How come engine oil analysis isn’t more common when buying a used car?

Posted by Fearless-Guide-4484@reddit | Autos | View on Reddit | 12 comments

So an oil analysis can tell you many things about your engine including if it is remotely close to failure. While yes, taking an oil sample, sending it in to get analyzed, and then getting back the results take time, the fastest turnaround time I have seen is 3 days from speeddiagnostix. Not immediate, but if I had to wait 3 days and take the risk that someone else might buy the car I analyzed, I think it would be worth it to get something that I know won’t fail. It's especially worth it if the car is a dime a dozen and average days on lot is long.

This might be harder to do via private party since sellers might feel weird about this, but I think this is not so big a deal with a dealer. For example, just ask the dealer to take the car to get it pre-inspected and ask if they can take an oil sample while they're at it. Then ask the mechanic to take an oil sample and then send it in. Am I missing something as to why this isn’t a more common practice?