Why You Need a Fan Shroud

Click Here to Begin Slideshow No one likes a car that overheats. That’s a no brainer. But when it comes to cooling you absolutely must first figure out a way to bring the air to the radiator (cooler). The idea is of course to provide a constant supply of air through the radiator so that the coolant is reduced in temperature. Increasing the airflow through the radiator improves the cooling and as a result, a shroud is almost mandatory on high performance applications. Unfortunately, they are often missing on any number of older cars. Keep in mind that shrouds are often manufactured from plastic and as result, the condition typically degrades dramatically over the years. If you don’t have a shroud or if it fits poorly, get the right one (that's a big hint if you end up sitting behind Old Faithful on a regular basis). How does the shroud work? Basically, the shroud surrounds or partially surrounds the fan. It butts up tightly to the face of the radiator, effectively sealing the cavity. This isolates the pocket of air behind the radiator, allowing the fan to efficiently draw the required air through the radiator. If the shroud is not present, it creates a considerable amount of "dead" space behind the radiator that in turn destroys the effectiveness of the fan assembly. The bottom line is simple: If you don't run a proper shroud, you're only asking for overheating grief. So where do you find shrouds for older cars? That’s simple too: The restoration aftermarket is loaded with quality reproduction shrouds for all sorts of applications. They work. That’s not the end of it though. In the case of electric fans, you usually have two options: A pusher fan and a puller fan. Motor vehicle manufacturers have used both configurations in modern passenger cars and light trucks, although puller fans are the most common. Sometimes electric fans are used in conjunction with an engine driven clutch fan (typically, an electric pusher fan mounted ahead of the rad). This arrangement is particularly useful if heavy cooling tasks are mandated by the application. A good example is a pickup truck with a factory towing package. This might be a good choice for a car that's either blessed with a cooling dilemma or one that sees double duty as a weekend racer. Companies such as Ron Davis Racing Products have spent considerable time researching cooling fans with these criteria. Davis offers a trio of fans – 12-inch, 14-inch and 16-inch diameters. Specs are as follows: Part Number Diameter RPM CFM EF 120 12-inch 2300 1576 EF 140 14-inch 2400 1828 EF 160 16-inch 2400 2197 All of the above have a low amp draw, but Davis points out that one of the other secrets to properly cooling a high performance car is to effectively seal the radiator to the fan. Typically, this is accomplished by way of an integral shroud surrounding the electric fan. The shroud simply allows the largest volume of air to be pulled through the rad (typically in a pull through application). There’s more too: If you take the time to effectively seal any gaps between the fan shroud and the radiator, cooling can improve. It’s not that difficult to accomplish – see the accompanying photos for a closer look.

Why You Need a Fan Shroud

Click Here to Begin Slideshow

No one likes a car that overheats. That’s a no brainer. But when it comes to cooling you absolutely must first figure out a way to bring the air to the radiator (cooler). The idea is of course to provide a constant supply of air through the radiator so that the coolant is reduced in temperature. Increasing the airflow through the radiator improves the cooling and as a result, a shroud is almost mandatory on high performance applications. Unfortunately, they are often missing on any number of older cars. Keep in mind that shrouds are often manufactured from plastic and as result, the condition typically degrades dramatically over the years. If you don’t have a shroud or if it fits poorly, get the right one (that's a big hint if you end up sitting behind Old Faithful on a regular basis).

How does the shroud work? Basically, the shroud surrounds or partially surrounds the fan. It butts up tightly to the face of the radiator, effectively sealing the cavity. This isolates the pocket of air behind the radiator, allowing the fan to efficiently draw the required air through the radiator. If the shroud is not present, it creates a considerable amount of "dead" space behind the radiator that in turn destroys the effectiveness of the fan assembly. The bottom line is simple: If you don't run a proper shroud, you're only asking for overheating grief. So where do you find shrouds for older cars? That’s simple too: The restoration aftermarket is loaded with quality reproduction shrouds for all sorts of applications. They work.

That’s not the end of it though. In the case of electric fans, you usually have two options: A pusher fan and a puller fan. Motor vehicle manufacturers have used both configurations in modern passenger cars and light trucks, although puller fans are the most common. Sometimes electric fans are used in conjunction with an engine driven clutch fan (typically, an electric pusher fan mounted ahead of the rad). This arrangement is particularly useful if heavy cooling tasks are mandated by the application. A good example is a pickup truck with a factory towing package. This might be a good choice for a car that's either blessed with a cooling dilemma or one that sees double duty as a weekend racer.

Companies such as Ron Davis Racing Products have spent considerable time researching cooling fans with these criteria. Davis offers a trio of fans – 12-inch, 14-inch and 16-inch diameters. Specs are as follows:

Part Number Diameter RPM CFM
EF 120 12-inch 2300 1576
EF 140 14-inch 2400 1828
EF 160 16-inch 2400 2197

All of the above have a low amp draw, but Davis points out that one of the other secrets to properly cooling a high performance car is to effectively seal the radiator to the fan. Typically, this is accomplished by way of an integral shroud surrounding the electric fan. The shroud simply allows the largest volume of air to be pulled through the rad (typically in a pull through application). There’s more too: If you take the time to effectively seal any gaps between the fan shroud and the radiator, cooling can improve. It’s not that difficult to accomplish – see the accompanying photos for a closer look.

Why You Need a Fan Shroud 1

A tight fitting OEM style shroud such as this is a big key to keeping your car cool. Typically, the fan blade tips will be very close to the edge of the shroud. What this does is to direct all incoming air through the radiator. This particular example is from Classic Industries.

Why You Need a Fan Shroud 2

Good reproduction fan shrouds have tabs molded in on each side.

Why You Need a Fan Shroud 3

They are designed to accept a set of clips that affix the shroud to the radiator (just like the factory did in the sixties and seventies).

Why You Need a Fan Shroud 4

Upstairs, the shrouds typically mount to a bracket, which is in turn affixed to the radiator support. The top bracket is what keeps the shroud in place while the side tabs (with clips) keep the shroud tight against the rad.

Why You Need a Fan Shroud 5

There is any number of ways to make use of an electric fan. You can use a single fan as a pusher, mounted in front of the radiator. This format only works if it’s used in conjunction with a regular engine driven fan.

Why You Need a Fan Shroud 6

Another option is to fit a pair of puller fans to the backside of the radiator. With this arrangement, be sure the plastic shroud fits tightly.

Why You Need a Fan Shroud 7

Even though the fans overlap the sides of this radiator, the tight fitting aluminum shroud directs all of the air through the rad. As you can see, everything on the rad backside is covered. This setup is from Ron Davis Racing Radiator. Not only is it good-looking, it flat works!

Why You Need a Fan Shroud 8

On this car, the rad support was opened up by way of die grinder to allow for more air to flow through the radiator. In this case, the stock small block Nova radiator support had an embossed outline of a big block opening. You can simply trim it back to copy the opening for a big block rad. Presto: More cooling capability.

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