Paul94Z28

What temps do the fans come on for the 3.8 V6? The t-stat opens at 195 as expected, but the car goes up to 210 and no fans yet...

Injuneer

Probably the same as the V8... low speed at 226*F, high speed at 235*F.

[EDIT] Verified above in the 2000 factory service manual.

Paul94Z28

wow - that seems hot. Have not been up that high given the temps outside are in the low 30s...

Will pay attention when it warms up a bit.

Injuneer

GM designed the engine to run at ~210*F. Best combo of low emissions and good fuel economy. That's why the middle of the gauge is where it is. A 195*F t'stat only starts to open at that temp. Doesn't fully open until about 210-215*F.

peterpar

Here's a copy and paste from the 1994 Service Manual for a 3.4L cooling fans:

OPERATION
The engine coolant fan is controlled by the PCM
via the coolant fan relay. A calibrated set of criteria
programmed into the PCM will energize the fan relay.
The following conditions control the fan:
• Engine Coolant Temperature (ECT) sensor
signal indicating 109°C (228°F) or greater will
turn the coolant fan "ON."
• Engine Coolant Temperature (ECT) sensor
signal indicating 98°C or less will turn the fan
"OFF."
• The fan will turn "ON" if A/C is requested and
vehicle speed is less than 56 km/h (35 mph).
• If vehicle speed is greater than 113 km/h (70
mph) the fan is disabled and will not turn
"ON."
• If A/C is requested and refrigerant. pressure
sensor indicates approximately 20 psi or
greater the fan is turned "ON."
• When the PCM is operating in backup the fan
will be "ON."
• When any A/C DTC is set the fan will be "ON."

Injuneer

His question is about his 2000 3.8 V6 with dual fans.

peterpar

Excuse me Fred, I read it too fast and stop looking at the signature after seeing 1994 Camaro.

GaryDoug

By the way Fred, Pete is the guy who did the excellent work on the service manual bookmarks. I haven't posted that here.

Paul94Z28

Appreciate the support guys - Thanks!