I need some advice…
Today I took my 2006 6.0 F350 for a mountain drive on some narrow, winding roads. The incline was steep, but the weather was cool, around 50°F. My EOT peaked at 215°F and ECT at 210°F but would drop to EOT 185°F and ECT 178°F, depending on the load. Does this sound normal to you?
Also, my FICM voltage stayed between 47.5V and 49.0V, never outside that range. Should I be concerned about the 47.5V reading?
Those temps and FICM readings are normal. Nothing to worry about.
Time to throw on head studs and delete it… just kidding!
Your peak ECT and EOT temps are fine, but dropping that low seems unusual. It might be a stuck-open thermostat. It’s not harmful, but your truck should ideally run closer to 188-192°F on the low end.
Sam said:
Your peak ECT and EOT temps are fine, but dropping that low seems unusual. It might be a stuck-open thermostat. It’s not harmful, but your truck should ideally run closer to 188-192°F on the low end.
When coasting downhill, a diesel engine produces very little heat. I don’t think there’s a problem here.
@Wei
That’s what the thermostat is supposed to manage—keeping the temps above a certain range. If it’s not closing properly, your temps can drop below the designed range of 188-192°F.
Sam said:
@Wei
That’s what the thermostat is supposed to manage—keeping the temps above a certain range. If it’s not closing properly, your temps can drop below the designed range of 188-192°F.
The thermostat only prevents coolant from circulating through the radiator. It doesn’t generate heat. If it’s fully closed and the engine is under no load, the heater core might act as a mini radiator, especially if your HVAC is set to heat.
@Wei
I know the thermostat doesn’t create heat. It just keeps the heat produced by the engine from escaping through the radiator. Unless it’s a long downhill run with no load, it should still maintain at least 188°F.
@Sam
Yeah, on a long downhill grade, the engine heat can drop even with the thermostat fully closed. I’ve noticed the same thing on my vehicles.