Moderator: volvite
The FSM says the ECM is only looking at engine temp and refrigerant pressure, but a hot tranny will indirectly drive up the engine temp by way of the heat exchanger, which is in the outlet tank of the radiator just before the coolant reenters the block. Keep in mind that going from driving to stopped will always cause the coolant to "cook" for a few moments because the water pump is running slower and airflow is reduced, but the coolant in the block still has a large thermal load from producing power. Until all of it circulates through the radiator, the temp in the block will momentarily spike. That's all perfectly normal, but it will often cause the ECM to ramp up the fan(s).TooMuchControl wrote: ↑Thu Jun 30, 2022 2:42 pmI had my cooling fan running even after getting off the road on non-aggressive driving.
I'm wondering if you notice that your temperature might peak for a few seconds - and then go back to normal?
This happened to me, and I only saw it when stopped a drive-thru for coffee. It spikes for a couple of seconds, but the fan kicks on and runs for what seems a minimum amount of time.
I think something might be boosting the keep the transmission cool, not just the engine.
check your transmission oil, if this is an automatic. Makes sure it's in good shape at a good level.
check your coolant tank for anything that doesn't look normal.
After I changed the tx oil, never happened again.
I think the Tx oil temperature sensor will trigger the fan to come on, even when engine coolant temperature is normal or within range.
Coolant and tx oil are really good. I notice it comes on as soon as there is stop and go traffic. Highway is fine for the most part (I think). Not sure what the tx temp is, but I haven't seen coolant temp go over 206, so it's not overheating. Runs great.TooMuchControl wrote: ↑Thu Jun 30, 2022 2:42 pmI had my cooling fan running even after getting off the road on non-aggressive driving.
I'm wondering if you notice that your temperature might peak for a few seconds - and then go back to normal?
This happened to me, and I only saw it when stopped a drive-thru for coffee. It spikes for a couple of seconds, but the fan kicks on and runs for what seems a minimum amount of time.
I think something might be boosting the keep the transmission cool, not just the engine.
check your transmission oil, if this is an automatic. Makes sure it's in good shape at a good level.
check your coolant tank for anything that doesn't look normal.
After I changed the tx oil, never happened again.
I think the Tx oil temperature sensor will trigger the fan to come on, even when engine coolant temperature is normal or within range.
205F is right where the ECM kicks the electric fan to high speed, so it sounds like you're running borderline hot in traffic. That might very well mean a weak clutch on the belt-driven fan. We didn't get any applicable vehicles through the shop the last two days, so I wasn't able to check one for you.
That's a stuck valve in the clutch or all fluid has leaked out. Any viscous fan clutch should give you more resistance hot than cold. The way they work is with a bimetal element (yes, just like an old choke spring) that gradually opens a valve as it heats up, allowing flow through a viscous coupling that creates shear between a pair of plates and results in more resistance. This is a great vid explaining how they work: