Join Date: Nov 2009
Location: Redford, MI
Bronco Info: '96 Black 302 XLT - '94 Green 351 E. B. both are E4OD, 3.55 axles, 31 10.50x15
For the heat issue: Try reverse flushing the heater core, if that doesn't work, the heater core might be plugged. (This is assuming that the coolant is full.)
The temperature gauge is an analog device, it changes resistance as the temperature of the coolant changes. So it is NOT like the oil pressure sender, which is just a switch that closes at about 5-7 pounds of oil pressure.
For the valve covers: Look at the valve stem seals, the oil drain back holes, spin the pushrods to see if any are bent (if the engine has been running fine, you probably don't have any bent pushrods). Check/replace the PCV valve grommet, the PCV valve should be a fairly tight fit to prevent leakage. I'm sure there's more that others will add.
"The simplest solution is usually the best solution" - Occam's Razor
"The significant problems we face cannot be solved at the same level of thinking we were at when we created them." - Albert Einstein