3970945 Engine Drive Belt Idler Pulley For QSB6.7 QSB5.9 6.7L 5.9L

A belt tensioner is a device that applies a predetermined amount of tension to the engine's accessory drive belt (serpentine belt). Its primary function is to maintain constant, optimal tension on the belt as it wears and stretches over time. This prevents the belt from slipping, squealing, or throwing off, ensuring that critical components like the alternator, water pump, and A/C compressor operate reliably. This belt tensioner 3970945 is engineered for maximum durability and precise fitment in QSB6.7 QSB5.9 6.7L 5.9L engines. Manufactured to meet or exceed OEM standards, it ensures optimal engine performance and a long service life under heavy-duty conditions.

Whether for full engine rebuilds or quick replacements, DDP Engine provides you with the most reliable parts at unbeatable wholesale prices.

Parameter Details
Product Name: Belt Tensioner
Part Number: 3970945

Condition: Brand New / High-Quality OEM / Aftermarket
Warranty: 6 Months / 1 Year
Engine Model: QSB6.7 QSB5.9 6.7L 5.9L

Application:

QSB6.7 (6.7L): Commonly used in medium and large excavators (such as 305LC-9, EX200-7), loaders, road rollers, concrete pump trucks, and medium-to-high power generator sets (160–230 kW), with rated power typically 130–194 kW (175–260 hp). It is matched with a high-pressure common rail system, balancing power and emissions compliance.

QSB5.9 (5.9L): Primarily used in small excavators (such as PC200-7, 320D), light construction machinery, fire pump trucks, oilfield vehicles, and low-power generator sets (90–130 kW), with rated power approximately 110–180 kW (150–240 hp). It features a compact structure and lower cost; some models (such as QSB5.9-C180) are alternatives to the China III emission standard.

Why Choose DDP Engine:
100% Quality Guaranteed: All parts undergo rigorous testing to ensure perfect compatibility and premium performance.
Fast Worldwide Shipping: Large inventory in stock. Orders are typically processed within 3-7 working days with reliable global express and Transportation.
Professional Technical Support: Unsure about the part number? Contact our engineering team for exact cross-reference matching.
Flexible Solutions: Providing Genuine, OEM, and premium Aftermarket spare parts to fit your budget.