On most older cars the fan is driven by a serpentine belt with a viskosity clutch. Whenever the engine gets hot, the clutch engages. As the engine gets older, the clutch fails and the fan turns constantly, robbing horspower and gasmileage. Here's how to get rid of that problem and replace the old fan with an electrical one.

Parts: Electric fan from a 1995 Camaro 6 Cyl. (40$, wrecking yard).


Hayden fan control unit with A/C wire and adjustable thermostat switch (36$, Autozone).

Process: Removal of the old fan/clutch assembly was easy: simply unbolt the four bolts that attach the water-pump-pulley to the water pump, and the whole fan/clutch assembly comes off. Just don't forget to put the bolts back on before you start the engine or you'll have your water pump pulley flying around (don't ask ).
I couldn't get the shroud out separately, because the fan was in the way, so better unbolt the fan before the shroud. Now there's lots of space between radiator and engine: I've been driving around like this in Houston traffic with temperatures around 15-20° C (~65° F) without major overheating problems. The engine only started to heat up once, when I got stuck in traffic and it was stop-and-go for over 10 minutes. Apparently, those are the only conditions the fan is really needed.Reassuringly, the Camaro-fan is roughly the same size and design as the stock fan, so there shouldn't be any trouble with overheating at all, even in the Houston summer. After trimming the Camaro shroud with a Dremel tool, I've fit the Camaro-fan into the old shroud. I used four locking bolts (with large washers) in each corner of the Camaro-fan to place it slightly offset so it would end up in the center of the radiator. On the floor is the Hayden controller with the wires. I also trimmed the depth of the shroud to gain clearance between engine and fan.

Installation of fan and controller was easy and took about an hour or so. Even with the trimmed shroud a lot less room now than there was without any fan... I mounted the controller on the driver's side, right next to the radiator. Just below the radiator I drilled a hole for the ground wires from the controller and the fan. The temperature sensor was installed to the exit of the radiator, so it would measure the temperature of the water entering the engine. I took the ignition signal from the wiper motor (upper arrow, right image) and the A/C clutch switch spliced right into the positive A/C clutch wire with a splicer that came with the Hayden controller (lower arrow, right image).

One thing's definitely sure after the electric fan install: The truck is MUCH quieter now and overall runs smoother.