What is the difference between the two functionally? On a 2004 Discovery 2, the CTS is on top of the engine by the alternator, the RTS is by the lower hose on the radiator. Thanks to all.

 

The top is after the thermostat.
The bottom is after the radiator has cooled the coolant...and the gauge is notorious for being inaccurate.

 

Got it--many thanks.

Does the ECU use the resultant temperature differential to make decisions does anyone know -- the delta of hot to cold coolant -- or is setup pretty stupid and the CTS is goto for most everything which would explain a) why I never knew the RTS existed until I replaced the radiator b) scant mention of RTS in forum (vs *much* info re CTS)... equivalently, is RTS for some trivial scantool monitoring stat that isn't relevant to the real-world biz of running these beasts? Endless thanks -- couldn't run my rover without y'all. happy new year.

 

The RTS is specifically for use by the Secondary Air Injection system to determine when to activate that.

 

thx so much!... was buggin' me
Enjoy