Or, do what I have always done:The obvious solution would be to create flow independently of the heater valve position or condition.
Looks like the Esprit undertray has seen better days !The Lotus was getting the fuel tanks refurbished
The Acura was getting a new radiator
The Porsche had a bad oil leak blocking 1/2 of the radiator, I was trying to figure out where it was coming from.
Replacing the fuel pump is much easier and much cheaper than the Porsche! I also had to do that recently on the Porsche.