Mix 3 Very Low Mile Samples?

[miraCRD]

Have a car that'd been minimally used for the past three years, so only was putting about 300-500 miles a year on it, but was changing the oil annually. I have three separate oil samples from each change that I never sent in. What's the thinking on mixing them well and combining them into one sample for a used oil analysis? All three changes were the same exact brand, type and viscosity of oil. Would the combined "sample" be reflective of the cumulative miles on all the samples from a wear (metals) standpoint? Three ~500 miles samples = ~1500 miles of use? Or, am I completely defeating the purpose of a used oil analysis by doing this? My thinking is that 300-500 mile oil samples just isn't enough miles to really show much individually.

 

[TmanP]

It certainly wouldn't show the additive depletion associated with 1500 miles of use, and might not show anything useful about wear metals either, but that's a harder question.
Unless you have any reason to expect a problem, I wouldn't waste the time on a used oil analysis of 500 miles, and I definitely wouldn't mix them as it'd be hard to draw any real conclusion from that. If you really wanted a used oil analysis, I'd just send in the most recent sample and call it a day.

 

[miraCRD]

Makes sense...thank you for the input.

 

[himemsys]

If you really want to send a sample in, only send the most recent one, as that will be most representative of what's going on in the engine right now.

 

[paulri]

I think the above advice makes sense. Consider---if there was a problem with sand in the first sample, it would pollute the clear sample that was more recent; likewise, if you do have sand in the latest one only, it would be diluted by a clear sample from the first one or two samples taken.