When "should" the AC Radiator fan turn on?

[Delocalypse]

I've had some time to poke around a little exploring why my engine temp is running warmer
on hills than it did 22 months ago when I got my Deli. Back then I replaced the cooling system , rad/pump/belts/fluids/filters, the
whole thing. Drove San Diego and back in the Summer with no problems. Temp never went over 3/4 even on the longest I5 Freeway climbs.
Max 3000 rpms, Heater on full and head out the window

Had some work done 12 months ago to replace a crankshaft due to worn bearings. The crankshaft was starting to loosen and slightly tapping the flywheel inspection plate cause an increasing metallic rattle. Not sure if it's in my mind but now the same hills I once drove , Vancouver - Whistler cause the temps to spike faster and make me keep one eye on the gauge all the time. I've ordered a Pyro guage w/alarm to wire up , so that should give me some anxiety relief but checking in here to see if there are other suggestions.

I was curious when the AC Radiator fan is supposed to kick in? I never use the Air Con but am thinking with that system blocking the front of the Rad how is that helping cool the engine? If the little electric Air Con fan were on it should help draw more air in and cool things faster but it never seems to kick in.
I marked the blade to see if moves when I ran thru a bunch of options but so far no movement: Ie: Heat controls onand off / Ran Air con at hot and cold / idled for 30 mins, ect... The engine temp never ran hotter that 1/2 on the dash gauge. Does the temp need to be higher than 1/2 or does the airt temp need to a certain temp before the Air Con Rad fan kicks in?
Maybe remove the Air Con Rad and let more air cool the engine? Get the Air Con Rad Fan working and use it to help pull air into the Rad?
Thoughts?

Thanks.

[nxski]

A quick note, your temp gauge shouldn't get up to 3/4 at any time. If its above 1/2 pull over and let it cool down. When being driven appropriately your needle should read a constant 1/4.

[Delocalypse]

The temp has never hovered below 1/2. Only on a long downhill has it ever sat at 1/4 until the road levels out then it has always returned to 1/2.
Driving Ubc to Boundary along 12th the temp has always been 1/2. When the Deli warms up it just sits at 1/2 on the temp gauge.

Driving up Taylor way then the merge onto Highway 99 I keep the rpms below 3000 which tops the speed out around 60km/hr until the road flattens out and you have to merge left from the third lane . The temp there runs at 1/2 on the climb up Taylor way then above 1/2 rising to 3/4 on the merge onto the Highway. I run the heat once when the temp rises above 1/2 and once the road flattens out the needle settles back at 1/2 and the heat goes off.

24 months ago it never sat at 1/4 when warm, always 1/2. I've never really thought that was bad as ever previous vehicle engine temp also sat at 1/2.

I guess once I install a pyro I'll have a better idea? Maybe..

Thanks

[thedjjack]

Factory gauge between vehicles are questionable...

I do not put a lot of trust in the factory gauge or sender...

I would be inclined to put a mechanical gauge in. Also what temp thermostat is in there, how old is the fluid, is the rad dirty? lots of factors...

my drive up from San D the temp was under 1/2 the whole way but 5 speed revs higher and does not dump trans temperature into the radiator.

[Delocalypse]

Yes true. A few factors. The Rad/Pump/Fluids are less than 24 months old with 20,000k I've put on her. 180,000k total.

If there are any replacement thermo models that are recommended I would be interested in exploring the idea of trying out a new one.
It would either show the same results or lower. Combine that with the Pyro and I might be able to drive up hills without a finger on the heater switch.

Anyone have thoughts on the Air Con Rad Fan operation and or removal for increased air flow to the main Rad?

Cheers.