Thread: Thermo's and switches

I would have a switch triggered by the temp of the heads or manifold rather than the radiator, although lots of cars have them in the radiator,

I posted a thread called something like "cheap temperature gauge" for $25 which has a relay control for fan switching.
I have one in mine and it has been great though I do not have it switching a relay.

My RRC 3.9 with viscous fan runs at about 92-94C on a 30C plus day so I would switch at say 96 in say 92 out, if you do not want them cutting in ands out all the time .

I have never had my a/c fans come on for temp, although heat soak after switch off adds about 5C and I have seen 100C on a hot day by my gauge, but I do know what that is at the thermostat
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I would keep the A/C fans but you should be aware that they draw about 8amps each and the bigger fans will be 12amps each plus. during hot slow work or at idle it won't take long to drop the battery, as most alternators only put out about 15amps or so at idle.
Regards Philip A

yeah, mine behaves much the same. Normal is just below 90, push it hard up a big hill and it mite get to around 93-94. I do notice that the guage reads low (80deg) in easy driving at low, 10-15deg, temps and down to near 60 in sub zero ambiants. Guage is in top radiator hose which i know is not ideal.

I'm guessing the sensor location may play a part in the switching temp range required, ie a lower setting if fitted to the radiator tank than if fitted to the t/stat housing. Maybe i should run the heat gun over the tanks and see what it reads compared to the guage.

So maybe a 95-90 (available in M22x1.5 thread) to switch the main fans and the std 102-97 for the condensor fans. Could maybe even switch the main fans in 2 stages.

I do have dual batteries and dual alternators, so not overly worried about the amp draw, but its something to keep in mind.

You may find your original condenser fans a hindrance to actual airflow. So maybe better to remove them. I'm using EL Falcon fans on mine and still have AC but also a trans cooler with its own fan. Although this covers approx 1/3 of the frontal area the EL fans draw results in the trans cooler fan spinning at considerable speed even when stationary. It maybe that the original condenser fans will be too much drag?

Originally Posted by FIXR7

You may find your original condenser fans a hindrance to actual airflow. So maybe better to remove them. I'm using EL Falcon fans on mine and still have AC but also a trans cooler with its own fan. Although this covers approx 1/3 of the frontal area the EL fans draw results in the trans cooler fan spinning at considerable speed even when stationary. It maybe that the original condenser fans will be too much drag?

Good point.

The fans that i have are Ford, guessing falcon but no idea of model. The shrouding looks differant to the cut and shut AU fan i fitted to my Suzuki Sierra tho.