PAI 1645B Engine Cooling Fan Clutch + Cross Reference

PAI 1645B Part Description

Manufacturer

Features & Benefits

Hub diameter of 2.56 in. presents a compact mounting face
Fan pilot diameter of 5 in. aligns with standard fan centers
Overall height of 4.19 in. supports tight engine bay spacing
Accepts fan diameters up to 26 in. for broad airflow coverage
Metal housing offers a solid weight and substantial feel

PAI Engine Cooling Fan Clutch

The PAI Engine Cooling Fan Clutch manages airflow across the radiator by controlling when the engine-driven fan engages based on operating conditions. During low cooling demand, the clutch allows the fan to slow, reducing unnecessary airflow. As temperatures increase, internal mechanisms allow the fan to engage more fully, increasing air movement through the cooling stack. This engagement process responds automatically to heat levels generated during engine operation, particularly under load or extended idle periods. Used on Mack E7 engine platforms, the clutch functions as an active airflow regulator rather than a fixed-drive component. The PAI 1645B enables controlled fan engagement to match cooling needs during operation.

PAI 1645B Specifications

Product Attributes

Notes

Fan Clutch Hub diameter: 2.56in Fan Pilot diameter: 5in Height: 4.19in Maximum Fan diameter: 26in Mack E7 Engine application

PAI 1645B Cross References

Brand	Part Number
	MAK38MH414M, EFC-1645B, 38MH414M
PAI	EFC-1645B

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PAI 1645B Manufacturer Information

Backed by 40 years of part manufacturing experience, PAI Industries® has been providing the heavy-duty truck industry with high-quality service parts for the engine, gearing, exhaust, suspension, and electrical systems. This brand has been manufacturing its products in the USA since 1973, and it owes its worldwide success to its dedicated and experienced employees. PAI takes pride in being an ISO 9001:2015-certified auto and truck parts manufacturer, operating in a 54,000 square feet facility that is equipped with state-of-the-art machinery. PAI’s technicians also perform 100% testing and inspection in its oil pump, water pumps, gear, synchronizer, and cylinder head to ensure durability and reliable performance.