Email between Mike and I:

Hi Again.

1. You do not necessarily need a clutch on a fixed fan, however it in addition to the reasons I mentioned in the post (i.e. HP loss, and noise), it is also easier on the water pump pulley especially at high engine RPM, where any imbalance in the fan is magnified. Additionally, fans designed to run with a clutch generally have a steeper pitch than fans designed to run direct. This results in their being able to pull more air when the clutch is locked than a normal direct drive fan.

2. Absolutely. Unless you have a fan I haven't seen before (I read your post were your explained the fan you have, and I know the fan your referring to) the aftermarket units flatten out at a lot lower RPM (even a little at Idle) reducing their effectiveness. The Ford fans have a little steeper pitch, and are made a little stiffer, which is why I would use one of those over the aftermarket type, if I couldn't run a clutch.

3. A good shroud is CRITICAL, I didn't spend a lot of time addressing this as Bob had already pretty much covered it. All of the cooling system components must work together, a good fan AND fan shroud should make all the difference in the world as far as cooling.

4. The "Tricks" your mechanic mentioned are RACE CAR ONLY things, that are NOT RECOMMENDED for street driven cars. A car that only see a 1/4 mile at a time require different things than car that is used to go up and down the street. My main concern is that he recommended things that will only make a very insignificant impact on the cooling problem. After the timing was set correctly and the car still overheated, he should have quickly diagnosed the likely problem as the fan/fan shroud/electric fan and explained this to you rather than trying all this other stuff. Chances are when this didn't work, you would have still been down to putting a fan and shroud on it. By the way were you going to have him put the shroud on at the same time he did this other stuff. If you were the shroud would be what would make the difference, not the advance limiter and then the starter saver.



PS Als suggestion about checking the radiator cap is a good suggestion and example of that I just said.


Mike