Accounting for makeup oil in UOA

[TallPaul]

Reference following scenarios:


1. Inital fill to full mark on dipstick. Drain when half a quart low. When reporting makeup oil to lab for UOA do I need also to tell them it was half quart low when I drained it?

2. Initial fill 12 ounces over full mark on dipstick. When reporting makeup oil to lab for UOA do I count this initial overfill as makeup oil (it is in effect advance makeup oil)?

3. Combine #1 and #2.

 

[blackdiamond]

I would say that it would take someone like Terry Dyson to really gain anything from this "additional" information, but I'm sure it does have some impact on a used oil analysis.

The question should be if the oil capacity of a vehicle is incorporated into the results of if it is simply based on the sample provided.

Makeup oil would be a contributing factor for additives and things like TBN, but I doubt it would really be possible to have any real "finding" with it's relationship to wear metals.

The amount of makeup oil, if deemed important, would also need the time that it was added for a true analysis. Pouring in a quart in the last week would be significantly different than pouring 1/4 quart in four times during the OCI.

 

[Quattro Pete]

It doesn't really matter. The lab doesn't use this info to come up with ppm numbers.

The only way they may be interested in it is to tell you that you have an oil consumption issue, but that you can kind of figure out by yourself anyway.

 

[BobFout]

It's useful if you can apply the ratio in pro-rated fashion to wear numbers.

40 pmm Fe over 10K miles with the original 4.5 quarts vs. 40 ppm Fe over 10K miles having added a quart at 7K miles. Factor in the extra quart and the 3K miles on that quart...