Derale Aluminum Belt Fan Spacer 1.5" — Female 5/8–3/4" Pilot, Anodized, Includes 5/16" Hardware

Derale 31515 is a 1½-inch anodized aluminum belt fan spacer with a female 5/8–3/4" pilot designed to position belt-driven fans securely and reduce wobble.

This compact spacer relocates the fan away from the mounting surface to improve alignment, clear obstructions, and simplify belt routing in engine bays and cooling setups. Machined from lightweight aluminum and finished with a clear anodize, it resists corrosion while keeping weight low. The unit ships with both fine and coarse 5/16" threaded hardware so it fits common fan and pulley combinations without extra parts.

How does this spacer improve fan alignment and belt routing?

The Derale 31515 creates precise separation between the fan and the mounting surface, helping bring the fan centerline in line with pulleys and reducing belt strain. Proper spacing prevents rubbing and uneven belt wear, which extends component life and maintains consistent airflow from the fan.

• 1.5" length corrects common offset and clearance issues
• Female 5/8–3/4" pilot centers the fan for accurate runout
• Anodized aluminum reduces corrosion where belts and pulleys operate
• Includes both fine and coarse 5/16" hardware for versatile fits

What vehicles and applications is the spacer compatible with?

The spacer is suitable for many belt-driven electric and mechanical fans used in automotive, light truck, and custom cooling setups where a 5/8–3/4" pilot is standard. Because it’s a universal-style spacer rather than a vehicle-specific part, it works well for custom mounting, radiator shrouds, and fan relocations.

• Fits most fans with a 5/8" to 3/4" mating pilot
• Useful for custom and retrofit fan installations
• Common in performance, restoration, and maintenance projects
• Lightweight design avoids adding unnecessary mass to assemblies

What materials and hardware come with the spacer?

The Derale 31515 is machined from aluminum and finished with a clear anodize that helps resist surface oxidation. The package includes both fine-thread and coarse-thread 5/16" fasteners so you can match the existing fan or pulley threads without sourcing separate bolts.

• Aluminum body for low weight and strength
• Clear anodized finish for corrosion resistance
• Supplied fine and coarse 5/16" threaded hardware for flexibility
• Female pilot sized 5/8" to 3/4" for secure centering

How do I install the spacer safely and effectively?

Installation is straightforward: remove the fan mounting bolt, slide the spacer onto the mounting stud or bolt, align the fan on the spacer pilot, and reinstall using the supplied 5/16" hardware. Verify clearance and spin the assembly by hand before running the engine to check for contact or imbalance.

• Hand-thread bolts first to avoid cross-threading
• Confirm the pilot seats fully for accurate centering
• Check belt tension and fan-to-shroud clearance after install
• Re-torque hardware to manufacturer specifications

Who this is for: The Derale 31515 spacer suits mechanics, fabricators, and DIY enthusiasts needing a reliable, low-profile solution to correct fan offset or to achieve desired clearance in custom cooling installations. If you’re aligning belt-driven fans, retrofitting aftermarket fans, or preventing belt contact with engine components, this compact, anodized aluminum spacer provides a durable, easy-to-fit option without adding excess weight.