Sorry guys, I'm at a loss... it sounds like the systems are working on both of your cars, at least mechanically. The only other thing I can think of would be to flush the system? I know Chuck had an issue with his getting gunked up but we were never able to figure out why... he got the wiring straightened out, they flushed the system and his worked perfectly until he sold it to by the SA-20. I lost track of the car after that.
I had mine apart a year or so ago and flushed the entire system. I also removed the radiator from under the front, straightened out all the bent fins, repainted it and flushed it with a hose.
Wish I could help more, but I just don't have any ideas at this point...