I'm going to post this here, because of the title, and the prior posts.
Prior to installing the Flex-a-lite 40 on my 89 Ranger, I went over virtually all the posts here and another site. From that I had the following concerns:
1. Reliability.
2. Adequate airflow.
What I was seeking was:
1. Not having to replace the existing fan which is cracking.
2. Increased power (and gas mileage).
Since I only installed this product yesterday, I can only answer on one of the topics definitively. There is clearly more power. I have a hill I go up everyday that has a 40 mph speed limit and sometimes cops. To go up it in fourth gear with the stock fan I needed to be going about 47 mph and have the accelerator pedal to the floor. With this fan I can easily go 43 without having the pedal pressed all the way. I haven't tried 40 yet. But there's clearly a difference in power, as you would expect. Contrary to popular belief, the clutch does not cause the fan to stop spinning entirely, and the power to move the fan is not free.
As to installation, it was fairly straight forward. The hardest part is removing the fan/clutch assembly. I bought a large crescent wrench for the task. It might have been easier because the fan clutch was not the factory item. Remember that the threads are reversed, which means you loosen it by moving the handle of the wrench to the driver's side if the handle is pointing up. Before removing the fan all the way, I removed the two 8mm bolts at the top of the fan shroud, and then removed both components together.
The 40 kit comes with a fan shroud, but it leaves about a 1/2 inch gap between it and the radiator. A few washers fixed that so that the gasket material of the fan fits nicely up against the radiator, improving airflow dramatically. I also drilled a hole through the top of the shroud so the the factory clip for the air conditioning hose positioner would function.
There are several options for how this operates, including with/without ignition on, with A/C on, by a manual switch, and the non-optional when the radiator is too hot method. That last one does require that you stick a temperature probe through the radiator near the engine outlet, and that is admittedly a bit scary, but it worked.
As to those options, I have started just with the basic setup of on/off based solely on temperature. I didn't opt for the ignition option because most cars with electric fans don't use that option. I may switch, however, because it does cycle on and off quite a few times (about 6), but only for short periods of time. I like the idea though of cooling the area where the battery sits, so I may leave it. I will probably add the A/C option in the spring, but I really don't see the point of it when I'll just be using the A/C from here on out to defrost the windows during rain (I live in Seattle).
Anyway, I am concerned about reliability, because at a stop a boil over can start to occur in only about 5 minutes even in 60 degree weather. At the very least I'm going to carry an extra fuse. Moving at even 25 mph the fan never comes on in 60 degree weather, but that might not be the case at warmer temperatures.
As to airflow, I really doubt that's a problem if the fan is properly installed as described above. I have the fan set to kick on when the temperature gauge is at the "R" in word normal. It's base level is the "N" of normal. In 60 degree weather the temperature will drop back to the "N" in about 30-60 seconds, and that requires that water in the radiator be cooled and sucked into the engine since the gauge sensor is in the engine. So seemingly there's plenty of airflow. But again, to determine that for sure I need warmer weather. I would note, however, that with the A/C connection hooked up, the fan would be running more in warmer weather than when needed for engine coolant temperature control, so that would in effect be even more airflow. I would be more concerned if I did a lot of stop and go driving, or if I did a lot of off roading.
My final comment is the unit is slightly on the noisy side. You can definitely hear it turn on when you're at a stop. It's probably twice as loud as a factory fan.
Anyway, I'll try to update as time goes by.
Edit 10/11/09: 39 mph up the hill in fourth, not full throttle most the way. A huge difference from 47 and full almost all the way.
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