I have a 1998 XLT. Last week I got the infamous plenum replaced in my air conditioning unit (the thing that allows you to change temperatures). The following day, I drove her about 15 miles to find that there was steam coming out the front grill = overheating radiator. Driving home, I just crossed my fingers that I could get home and glued my eyes to the gauge, and sure enough, nothing happened. Nothing happened when I drove it the next day either. Yesterday however, as soon as I put her in drive, a low pitch whistling started, and as I sped up, the pitch of the whistle got higher. This morning I started her up and drove a few miles and NOTHING! A friend of mine said the whistling could be related to the water pump for the radiator in some way. Has anybody had this sort of trouble before? Could it be in any way related to the ford dealership fixing my a/c and screwing something up? Just seems odd I never had this trouble 'till the day after they had it. Thanks in advance everyone, Dustin

I just wanted to know if you are really overheating? Does the gauge go up real high or are you just leaking? #1 cause of radiator leaking/blowouts isn't overheating, but rather bad radiator caps. (so I'm told) then usually comes the overheating. The whistling you hear probably is the water pump locking up and the belt squealing on the slowed/ stuck pump pulley. Replace the cap, flush the system, refill with water (so when you replace the radiator you won't have to pour out expensive antifreeze) run with the AC on and let it idle and see if it gets hot.   The rule is, if it gets hot while idling it is the pump or cooling fan. If it get hot while running regular, it is the thermostat.   I had to run the thermostat yesterday. I soon realized the SOHC explorer is much different then the normal explorer. Different wires, and a double spring thermostat. (safety thermostat)   Chris Robertson