hey guys what year did they start the failsafe cooling in 150s? i have a 97 4.6 and was just curious. thanx in advance.

 

They started it with the 97 redesign.

 

ok cool looks like i just made the cut then lol

 

I'm not familiar with '97-up trucks, but FSC should coincide with electric fans. That's its main purpose.

 

Failsafe cooling is a feature of the triton line of engines.

 

Steve83, Failsafe cooling is a feature that came out with the 97 Triton engines. It is controlled by the CHT [ cylinder head temperature sensor] and when the sensor indicates a overheating problem the PCM takes over and starts shutting down injectors. This makes the cylinder or cylinders become a cooling pump for the engine and still lets you drive the truck without damaging the engine.

 

I'm aware of how it works, and why. I had to do a lot of research when I converted my tan CV from EEC-IV to OBD-II. I've even witnessed it in action, after a slow heater core leak drained the system during an 8-hour trip.

The reason you need something failsafe is because the fan is more likely to fail when it's only powered by an electric motor. At least with a clutch fan on the WP, it'll keep spinning & doing SOME cooling - but if the electric motor dies or locks up, there needs to be a backup system. That's where FSC comes in - you can keep driving almost indefinitely with no fan, or no coolant (not that I recommend either) because the temp sensor no longer relies on coolant to give an accurate reading, and the engine can "limp" to cool itself off (within limits).

Even on trucks with belt-driven clutch fans, it doesn't hurt to have that programming in the EEC, and standardizing the EECs makes them cheaper to produce.