From time to time, my oil pressure will drop to zero and then after a bit come up again. I thought it was happening at a constant speed but maybe not.
I have an oil pressure gauge and I can watch it drop down and when it gets to zero the light comes on.
I have an external filter and external cooler and a CB Thinline sump.
I checked the oil level when this happened and it was a bit over the add oil level. I have read that this is a good level when using the add-on sump. One other reason I didn't fill it to the full line is that I have been having oil come out behind the crank pulley, even after I added a sand seal.
I have a Mocal thermostatic sandwich plate between the filter and the mount to control flow to the cooler. Oil enters the cooler at the bottom and leaves the cooler at the top. I put the outlet at the top to prevent air from getting trapped in the cooler. The cooler is higher than the sump.
Does the Mocal stop oil from draining out of the cooler?
If not, the oil level I am reading may include oil that has drained out of the cooler and after filling the cooler my oil level may be too low.