Purpose of VOA/UOA

Jan 25, 2003
Decatur AL USA
I'm somewhat baffled by the purpose of some of the VOA/UOA often posted here.

The fact that TBN is still focused on by many is a bit strange considering many major engine manufacturers now have no condemnation limit for TBN. Many oils that pass manufacturers test now finish with less than 1.0 TBN D4739. The modern nonmetallic ashless additives simply don't respond well to the test. They concentrate on Oxidation and Nitration instead.

Here are some omissions that bother me with no indications of problems.

1. TAN (None)
2. Oxidation (None)
3. Nitration (None)
4. Sulfation (None)
(Sulfation is no longer as important with modern fuel).

When people have indications of fuel or soot. (You do a blotter on occasion, correct?)

5. Dedicated Fuel Dilution Test (None)
6. Fuel Soot Membrane Test (None)

Why people constantly try to guess when they are going to the trouble of doing a VOA / UOA I don't understand.
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It would be nice if they could decipher the base oil part to satisfy the POA groupies and the Ester heads. Right now those percentages are usually just a range on the manufacturer’s info sheet. ;)
I would categorize both the UOAs and VOAs that I have conducted as a hobby rather than anything of particular value with respect to engine maintenance. I find it interesting to see how viscosity changes and TBN depletes over the interval but I have never taken action on any of the analyses. Like you stated, TBN will deplete at different rates for different oils and some of the Euro long life oils have a low starting TBN. But without a VOA and subsequent UOA you would not know that interesting fact.

Here in the UK a V/UOA costs in the region of £35 ($45) which is more than the cost of a DIY oil & filter change on any of my vehicles including the R8 so there is no cost / benefit to V/UOA to push the OCI, especially as I usually reach the time limit before the mileage limit.
Terry Dyson fills in the blanks of the UOA's that others like Blackstone miss. Try one of his UOA services, which includes his analysis, more than just a small block in the UOA form.