Originally Posted by wstar

Re: the Mocal questions, I called them a couple of years ago when I bought my thermo plate, I've posted this like 3 times on different threads here somewhere:

The Mocal starts with both passages (oil cooler + bypass) open. The thermostat closes the bypass passage gradually over roughly the 175-185F range. So at 185+, basically all of your oil flow is forced through the cooler. Under 175, most of it takes the bypass route (least resistance), but a small amount will still flow through the cooler as well since the passageway is open (and this helps warm up the cooler and lines themselves, so it's not a sudden temp shock).