I normally would not start a new "coolant temp" thread, but I'm stumped and need some direction.

History:
I recently replaced head gaskets, BP Utah radiator, BP Utah water pump (brass impeller), but kept my ~year old Grey LR warm weather stat.

Issues:
My idle temps spike to 203 and drop to 201 - 202. I feel they should be around ~197 max (that's what I remember seeing on Ultragauge pre-head gasket replacement).
Cruising around town its fine, I'm at 190-194. Highway speed reads 188.6 - 190, consistently.

What do you think is causing these higher 'unstable' idle temps? I'm certain all the air is out of the system. Three days of obsessing over 'air in the system'. I'm fairly certain its bled out.

 

Numbers look like air flow.. Fan clutch working fine?

If you raise rpms at idle does it drop quickly from the heightened flow? You could have busted some junk loose.

Are all the pulleys in good shape? Drag from a going out bearing could do it too

 

Mine was getting warm at idle until I replaced the fan clutch. Now it can st there all day at desert temperatures and the temp gauge is rock steady.

 

^^ Heisenberg ^^

 

If I slightly raise the idle, the temps instantly drop.

Pulleys spin freely, I cleaned and re-packed during reassembly.

Fan clutch is what I was leaning towards. But I did the spin test at operating temp, the fan spun maybe a 1/4 to 3/8 of a turn. I thought that was normal, no?

 

I had an interesting "discovery" today. If I get the A/C condenser fan to run my temps drop to 194.0. So, I'm thinking it's an air flow problem, like Dusty pointed out, but it seems the viscous fan is cranking some pretty darn good air without the help of the condenser fan. Hmm?

Should I just order a new clutch and be done with it?

 

I would be prepared to bet that the clutch is weak and although the fan is turning, it's not turning fast enough.