'64 Fan Shroud/Fan Clutch

[Mark H.]

If I stand on the side of the engine compartment (1964 L75) and look down past
the fan to the bottom of the radiator, I can see daylight - maybe 1/2 inch -
between the bottom of the radiator and the front lip of the shroud. How close
should they be? I see no seals shown in the AIM, other than the "flap" that
attaches to the bottom of the shroud with some wire staples (which I have in
place). I don't seem to be getting enough air flow past the radiator (new
DeWitts) - she hovers between 180 and 220 while moving, but at a light begins
to climb rapidly. The coolant is full (pulled the thermostat housing this
afternoon and got coolant everywhere) and the thermostat is working. My other
thought is the fan clutch - I see no real difference in how hard it is to turn
by hand when it is cold, or just after shut down when fully hot.

Any ideas?

[Wayne P.]

Re: '64 Fan Shroud/Fan Clutch

Sounds like you need a fan clutch.

[Scott Butville]

Re: '64 Fan Shroud/Fan Clutch

I'd verify the gauge with an IR gun before I spent another dime. The best way to evaluate the fan clutch is to count the number of turns the fan makes after the engine is shut off when it is up to temperature. A piece of tape on one of the fan blade tips helps. Any more than 5 turns calls for replacement. You can also remove the clutch as a test.

[Les Jacobs]

Re: '64 Fan Shroud/Fan Clutch

I agree with the IR gun suggestion. I wasted a lot of time and energy (and bucks) trying to cure a heat problem caused by a out of calibration gauge. PS I have an extra fan clutch.

[Mark H.]

Re: '64 Fan Shroud/Fan Clutch

Thanks. I've never used one of these IR guns. do you just take readings at various spots on the cylinder case and heads to see the max reading? What is the high end of acceptable? 200? 210?

[Les Jacobs]

Re: '64 Fan Shroud/Fan Clutch

Hey Mark While I've aimed it all over the place just out of curiosity, the recommendation from the board seems to be to focus on the thermostat housing. Its fairly close to the temp sender, so it "should" agree with the gauge. (Mine was off by almost 40 degrees) Re the acceptable temp.. it depends on a number of variables (ambient, pressurized radiator cap, operating condition , accesories etc), and mine ranges from slightly above the thermostat temp (180) if the car's been moving on a cool day, to 210 or slightly higher on a hot day stuck in traffic w/0 AC). I believe Ive read in the archives that the system can actually handle up to 240 degrees (which would make me crazy). Good Luck Les