'09 Forester, Synpower SM, 46K car, 5K oil

[fdcg27]

I took this sample after a warm weather run of Synpower SM 10W-30. Car was short tripped once most weekdays, but was then typically driven far enough after that for the oil to reach operating temperature.
TBN took a real hit on such a short run in mild to hot weather, April through September.
Wear looks pretty good, but not great.
This oil would not be suited to longer drains in this engine as it was used IMHO.
Polaris flagged base number as being below acceptable minimums, while Blackstone would have probably written that the oil could have been run longer.

Iron 8
Aluminum 3
Copper 3
Silicon 10
Sodium 285
Potassium 1
Moly 3
Magnesium 8
Calcium 1084
Phos 623
Zinc 661

Visc @ 100C 10.1
TBN 2.15
Oxidation 13
Nitration 11

Fuel and moisture were at nil levels, while every other value not cited was zero, including lead.
Does anyone know whether these engines use lead free main bearings?

Sodium is an additive in this oil, while a VOA of Synpower 5W-30 showed 1 ppm of Potassium, so I don't think that I have a coolant leak, as a respected fellow member suggested.

 

[volk06]

That calcium number is wayy too low...

 

[skyship]

The figures look good in terms of engine wear, BUT I would look for another brand of oil as the TBN should not have dropped to 2 in only 5K miles. The Calcium and Zinc figures also indicate the additives package is rather lacking.

 

[fdcg27]

Originally Posted By: volk06
That calcium number is wayy too low...


Maybe not.
See this VOA of Synpower 5W-30:
http://www.bobistheoilguy.com/forums/ubb...amp;Search=true

Virgin calcium was only 1412 ppm in this case.

 

[buster]

The newer SN oils are using less metallic adds so on paper they won't look as impressive. This mainly applies to the new SN stuff.

SN Synpower is a very good oil.

Sodium, wt% 0.049
Calcium, wt% 0.211

 

[fdcg27]

Still, TBN doesn't look all that encouraging after only 5K in an engine that is usually regarded as being pretty easy on oil.
OTOH, Some members have written that Valvolne oils will hold a fairly low TBN number for a number of additional miles, since TBN retention is not linear.
I wonder, although I'm not brave enough to find out by experimenting with a fairly young engine.

 

[bluesubie]

I'm pretty sure the bearings use lead based. The TBN probably wouldn't have dropped very much in another 1k miles. Just a gut feeling.

-Dennis

 

[fdcg27]

The UOA showed zero lead, so I wondered.
WRT to TBN, I think you're right, although I don't intend to find out.