# fan and fan clutch



## Topkat (Sep 9, 2010)

My fan seems to be wobbling kinda bad. and I wanna replace it.
can I do away with the dam fan clutch?
btw, my indash tac didnt work when it started.........what might the probable cause be?
thanks as always


----------



## BearGFR (Aug 25, 2008)

Topkat said:


> My fan seems to be wobbling kinda bad. and I wanna replace it.
> can I do away with the dam fan clutch?


No no no no no! The clutch is your friend. It keeps the fan spinning at the rpm where it's most efficient at moving air. If that's where your wobble is, replace the clutch.



> btw, my indash tac didnt work when it started.........what might the probable cause be?
> thanks as always


Anything from a defective tach to a wiring problem. Check your Pertronix instructions for the proper way to connect the tach, and also make sure it has a good ground.

Bear


----------



## Topkat (Sep 9, 2010)

does the bi-metal go bad over the years?
how do I know the sucker is doing what it's supposed to?
ty


----------



## BearGFR (Aug 25, 2008)

Topkat said:


> does the bi-metal go bad over the years?
> how do I know the sucker is doing what it's supposed to?
> ty


They usually have two different failure "modes" --- one is that they get loose and don't turn the fan fast enough to move air efficiently, and start to wobble. In extreme cases they can come apart and airplane into to radiator, taking it out as well as the shroud, hoses, etc. The other way they fail is that they can lock up and spin the fan "too fast" to move air efficiently (yes that's possible). The wobblies are usually easy to spot because you'll be able to wobble the fan with your hands and see that the water pump shaft isn't moving but the fan is. The "tighties" are harder to identify - they're usually accompanied by excessive fan noise at rpm.

If yours is old and/or if you're not sure about it, replace it. What's the cost of a clutch compared to taking out the rest of the cooling system, or lunching your nice fresh motor due to overheating?

If it turns out you need a water pump too, then before you install the new pump put the sheet metal divider plate onto the pump body _without a gasket_ then carefully use a small hammer to "work" the plate so that it just barely touches the pump impeller. Then when you install the pump with a new gasket, the clearance between the impeller and the plate will be right where it needs to be for best cooling.

Bear


----------



## GTO JUDGE (May 14, 2005)

My '70 had the flex fan, although I had no hot issues I replaced it with a clutch fan when the motor was out of the car. Although the real temp test will come in 90* weather my temp gauge hangs at 165-170* when in motion. Haven't driven it yet beyond 60* air temp. I have a 165* high flow T-stat and use water wetter... Heater works great and warms fast.


----------



## geeteeohguy (Feb 2, 2008)

I had an extremely noisy flex fan on my '65 for over 25 years. Got sick of the noise last year and installed a factory clutch fan (oversized 19.5 inch, though) and a shroud. No more noise at all and the thing runs 15-20 degrees cooler. I have a big old 7 blade flex fan on the '67 that I robbed from a '69 Caddy 20 years ago (GM flex fan) and it works like a champ with no noise. I would recommend sticking with the stock or a slightly upgraded clutch set-up. The engineers got it right.


----------

