jsm02cpa wrote:If the coolant hasn't been changed, you may want to do it now and flush everything out good. Run clean water through it, keep doing it until you don't get any hit of rust or murky water coming out. Then refill with 50/50 mix of antifreeze and water.
Agree, except that part about the fluid mix. Put in what the mfg says to put in. Not all coolant is created equal and some coolant won't mix well with other types.
Do the flush and fill first. If that doesn't cure your heat problem, then you may need more expensive repairs.