does anyone know how fast is the main cooling fan supposed to spin?(in order to assist in cooling of engine.mine seems to spin fairly slow.does anyone know how this system works(viscus clutch=dont' know if i spelled that correctly.anyways i have to date replaced everything(t-belt/h20 pump/tstat/radiator/serp belt/tensioners/idler roller/temp sensor on backside of engine/g-12/i have bled the cooling system 3 times and w/rear of car up in air.even gauge cluster,i am stumped,i will note that previous owner ran regular antifreeze,heater core is bypassed/although i've tried to no avail w/heater core hooked up but w/ small leak.i will also mention that at normal driving and down here in palm springs its been 100-110 degrees the temp gauge will go to a little past the first big mark after straight up and down.in the evening or on the freeway especially when its cooler like 90 the gauge at like 45-50 will go down to normal temp straight up and then creep back to the next big mark on gauge.this sounds like to me a cooling fan issue,only after i replaced everything else.also when i turn of the car i here a weird hiss sound for about ten seconds,it sounds like its coming from one of the ac lines,although my ac works fine and the small ac fan comes on fine.can anyone think of anything?