Join Date: Dec 2008
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Coolant can be VC-7-A OR VC-7-B (B just has a "bittering agent").
The panel gage will show the transmission temperature as fully warmed up at 50 *F. Between 100-220 *F the needle will remain in the same position on the gauge. At 230 *F it will move up slightly to the middle of the normal range. At 250 *F it will move to Yellow. The gage moves to red at 280 *F. This is supported on page 36 of the OBDII Theory and Operations manual. The tow/haul light will flash at 275 *F.
Engine Temperature Control:
Engine temperature is not the only parameter that the PCM monitors to determine cooling fan operation. This is the reason that you will see some variation in engine temperature as it correlates to fan operation. The operation/description of the FSS (Fan Speed Sensor) from the PC/ED manual has a fairly good explanation as to how the system "thinks". This is not your traditional engine hits temp X and the fan clutch locks up. The fan speed sensor is a Hall-Effect sensor integral to the vistronic drive fan (VDF). The powertrain control module (PCM) will monitor the sensor input and control the VDF speed based upon engine coolant temperature (ECT), transmission fluid temperature (TFT) and intake air temperature (IAT) requirements. When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required pulse width modulated (PWM) signal to a fluid port valve within the VDF.
My understanding of fuel pressure:
Fuel pressure is regulated to 100 psig out of the HFCM.
Then a recirculation regulator opens at 60 psig to take the fuel back to the HFCM.
Oil temperature is usually 10-25 *F above coolant temp. Engine begins to defuel at 254 *F oil temp. Oil temperature should NEVER exceed the ECT by more than 25 *F.