Fan Clutch Opinion Needed

[Tom Spurgeon]

My son and grandson are helping me with the restoration-assembly of a 1960 Corvette. The car came with a '57 (correct only) 283 engine, an incorrect rear end, frame, body - and that's all. We have re-worked the frame, had the body soda-blasted installed the correct rear end and have set the motor and a new T-10 transmission back on the chassis.

We have found that the fan blade that we purchased is designed for a spacer and direct mount to the waterpump pully and water pump. It is a five-blade fan and are concerned about overheating.

Knowing that the car will not be perfectly restored, but will appear stock, should we install a different fan blade that is designed for a fan clutch. Or, does the clutch make that much difference where overheating is concerned. And, if anyone knows, did the late 1960 come equipped with a fan clutch?

Thank you for your thoughts,
Tom Spurgeon

[Barbara S.]

Re: Fan Clutch Opinion Needed

Yes, the late '60 cars did have fan clutches. They were the same ones used on the very early '61 cars. Fred Oliva can probably help you find one, or check the Driveline. There are some good vendors in there.

I hope this helps! Good luck on your restoration.

Tony

[Barbara S.]

Re: Fan Clutch Opinion Needed

Yes, the late '60 cars did have fan clutches. They were the same ones used on the very early '61 cars. Fred Oliva can probably help you find one, or check the Driveline. There are some good vendors in there.

I hope this helps! Good luck on your restoration.

Tony

[Wayne C.]

Re: Fan Clutch Opinion Needed

My understanding of the purpose of the fan clutch is to spin the fan when the engine is at low speed (and/or the ambient air is warm) in order to move more cooling air through the radiator, but at high rpm (when plenty of cooling air is being forced through the radiator) the fan is allowed to slip/freewheel in order to avoid excessive fan noise and to save engine horsepower.

My circa 1976 parts manual calls for the same replacement 5-blade 17 1/8 dia fan and clutch for 60 through 67 Corvettes (actually, it says 60 "w/Fan Drive Equip"), so I assume at least some 60 Corvettes came with clutches. Strangely, there is no listing for a clutch or spacer for 57-59 Corvettes, nor is there a second fan type listed for the 60.

Actually, a direct-bolt fan probably keeps the engine at least as cool as one with a clutch, the difference probably being noise and wasted horsepower, other than a slight concern that a direct-bolt fan will hold together at high rpm. Given my druthers, I'd use a clutch.

[Wayne C.]

Re: Fan Clutch Opinion Needed

My understanding of the purpose of the fan clutch is to spin the fan when the engine is at low speed (and/or the ambient air is warm) in order to move more cooling air through the radiator, but at high rpm (when plenty of cooling air is being forced through the radiator) the fan is allowed to slip/freewheel in order to avoid excessive fan noise and to save engine horsepower.

My circa 1976 parts manual calls for the same replacement 5-blade 17 1/8 dia fan and clutch for 60 through 67 Corvettes (actually, it says 60 "w/Fan Drive Equip"), so I assume at least some 60 Corvettes came with clutches. Strangely, there is no listing for a clutch or spacer for 57-59 Corvettes, nor is there a second fan type listed for the 60.

Actually, a direct-bolt fan probably keeps the engine at least as cool as one with a clutch, the difference probably being noise and wasted horsepower, other than a slight concern that a direct-bolt fan will hold together at high rpm. Given my druthers, I'd use a clutch.

[Joe L.]

Re: Fan Clutch Opinion Needed

Wayne and Tom-----

Yup, that's pretty much how it is. A direct drive fan will move as much air (i.e. cool) as a viscous drive fan clutch "on it's best day". There's absolutely no compromise to cooling using a direct drive. As Wayne mentioned, what you get with direct drive is more noise and some wasted horsepower. If those are not issues for you but maximum cooling is, then you have what you need right now.

If you wish to use a fan clutch, then you can use fan GM #3770529 (still available and $70.67 GM list) and fan clutch GM #3916141 (may or may not be still available and carries GM list of $196.70 if it is). You could also use an aftermarket THERMAL-style fan clutch which would be a lot cheaper than the GM unit, but not as "correct" in terms of configuration.

[Joe L.]

Re: Fan Clutch Opinion Needed

Wayne and Tom-----

Yup, that's pretty much how it is. A direct drive fan will move as much air (i.e. cool) as a viscous drive fan clutch "on it's best day". There's absolutely no compromise to cooling using a direct drive. As Wayne mentioned, what you get with direct drive is more noise and some wasted horsepower. If those are not issues for you but maximum cooling is, then you have what you need right now.

If you wish to use a fan clutch, then you can use fan GM #3770529 (still available and $70.67 GM list) and fan clutch GM #3916141 (may or may not be still available and carries GM list of $196.70 if it is). You could also use an aftermarket THERMAL-style fan clutch which would be a lot cheaper than the GM unit, but not as "correct" in terms of configuration.

[Dave Suesz]

[Dave Suesz]

[Fred Oliva]

Re: Fan Clutch Opinion Needed

In addition to what Joe said, the aftermarket thermal clutches use really cheap components. Especially the seal & bearing assembly. I would invest in a GM clutch.

[Fred Oliva]

Re: Fan Clutch Opinion Needed

In addition to what Joe said, the aftermarket thermal clutches use really cheap components. Especially the seal & bearing assembly. I would invest in a GM clutch.

[Craig S.]

Re: Fan Clutch Opinion Needed

And you can get the GM one Joe shows list for $196 from GM parts direct for $112 plus shipping bringing total to $134.....Craig

[Craig S.]

Re: Fan Clutch Opinion Needed

And you can get the GM one Joe shows list for $196 from GM parts direct for $112 plus shipping bringing total to $134.....Craig

[Jim #42767]

Re: Fan Clutch Opinion Needed

Are you saying you would buy one from GM over Paragon?

[Jim #42767]

Re: Fan Clutch Opinion Needed

Are you saying you would buy one from GM over Paragon?