2006 Toyota Highlander Hybrid PP 0w20 5145 mi

Aug 14, 2015
I just did another UOA with my Highlander, courtesy of the Pennzoil team that furnished the oil & the UOA testing, as well as the tshirt that I now wear when changing my oil.

Wear numbers remain low, although there is probably a coolant leak, as seen in the Potassium.

They flagged the titanium, although I have seen a VOA of PP 0w20 that had 2 ppm titanium, so I'm not sure that is or could be an issue.

I was originally going to take the OCIs to 7K or even longer, but the drain of the RGT was done with the oil level right at the add mark; the drain of the PP was done with oil level about 2 mm below the add mark. As measured on the dipstick, it represents consumption something over 1.5 quarts each OCI.

Here is a link to a prior UOA done with this vehicle: https://bobistheoilguy.com/forums/t...20-3mz-fe-3-3l-6200-miles.316076/post-6154278. Unfortunately I am not 100% sure what oil I used in this earlier UOA (I wasn't thinking of doing a UOA when I did the oil change), but the other two, on the report given below, I am 100% sure about the oil used each time.

One curiosity is that TBN continues to be fairly low. On these last two, it was in the 2.x range; in the one I linked to above, it was 1.5. All three OCIs ranged from 5100 to 6000 miles.

FWIW, I had the radiator replaced at 137K in 2020; the timing belt was done in Oct 2022 at 154K, along with the crank shaft seal that was leaking. The OCI was from 151K to 156K. Folks here who know this engine can probably comment on the chances of small amount of coolant entering the oil because of the crank shaft seal.

So what do you think--specifically, about the potassium levels? Given that wear metals are as low as they have been with the two previous UOAs I did, I'm not greatly concerned, but of course I do want to eliminate this ASAP.

PP 0w20 Feb 2023 UOA EditedSMALL.png
Last edited:
I wouldn't be concerned at all with the titanium. Often times, there will be trace amounts of wear metals and sodium in new oil samples.

I would continue to monitor coolant levels, if your potassium level increases on the next OCI, then I would start in on leakdown testing.
FWIW, I just got off the phone with a Pennzoil technician who identified as a "formulator" of both oils in the UOA (RGT & PP)--part of the Pennzoil UOA program I was invited to join, and he said that he the potassium level isn't enough to warrant concern, or another UOA for that reason. He also recommended for older my vehicle, with 156K, to go back up to 30 grade oil, as I explained that I lost a quart and a half of oil during this 5200 mi OCI.