The Difficulty with Oil Analysis Reports

Messages
1,420
Location
Sarasota, Florida
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
 

OVERKILL

$100 Site Donor 2021
Messages
46,079
Location
Ontario, Canada
Yes, Doug Hillary wrote an excellent article on the utility of Used Oil Analysis that is featured on the main page of the site:
 

OVERKILL

$100 Site Donor 2021
Messages
46,079
Location
Ontario, Canada
One thing that Terry Dyson always used to say was that you shouldn't necessarily worry about the actual wear numbers you are getting as much as you should be looking at multiple reports for your car and keeping track of the trends.

Yup, Doug mentions that in his piece as well. This is what is done with industrial equipment, the data is trended and then anomalies that may warrant further investigation stand-out. Of course the utility of doing this on a comparatively inexpensive passenger car where the lubricant in use, and thus the chemistry, may shift significantly between changes may be questionable. I think some people use it more for a hobby than anything.
 
Messages
1,689
Location
Richmond, VA area
I use them to graph trends which seems to be the value of them (at least to me). Interesting when you do!
Capture.JPG
 

Patman

Staff member
Messages
22,005
Location
Guelph, Ontario
I think some people use it more for a hobby than anything.

In the beginning I thought it might help me tell the difference in wear between one brand of oil and the next, but it didn't last long before I realized that you really can't use UOAs to tell you that. But I've always enjoyed seeing how the different oils I've tried have performed (getting excited when certain oils hold their viscosity over long intervals for instance!) I never really expected that UOAs were going to warm me of impending doom, however they did help me with my old 2006 Civic when I had a leaky injector. The high fuel % in the UOA pointed me in that direction.
 
Messages
5,626
Location
Atlanta,GA
In the beginning I thought it might help me tell the difference in wear between one brand of oil and the next, but it didn't last long before I realized that you really can't use UOAs to tell you that. But I've always enjoyed seeing how the different oils I've tried have performed (getting excited when certain oils hold their viscosity over long intervals for instance!) I never really expected that UOAs were going to warm me of impending doom, however they did help me with my old 2006 Civic when I had a leaky injector. The high fuel % in the UOA pointed me in that direction.
+1

Even Blackstone has said that they've found no statistical difference in terms of wear between brands.
 
Messages
2,874
Location
pa
if analysis makes you feel better, so be it as its your $$$. like why i use redline in my tt's 4 qt oil pan with 300 hp, to each his own. never any analysis but noticed how the redline raised my vacuum when using the 15-50 in my loose lo mile turbod TT also reduced consumption!! just use typical fake synthetics in everything else!!
 
Messages
13,102
Location
North Carolina
I think a UOA is valuable for evaluating the wear on the oil, not so much the wear on the engine.

I use one from time to time to evaluate fuel dilution, tbn, look for coolant in the oil, and if there possibly dirt getting in the engine some how.
 

BeerCan

$50 Site Donor
Messages
1,717
Location
FL
I think some people use it more for a hobby than anything.
I fall in this category. I do UOA on most of my vehicles on almost every change. The only info I really gained from them is that you can save on the cost by buying a 10 pack from Polaris. Oh and that fuel dilution is a non issue
 
Messages
556
A few years ago a UOA showed there was coolant getting into my oil. I repeated it several times to be sure and it continued showing it. I replaced the head gasket to solve the problem. So, I think that UOA was well worth it. I don't do the UOAs a lot now but I'm going to do in on my 2020 Chevy Equinox to get a base line.
 
Top