Let me start with the conclusion: There is great difficulty interpreting the results of oil testing and analysis. I was reading multiple threads and it might be a good time to review this topic. I will try to keep it simple.
Example: One result shows a lead value of 2 while another time it is 10. The later shows “5X more” wear. That seems very bad. In reality a value of 10 is still low. If at first it was 1 then the value of 10 may be “out of control wear?” Really?
Example: You were running a mineral based motor oil. You switched to Red Line. The analysis showed the lead to be 105. OK, now we have an issue. Or do we? Many synthetic oils will clean the residue that is clinging to the inside of your motor. It gives a false elevated level as the lead is not from the bearing but rather from the sludge built up inside the engine compartment. If your engine had minimal wear it would only be evident with serial testing. The next analysis may show a value of 20, then another test brings it down to 10. It may still drop as the engine is further cleaned out. The true wear level may be 2.
Example: You have been using the recommended oil and the analysis always shows the lead to be 0 - 2. Great, no wear. Now you switch to another oil and the value is 10. It’s still not bad but way more than it was. Why? One place few check is the oil you are now using. It’s called a virgin oil analysis. You test the new oil right from the jar, before you put any in your engine. You may find that it comes right from the factory with a lead value of 10. So when you test your used oil 3,000 miles later and the value is 11 then your real value is only 1.
Each lab has it’s own “normal” level for the various tests. Lab accuracy may vary. Proper collection of the sample is important. It should be a mid stream catch from the oil drain plug, an area cleaned off first. It should not be from some tube you forced down the oil stick pipe. You should perform the collection the exact same way each time. Do you change the oil hot, right when you get home from the office or after the car has sat for a few days?
Assuming you are not having something catastrophic going on wear metals generally all rise or decrease as a group to a certain extent. In oil testing, over many decades, the thing that has made very little difference in my cars was viscosity. The thing that was an obvious detriment was dirty air. Dust ingestion pollutes the oil with a sort of sand paper like property. The effect was essentially linear. Double the dirt in the oil, you double the wear. Mind you it was still always very low but the results were compelling.
I have on occasion changed the oil without changing the filter but I change the air filter with OEM replacements. And I do so twice as often as recommended. My engines have always had very little wear so why do I care. I just like doing experiments.
AEHaas
Example: One result shows a lead value of 2 while another time it is 10. The later shows “5X more” wear. That seems very bad. In reality a value of 10 is still low. If at first it was 1 then the value of 10 may be “out of control wear?” Really?
Example: You were running a mineral based motor oil. You switched to Red Line. The analysis showed the lead to be 105. OK, now we have an issue. Or do we? Many synthetic oils will clean the residue that is clinging to the inside of your motor. It gives a false elevated level as the lead is not from the bearing but rather from the sludge built up inside the engine compartment. If your engine had minimal wear it would only be evident with serial testing. The next analysis may show a value of 20, then another test brings it down to 10. It may still drop as the engine is further cleaned out. The true wear level may be 2.
Example: You have been using the recommended oil and the analysis always shows the lead to be 0 - 2. Great, no wear. Now you switch to another oil and the value is 10. It’s still not bad but way more than it was. Why? One place few check is the oil you are now using. It’s called a virgin oil analysis. You test the new oil right from the jar, before you put any in your engine. You may find that it comes right from the factory with a lead value of 10. So when you test your used oil 3,000 miles later and the value is 11 then your real value is only 1.
Each lab has it’s own “normal” level for the various tests. Lab accuracy may vary. Proper collection of the sample is important. It should be a mid stream catch from the oil drain plug, an area cleaned off first. It should not be from some tube you forced down the oil stick pipe. You should perform the collection the exact same way each time. Do you change the oil hot, right when you get home from the office or after the car has sat for a few days?
Assuming you are not having something catastrophic going on wear metals generally all rise or decrease as a group to a certain extent. In oil testing, over many decades, the thing that has made very little difference in my cars was viscosity. The thing that was an obvious detriment was dirty air. Dust ingestion pollutes the oil with a sort of sand paper like property. The effect was essentially linear. Double the dirt in the oil, you double the wear. Mind you it was still always very low but the results were compelling.
I have on occasion changed the oil without changing the filter but I change the air filter with OEM replacements. And I do so twice as often as recommended. My engines have always had very little wear so why do I care. I just like doing experiments.
AEHaas