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The 1972 base 350 convertible I recently purchased does not have a fan clutch. I haven’t driven the car very much since I got it home, I’m fixing all the systems and pieces that have been neglected for the past 30 years. It didn’t overheat when I drove it 40 highway miles home. My factory Assembly M
anual shows it as having a fan clutch. Do you all think I should invest in a fan clutch or just drive it as is and see where my temp is at?
Hello. Just saying that if you do get one you may not want a "heavy duty" one. i replaced mine a couple of years ago and got one that was classified as heavy duty. When taking off from a start it sounded like a truck/bus because of the clutch fan, put a regular service one on and it's much better. Now you can hear the normal car not just the clutch fan at work.
IMO, that looks like a fan clutch eliminator kit used with the stock fan. I would get a fan clutch first. Also, if your going to look for the parts by GM part numbers, the correct GM part #'s for a 1972 L48 with no A/C is 460472 for the clutch and the fan blade is 3991420.
On the highway, if everything else works, you don't need a fan at all. The real test is stop and go traffic, which electric fans can often handle better.
Positioning of the fan blades in relation to the shroud is critical. You don't want the fan too far inside or too far back where its doing nothing.
I believe the general rule is: two thirds (2/3) inside the shroud.
Looks like yours is spot-on.
If you add a clutch, you will likely have to remove that fan hub you have now, to get the proper spacing.
I would put some miles on the car before I messed with it, so you get sort of a base line as to how it's working. Then if you add the clutch you will be able to know the difference between the two. Who knows why the PO went with a solid fan, could be a cooling issue or just someone told him it was better for some reason... The fan is not he only thing drawing HP, the Alternator also does and when you add a high draw item like electric fans that goes up substantially, there is no free lunch!
Positioning of the fan blades in relation to the shroud is critical. You don't want the fan too far inside or too far back where its doing nothing.
I believe the general rule is: two thirds (2/3) inside the shroud.
Looks like yours is spot-on.
If you add a clutch, you will likely have to remove that fan hub you have now, to get the proper spacing.
should be half in or half out depending how you like to look at it
i found the replacement not the same as original.
mine was all in shroud except half inch out, the new ne would pull it back almost another day inch.
I wound up fxing my old clutch in thread bot would be kinda cool to get exact measurements for your car..
i would put a clutch in. If it verheats with clutcg, something else is wrong.
Agree woth heavy duty i tried..really noticed drag and noise..i can only imagine how much power lost if i could feel the heavy duty vs standard hp clutch.
Thanks for posting the diagrams and a part number @interpon!
The OP would do well to use that, and get on the road quickly.
Using electric fans, like every Corvette has since 1983, has a host of other benefits, not least is more space under the hood, and not having a spinning wheel of death 6 inches from your face when trying to see the timing mark on your harmonic damper. But doing it "right" is rather involved, and will likely require a new alternator and some wiring.
I'm also happy to concede that there are more ways for electric fans to fail. This is why I have two, on two circuits, with no single point of failure. But if they do fail, you know immediately. Hopefully fan clutches fail "safe", and continue to spin vs. freewheel, as you would have very little indication of that happening, other than overheating at idle.
Here's a thread with more discussion on the topic, that doesn't have this Forum's usual suspects.
Fan clutch missing?
