im not mechanic, but check the compression. if that cylinder is low on compression then it means that either the valves are bad or the piston rings are.
Have a 2004 Ranger Edge, 3 liter, 128,600 miles. What direction does the coolant flow through the heater control valve.I see the arrow but does it flow into the heater core or control the flow out of the core. Bubba (not me ) replaced the original one with will fit after breaking. That one, now leaking, had the flow arrow showing fluid exiting the core. Wouldn't that pressurize the core. Help. Thx. tomrob1@cox.net