Should I do this for 1st oil analysis?

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Dec 10, 2002
I have put 1200 miles on my car in the past four months. I know the oil is still good but I checked the dipstick yesterday. I'm down 1/3 quart. Should I add more oil to bring up the dipstick to full or should I let it burn till the low level of the dipstick then drain the oil for oil analysis? I know if I add oil, it will dilute the batch I have in there now. Since this is my first oil analysis, I want to know how much silicon I have in there since I put a KN air filter last year. opinions?
It seems to me that if the Si is small enough to stay in the oil instead of being filtered out, it is likely to go out with the consumed oil.

Even if that is not the case, either way it's only a 20% difference say 12 instead of 10. At any rate, you should establish a routine and follow that routine during all intervals so that the trending will stay correct.

Personally, I wait until it's a quart low to add oil, but it's a personal choice.
Either add oil or take the sample now. I personally would add oil (just keep track of additions). You can allow for dilutions.
My habit is to add oil in small amounts as often as it needs it. My LT1's dipstick has holes in it to see where the level is at, and as soon as I see one hole empty, I top it up with 100ml of oil. Consistency is the key, if one oil change you do something different, it's harder to compare the results accurately.

The problem with letting the oil go down a quart, or even half a quart before topping up, is that you reduce your total amount of oil, and put more stress on the remaining oil. A half to one quart out of a 4 quart sump is a pretty significant amount IMO.
A) If it is low add oil

B)I guess the only exception is for a grossly inaccurate test it would have you been adding oil to an engine crankcase that was essentially empty.

C)I am about to my 1st ever oil analysis for Mobil 1 5W30 SuperSyn. If you are using the Blackstone thier is a section of the form that asks for how may quarts of replacement oil (they a use a certain term) you have added since the last change.

D)Based on that it would be my logical conclusion they recalculate and or pro-rate oil life conditions based on the dilution amount?

E)In my case i will have a situation with 1.2qts being my interim fill or about 20% relatively new oil to 80% old.

I have a 1.5 Liter engine. So I better add that oil. I never thought about the stress on the oil when it is low or the engine. I thought maybe my oil analysis wouldn't be as accurate. I'll tell blackstone that I added oil. I guess I should add the same brand and type of oil? my capacity is 4 quarts. oil change takes about 3.3 quarts. so even a third of a quart burnt takes alot. I have noticed for the past year or so my gas mileage has gone down the pits too. I don't know if it is the winter gas so I want to find out about that from the analysis. From 360 miles a tank to 275. will I get a recommendations from blackstone on abnormal readings?
Always add the same brand and viscosity when topping up the oil, especially if you're doing oil analysis on it.

And like I said, it's better to top it up a little bit at a time all along, because in addition to being better for the engine by not running the oil low, it makes for more consistent oil analysis results. If you waited until it was a quart low, then added a quart and 1000 miles later you sampled it, it wouldn't be as true of a representation of that oil's performance as if you had topped up that same quart of oil over a longer period of time earlier on in the interval.

[ February 12, 2003, 01:10 PM: Message edited by: Patman ]
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