We were discussing this deep in another thread, but I thought I would pose my question succinctly on its own for more insight. Really more a question of theory than of a suspected problem with my car...

Simply stated, should the radiator be able to exchange more heat than the engine produces when there is no moving air (when idling in traffic)?

Mine does not. My temps are held in check by the cycling of the fans - no problem. My assumption is that this is normal and expected.

Others claim their cars can maintain an equilibrium temperature below that at which the fans come on. Is that possible at moderate ambient temps? Is it typical?

 

I'd say that depends on the ambient temp, how efficient your radiator is, what other cooling mods you've done, and what temp your fans are set at (PFC).

it took longer sitting at idle to trigger the fans when i got my fluidyne and new motor with ported coolant and iol passages. Even longer still when I upgraded my oil coolers... and now that i've set my fan trigger temps lower, they come on sooner again!

 

what i measured when i changed coolant and radiators was i let the car warm up at idle to 100c hit the fans on high and timed the drop to 90c. replaced the rad and coolant. added some water wetter and the time was faster for it to drop.

 

I have a Koyo radiator, stock thermostat, 95C Miata thermoswitch. No other fan mods. Currently running 70% coolant/water.

On a theoretical 60F day, should I expect my car to maintain temperature equilibrium at idle/in traffic below the temperature where the fans kick on (95C)? Does yours?

I read these posts with folks claiming to never see over 85C in stop and go traffic and I'm trying to ascertain whether that is really attainable or if their fans are set to run non-stop or if it is simply exaggeration.

 

It's been cool recently here in Pensacola, and I typically see the temps sitting around 80-90 deg. C. I could see that working if you lived in a cooler climate, but whenever it warms up here a bit temps do creep up pretty easily when sitting at a light.

The radiator really needs airflow over it to work well, and at a dead stop it will slowly heat soak. I don't think there's any way around that - you gotta have the fans goin'.

Dale

 

hell just think about how hot you get in the cabin at a light. and how fast you feel cooler when you get going. same thing goes on under the hood