It does. Even with high capacity oil coolers I see the oil temp increase at higher speeds over time, even with the water temp staying normal. Most likely the problem is the increased windage from the rotating parts sitting in the oil. This is why many race engines run dry sumps. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Dave Mcneely
Sent: Saturday, May 22, 2010 7:56 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Optimum WBX rpms; was RE: 4 speed/5 speed shifter

---- Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM> wrote:

> I do not see any reason why 4,200 rpm would produce particularly  higher oil
> temps than 3,800 rpm would.
> other than slightly increased load due to speed and aero drag ...
> I see no reason especially why oil temps would be higher with a bit more
> rpm.
> Scott

Scott, maybe it's the slightly increased load.

David McNeely