Continue to deal with air lock!

I haven't posted for a long time and my conversion is still functioning but I have two problems. I am getting air trapped in my coolant line and can't seem to figure out where it is coming from. I tried swapping out a few fittings and installed a bleeder valve to free the system of trapped air. It works for a while then the air comes back. What this means for me is that my car will not switch over as fast as I would like, 5-7 miles of driving rather than 1-2 miles. I think I found a solution on the Plantdrive web site and that was to purchase a 12 volt coolant circulator that will circulate the coolant and get the car to heat up faster. I can plug my car in at night and the circulator will keep the system hot at night, and push any trapped air out to the coolant overflow. When I get it I will post some pictures. Another problem is Marty and I discovered is that the valves we use (Hydroforce three way) allow small amounts of fuel to cross contaminate. Thus I get small amounts of diesel in my svo tank and worse small amounts of svo in my diesel tank. This isn't a problem in California, but is the Northeast it is hugh. I began to have problems with starting and pulled some diesel out of my diesel tank and discovered the svo in my tank. The solution was to get from Craig at Plantdrive three check valves that are one way and keep this from happening. I wouldn't install a system without the check valves, especially if you live in a cold climate. I have over 60,000 miles driving my cars on svo. Chris