By having an oil analysis done, at every change interval, you can monitor metal concentrations and other deposits that could harm your engine. If metal particle levels are too high, this could signal a failure of the rod, main bearings or cam bearings.
An oil analysis will also indicate if there is a high concentration of fuel or antifreeze mixed with the oil. This could indicate failing piston rings or excessive cylinder liner wear.
Oil analysis works best if it’s done over the long term so that samples can be compared. If you consistently see iron, lead and copper particle readings at a low level, you’re OK. But if something goes awry and a contaminant appears, the reading will increase markedly.
Obviously, the sooner you catch it, the better off you are. If you do analysis infrequently and find something, you won’t know how long the problem has existed.”
Maybe the air cleaner isn’t seated properly, allowing unfiltered air into the engine. That will show up in an oil analysis. If you correct it, you may have lost a bit of life in your engine but you probably haven’t destroyed it.
Analysis contains extensive information, but doesn’t focus on only one result, says Maria Burcham, a technical adviser with ExxonMobil Lubricants & Specialties. Instead, look at the overall report. For example, low oil viscosity and fuel dilution might signal a fuel injection system problem. Those results plus high wear metals in the sample might indicate troubles with piston rings or cylinder liners. If your system is starting to fail, you’re going to see multiple indicators that will point you in the same direction.
If you choose to collect the oil sample yourself, don’t take the first drops after opening the drain, which are likely to contain debris. Let it drain for a few minutes and then take your sample. And make sure you note the mileage for the lab.
Also, if you’re adding oil frequently, it can sometimes mask oil analysis wear metal readings. So keep track of how much oil you’re adding.