my engine temps are excellent, no overheating, and no cooling system issues. IR gun readings are fine, and gauge is not
out of the proper range. cooling fans operate properly.

ECTS reading with the bosch hammer shows 206' at speed, and 212' at idle. not concerned about proper engine temps, but
wonder if the hammer is seeing these temps, does that mean the control units (LH/EZK) are seeing these readings and altering
functions based on those temps?? or is the hammer faulty? am I missing something?

 

Just did a Hammer reading yesterday on one of my members '90 GT. Funny 206° F was the reading I got at idle.

 

too funny!! that can't be measuring actual coolant temp? were there any issues with your friends car?

 

No over heating issues.

 

is the hammer NCTS temp reading taken from a different source or have a different meaning? I am certain, at idle,
my coolant temp IS NOT 212'

 

I understand the hammer will be reading the temperature input that guides the LH/EZ modules and this is the temperature of the coolant as it leaves the block. This temperature typically sits about 6 degrees C or so higher than the temperature of the coolant as it returns back to the engine.

The first cooling step is controlled by the thermostat and that is self controlled by the temperature of the coolant in the block. This item opens at 83C and as I am aware is fully opened by the time the coolant in the block reaches 90C [there or thereabouts]. The fan programme then modulates the fan system based on the coolant return temperature it measures such that between 79C and 85C I understand it runs one fan and changes the applied voltage from 7.5 volts to 9.5 volts in a linear relationship. At 85C the applied voltage drops to 8.5 volts but is now applied to both fans and this voltage increases as the coolant outlet temperature increases such that the fans see 12 volts at 95C. Certain conditions and combination thereof will override the basic temperature control programme.

The cooling slats [if your model has them] open to 30% at 79C and then go fully open at 85C again driven by the temperature of the coolant as it is returned to the motor.

Thus if you add say 6 degrees to these numbers the temperature profile as seen by the LH/EZ modules will be 83C when the thermostat starts to open, 85C when the slats open to 30%, 91C when both slats are fully open and 101C if both fans are running at max voltage. If the a/c is running I understand the system simply runs both fans at 12 volts but not 100% sure on that one.

Thus at the moment when the ambient temperature is around 40C over here my system runs with the temperature gauge just to the left of the last white line which suggests a temperature leaving the engine of about 98C [208F].. If I run with ST2 connected I can read the temperature as seen by both LH and EZ units and if my memory is sound, that typically indicates about 97 degrees C [206F]. Thus why I infer that the last white line represents 100C [212F]. Some dash gauges will read differently but I put that down to dash panel gauge calibration and not an accurate measure of the engine temperature. I have owned two 928's- my late 90S4 and the current GTS chassis with the same engine unit in both and the gauge display shows identical characteristics. I view the panel gauge as a reliable benchmark that will indicate when something is not right.

If I run the car in the winter time with the a/c off the needle on the dash panel moves a bit lower -i.e. closer to the mid white line on the gauge but to date I have not taken a temperature reading with ST2 in such circumstances.. If the car is running at speed the air blast takes care of things. At low speed in traffic the a/c struggles a bit but the dash panel temperature indication more or less stays constant suggesting that the fan programme works rather well.