Oil Analysis

The machine testing units are highly dependent on how well the tech cleaned it out after the previous sample. Just the slightest residue will skew the results on the next sample. When cleaned and operated properly, the machine units are not bad. I would have the shop take two bottles of samples. If the machine shows something out of whack, then send the other bottle into a lab and have them test it and see what they find.

I have no problem with the machine units doing a quick testing. They are not as thorough as a lab, but they work in a pinch. The key to any oil sampling is history. You want to be able to see numerous results and compare them. That is how you can really tell if something is becoming a problem. An oil lab will show the current sample, and a few of the previous ones, and also show a graph of how the samples are trending.

Each way has a useful place. It just depends on how meticulous you want to watch the used oil samples. And the machine will give you "while you wait" results, whereas it will be several days before you get lab results back. If one doesn't mind shelling out the money, having both done is probably not a bad idea. You can catch something really critical via the machine and get it looked at right away. And the lab samples will give you a solid trend line graph to see how your engine is holding up over time.

There is no perfect solution here. It is up to each person how they want to do it.