This is a really old thread, but I'm wondering about
oil temp as well and it seemed better to reply to this than create a new thread. I have Smiths gauges, and my
oil temp usually reads 40C. The highest I've seen is 60C, even when the
oil cooler is taped. The water temp behaves normally, quickly coming up to 80-90C, where the fan does a good job maintaining water temp. I'm running 15W40, so oil pressure is about 65psi when cold. Once the oil temp comes up to 40C, the oil pressure behaves normally, i.e. comes up to ~60psi at 3k RPM, dropping down to 25 psi at idle so it seems like 40C is adequate for good lubrication. I'm just a bit concerned with not getting the oil hot enough to drive off water, etc.
I'm wondering whether the oil temp capillary is losing enough heat to affect the reading. It seems unlikely that there would be a 30C difference between oil and water temperature at steady state?