Temp gauge mod KZN165R

[Geoff Cobden]

I have just successfully modified the factory temperature gauge on my KZN165R. 

As some of you may know factory temperature gauge in hiluxes are set up in the factory to show about a third from 70deg to 110deg.  I didn't find this acceptable.  This has been done to show you what they want you to see, not what the real temps are.  This makes it about as useful as a temp light. Damage is done before it tells you anything. 

I did not want to install an after market gauge so I searched for how to take the dead zone out of the factory temp gauge.

I found two sites that explain how to do it but they were for a series 2 Hilux/Surf and the other for a Landcruiser.

The instructions in both of these sites are accurate in how to do it but not what size resisters are required in KZN165R Hilux.

Search temp gauge mod in google and find the Toyota Surf site.  I found that if you follow the instructions found but use the factory 75ohm resister that you remove instead of the 56ohm specified and a 100ohm resistor you will get a good result. Mine sit just below half at 82deg,  which is the thermostat temp and hits the red at 100deg C, completely linear.

The Landcruiser site is also good as it has a good explanation of what the resistors do.  The 100ohm resistor sets the centre position of the gauge and the 75ohm changes the range.

With this mod anywhere in the white zone is safe. You will be surprised to see what the temperature is actually doing.  Mine sits at 82deg around town at 60kph.  At highway speeds it varies between 85deg and 92deg (hill climb) If I hold it flat it takes about 10km reach the highest I have can achieve of 95deg which is about 3mm below the top white line.  95deg is the temp that the thermostat is fully open.  If I continue this linear rise the red would be 100deg.  This was all verified with access to the ECU via an OBD reader.

I am very happy with the result as the KZN165Rs are known to crack heads if they get too hot and the factory gauge does not tell you what he temp is actually doing. 

I found the mod very simple as it just requires desoldering a resistor and diode and soldering in 2 resistors.

I trust you find this information helpful,  regards Geoff

 

Edited November 22, 2016 by Geoff Cobden