M1 0W-40 SN, TBN/TAN, 5130 M, 85 Corolla 4A-LC

[Gokhan]

This UOA was originally posted in this thread:

Thin or thick (TGMO 0W-20/M1 0W-40): Final verdict

Sampling interval is 5,130 miles and 546 days.

It's the original, non-FS version of Mobil 1 (M1) 0W-40 SN/ACEA A3/B4/MB 229.5 with Toyota 90915-YZZF2 oil filter. Oil loss in 5,130 miles was only about 0.3 - 0.4 qt, almost the same as or perhaps slightly worse than TGMO 0W-20 SN in the previous OCIs. No makeup oil was added. Almost no oil consumption is thanks to replacing my valve-stem oil seals. There is a small oil leak at the oil pan. Oil-change capacity is 3.5 quarts with oil-filter change. Dry-fill capacity is 3.9 quarts. Cumulative miles and age on the 1.6-liter carbureted SOHC engine at the time of the UOA sample was 266,190 miles, ~ 32 years. In addition to some high-speed freeway driving, the car mostly saw a lot of short trips that you would think would be hard on the oil. Temperatures in the area were mild, warm, or hot. Also, the sampling interval was about a year and a half, past the one-year-maximum recommendation.

I used the high-quality aluminum Blackstone vacuum pump for oil sampling.

I also used ACDelco cooling-system seal tabs (part no. 10-108) before this OCI, which seems to have stopped the coolant seep into the oil, as sodium is low this time and there is no oil thickening.

The current fill is Toyota (TGMO) 0W-20 SN/GF-5 made in US by ExxonMobil again but with Mobil 1 M1-103 oil filter this time.

Comments are welcome.

 

[Kuato]

Head gasket time?

Wish I had bought a new Toyota in '85....

 

[bigt61]

Very nice - I'll bet the average wear #'s might have come down if you ran the M1 0W-40 longer. With a TBN of over 7, it obviously had lots of life left. Even the current fill of TGMO is likely safe to at least 7500. Those GM coolant tabs work wonders, but some people just love the fun of replacing LIMGs and water pumps.