Originally Posted by island808
Since then, it likes to see 5 bars occasionally, where as it never used to, even in slow off roading for hours. Maybe the thermostat gets "broken in" or just broken.
As far as synthetic oil transferring heat more readily, I can't find a thing on that. Well, other than other than people in forums.
If your oil temp now routinely reads a bit higher, your oil might have increased in vis, changing the flow rate through the cooling circuit.
As for synthetics cooling better, I have no information that this is so. However, synthetics do tolerate much higher temperatures without cook-off. The Noack scores indicate that. Also, synthetics maintain vis over a wider temperature range...all good reasons to use synthetic in our boxers.