quarts in 4 hours of hard use.

Ed

Repeated dipstick readings is like counting all the legs and tails in a herd of cattle. It could get you the same result as counting heads, but the chance of introducing error is significantly greater.

It sounds like it should be accurate , but you didn't have the scale certified and you didn't check the air in the tires :)

I've driven oil burners in the past and you don't need to be excessively anal to figure out the rate of consumption fairly close. I drove a car that burned a quart every 600 miles for about 10 years. I could predict within 20 miles when it would be at the ADD mark (checked cold). The first quart after an oil change would go 800 miles but that was mostly because filling it with 5 quarts brought it up to about 1/4 quart over the full mark.

Fifteen years ago you could get a 2-1/2 gallon container of oil for 6-7 bucks. That was enough to change the oil and keep it filled for about

3800 miles. Driving an oil burner today would be expensive.

-jim

er, the joke is on you asshole - you don't understand why though evidently.

no, it's for recreation!!!

so where are your numbers, asshole?

Bingo!

The public has been dumbed down to the extent that constant hand-holding is normal procedure...

JT

On 6/10/2010 12:22 PM jim spake these words of bullshit:

Once again you put me in the unenviable position of agreeing with beam. For that alone, you deserve to roast.

In point of fact, keeping track of the amount of oil you have added from point a to point b, whether those points are distance or time, gives you the total oil consumption for that period.

That doesn't change whether you check the dipstick level once or a 100 times.

Grow up or shut up, kid. Or at least try thinking before you type.

RFT!!! Dave Kelsen