I have a '92 Camaro RS with a 305 TBI. In Park or Drive the engine temp. will heat up all the way till @220 until the fan kicks on. But, as soon as you go the car immediately cools down. It only heats up when your sitting there. I replaced the 195 thermostat with a 160, but still no change at idle. any ideas

Sounds perfectly normal to me. There is no fan until the fan turns on (duh); the factory fan switch turns on somewhere around 225° and off at about 205°, give or take about 5 degrees on each point; so yours is doing exactly as it is supposed to do. The thermostat merely allows coolant to flow through the radiator.

Does it overheat? Boil over? Spew coolant anywhere? Misbehave in any way at all? If not, then it's fine.

------------------
"So many Mustangs, so little time..."
ICON Motorsports