Catalog

VOLVO 30667067 PULLEY ALTERNATOR

VOLVO 30667067 PULLEY ALTERNATOR

Product Specifications

Product quality
OEM Equivalent Grade
starstarstar
Wholesale price USD $7.97
Wholesale price CNY ¥54
bolt MOQ (Minimal order)
50 pcs
local_shipping Production time
25-45 days
package_2 Shipping Weight: —
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VOLVO 30667067
VOLVO 8666579
Overview & Operating Principle
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The PULLEY ALTERNATOR is an alternator overrunning clutch pulley — also called a decoupler pulley or OAP (overrunning alternator pulley) — that replaces the conventional solid alternator pulley on modern engine accessory drive systems to isolate the alternator's rotor inertia from the accessory belt during deceleration events, eliminating the belt vibration and noise that a solid pulley would transmit during rapid engine speed changes. The mechanism integrates a one-way roller or sprag clutch element and a torsional spring damper inside a conventional poly-V pulley shell: the one-way clutch engages the alternator shaft in the drive direction — transmitting torque from the belt to the alternator rotor during acceleration and steady-speed driving — but freewheels in the overrun direction, allowing the belt to decelerate faster than the alternator's rotor during engine deceleration without transmitting the rotor's inertia back to the belt. This decoupling function eliminates the brief but repetitive tensile overload in the accessory belt that a solid pulley would impose each time the engine decelerates from an injection cut or during normal throttle closure — overloads that cause belt slip, rapid tension spring fatigue in the belt tensioner, and a characteristic chirping or squealing noise on deceleration. The integral torsional spring damper absorbs the cyclic torque pulses of the engine's firing order that propagate through the crankshaft to the accessory belt, providing additional isolation from low-frequency torsional vibration that reduces belt fatigue and suppresses accessory drive resonance on modern stop-start equipped engines where the accessory belt must reverse direction at each engine restart.

This unit — VOLVO 30667067 — is manufactured to OEM-equivalent specifications: pulley outer diameter and poly-V groove profile for the accessory belt specification, overrunning clutch engagement torque and freewheel direction, torsional spring rate and damping characteristic, alternator shaft thread size and bore profile for the torque tool engagement, and overall assembly width for correct belt alignment are matched to the original part. Supplied as a complete assembly ready for installation. Available wholesale from 7.97 USD, MOQ 50 pcs, production lead time 25-45 days.

Overrunning alternator pulleys fail through one-way clutch bearing wear that produces increasing freewheel drag — as the clutch rollers or sprags wear, they begin to transmit some of the rotor's inertia back to the belt during deceleration, progressively reproducing the belt noise and vibration that the pulley was designed to eliminate; through torsional spring fatigue that reduces the spring's torque capacity below the engine's firing order pulse amplitude, causing the pulley to rattle at idle; and through complete clutch seizure that locks the pulley solid and converts it to a standard non-decoupling pulley — a condition that causes immediate belt squealing on deceleration and rapid accessory drive tensioner wear.

Symptoms & Diagnostics
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Chirping, squealing, or brief belt noise specifically on engine deceleration — the noise occurs in the 2–3 seconds after the throttle is released or the engine speed drops and disappears at steady idle — the overrunning clutch has partially or completely seized; the belt is being loaded by the alternator rotor's inertia during deceleration; confirm by gently touching the running belt with a belt dressing spray — if the noise temporarily stops, belt slip is occurring at the alternator pulley; if the noise is unaffected, the source is a bearing squeal at the pulley.
Rattling noise from the alternator pulley at idle — a mechanical clicking or rattling that varies with engine RPM at low speed and disappears above 1,500 RPM — the torsional spring damper inside the pulley has fatigued and can no longer absorb the engine's low-frequency firing order pulses; the spring element is bottoming against its travel stop and producing impact noise; the noise is most prominent at idle where the firing order pulses are slowest and the spring must absorb their full amplitude.
Accessory belt wear — fraying edges, glazed ribs, or rib cracking — at mileage significantly below the belt's expected service life — a seized overrunning pulley is causing repeated belt microslip events on every deceleration; each slip event partially glazes the belt rib surface and generates heat; the cumulative effect is a belt that has aged from heat and slip at a fraction of its normal life; replace the belt simultaneously with the overrunning pulley.
Accessory drive tensioner spring that has collapsed or lost its preload — tensioner at or near its minimum travel position despite a new belt — a seized overrunning pulley converts each engine deceleration into a tensile overload of the accessory belt circuit; these repeated overloads exceed the tensioner spring's design fatigue limit and cause progressive spring relaxation; replace the tensioner and overrunning pulley simultaneously.
Confirmed freewheel function test failure — the pulley rotates in both directions with equal resistance when rotated by hand with the belt removed — a functional overrunning pulley freewheels smoothly in one direction and engages with progressive resistance in the other; equal resistance in both directions confirms clutch seizure; zero resistance in both directions confirms complete clutch failure; either condition requires immediate replacement.
Battery charge warning light combined with accessory belt squealing on deceleration — the alternator is undersupplying charge current — a severely worn overrunning clutch that has excessive freewheel drag is allowing the alternator rotor to slip relative to the belt under load, reducing the rotor speed below the minimum required for adequate charge output; the charge light illuminates when the rotor slip prevents sufficient current generation to maintain battery voltage.
Logistics & Customs
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International HS Code
8483.50
EAEU Customs Code (TN VED)
8483 50 809 0
Typical Net Weight
Country of Manufacture
China
Standard MOQ
50 pcs
Production Lead Time
25-45 days
Always verify the exact 8-digit or 10-digit subheading with your customs broker for the destination country, as tariff schedules and duty rates vary by jurisdiction.
Installation Tips
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  1. Use the correct OAP removal and installation tool for the specific alternator shaft thread — overrunning alternator pulleys have a left-hand or right-hand thread depending on the application, and an internal hex or Torx profile in the shaft bore that requires a matching tool to hold the alternator shaft stationary while the pulley is rotated; attempting to remove the pulley by gripping the pulley outer shell with pliers crushes the aluminium shell and destroys the pulley before removal; the correct tool set is application-specific and must be confirmed from the OEM service data before beginning removal.
  2. Confirm the thread direction — left or right hand — before applying removal torque — the pulley installation direction is designed to self-tighten under normal belt drive torque; on most applications with a clockwise-rotating alternator shaft the pulley has a left-hand thread; applying removal force in the wrong direction attempts to tighten an already-installed pulley and risks stripping the alternator shaft thread or damaging the rotor bearing; confirm the thread direction from the OEM service data or from markings on the old pulley body before applying any force.
  3. Clean the alternator shaft thread and seating face before installing the new pulley — remove all corrosion and debris from the shaft thread using a thread chaser of the correct pitch; any debris on the shaft seating face prevents the new pulley from torquing down fully and may allow the pulley to work loose under operation; apply a thin film of clean engine oil to the shaft thread for consistent torque-to-clamp conversion.
  4. Torque the new pulley to the OEM specification using the correct shaft-holding tool — typical overrunning pulley torque values are 50–80 Nm; the shaft-holding tool must be engaged in the alternator shaft bore throughout the entire torquing process to prevent the torque wrench force from being absorbed by the alternator's rotor bearing rather than the thread engagement; a bearing subjected to the full tightening torque without shaft restraint will fail from the side load within a short operating period.
  5. Verify the new pulley's freewheel function before refitting the accessory belt — with the pulley installed on the alternator shaft, rotate the pulley shell in both directions by hand; in the drive direction the shell should engage the shaft with progressive resistance within a few degrees; in the freewheel direction the shell should spin freely with only light bearing drag; a pulley that resists in both directions has been installed incorrectly or is the wrong part number.
  6. Install the new PULLEY ALTERNATOR (VOLVO 30667067), refit the accessory belt and tension to OEM specification, start the engine and confirm the deceleration noise has been eliminated, road test with several sharp throttle closures at 3,000 RPM confirming no belt squeal on deceleration, and verify correct battery charge voltage (13.8–14.4V) under electrical load before returning the vehicle to service.
Tools: OAP removal and installation tool set (application-specific inner hex or Torx and shaft-holding adapter), torque wrench (50–80 Nm), thread chaser for alternator shaft, voltmeter for charge voltage verification after installation.
Frequently Asked Questions
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How can the overrunning alternator pulley be confirmed as the source of accessory belt noise before parts are ordered?
The definitive field test for a failed overrunning alternator pulley is the freewheel check performed with the engine off and the accessory belt in place: grasp the alternator pulley and attempt to rotate it by hand in both directions — a functional overrunning pulley rotates freely in the freewheel direction (typically clockwise when viewed from the pulley face) with only light bearing drag; in the drive direction it engages within a few degrees and requires significant force to continue rotating. A seized pulley requires equal force in both directions; a failed clutch pulley rotates freely in both directions. If a bench check with the belt removed is not practical, start the engine at idle and observe the accessory belt run for any vibration or slack waves on the belt span approaching the alternator pulley — an OAP that is correctly freewheeling during deceleration produces a momentary slack wave in the belt on deceleration as the belt speed drops while the alternator rotor continues at its previous speed; absence of this characteristic slack wave confirms a seized pulley. ok.parts supplies overrunning alternator pulleys at wholesale MOQ from 7.97 USD per unit.
Should the overrunning alternator pulley be replaced with a standard solid pulley if an OAP is not immediately available?
Substituting a solid pulley as a temporary measure is possible but produces immediate accessory drive system effects that can cause secondary failures. A solid pulley on an engine calibrated for an OAP imposes repeated tensile overloads on the accessory belt and tensioner spring on every deceleration event — the tensioner's spring was designed for the reduced belt loading that the OAP provides, and solid-pulley overloads will cause rapid tensioner spring relaxation and belt rib glazing within a short operating period. On stop-start equipped vehicles the solid pulley imposes additional reverse-direction belt loading on every restart that the OAP was specifically designed to absorb. If a temporary solid pulley must be used, the replacement OAP should be fitted as soon as available, with a new accessory belt and tensioner if the interim period has been extended.
How does the OEM-equivalent aftermarket unit compare to the genuine OEM part?
OEM-equivalent units in this catalogue replicate the current OEM design geometry and material specification. Quality is verified against OEM cross-reference data. When ordering in bulk, confirm with our team that the specification matches the latest OEM revision for your application.
Is white-label or custom packaging available for wholesale orders?
Yes. ok.parts works directly with the manufacturing facility and can accommodate neutral white-label packaging or fully branded packaging with your company logo, part numbers, and barcode. Minimum order quantities and lead times for custom packaging may differ from standard stock. Contact the team via the inquiry form to discuss your specific requirements.
Frequently Replaced Together
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PartReason for Combined Replacement
Accessory Drive Belt (Poly-V Belt)
OEM length and rib count — application-specific		A seized overrunning pulley causes belt microslip on every deceleration event, progressively glazing the belt rib contact surfaces and generating heat that accelerates rubber degradation. A belt that has been running against a seized OAP for thousands of kilometres has glazed ribs that will slip on the new pulley under electrical load and cause chirping noise from the first drive — replacing the belt simultaneously with the pulley ensures the new OAP operates against unglazed belt ribs from the first engagement.
Accessory Drive Belt Tensioner
Spring-loaded automatic tensioner — OEM ref. varies		Repeated tensile overloads from a seized OAP cause the automatic tensioner's coil spring to relax below its designed preload, reducing belt tension and allowing belt microslip under peak electrical demand. A tensioner that is at or near its minimum travel position despite a correctly routed belt has been overloaded by the seized pulley. Replacing the tensioner simultaneously with the OAP and belt restores the complete accessory drive system to a consistent new condition with matched spring preload and belt friction characteristics.
Alternator
OEM ref. varies by engine electrical system		An overrunning pulley that has seized completely — rotating the alternator shaft in the freewheel direction as well as the drive direction — has been subjecting the alternator's front bearing to reverse-direction loading on every deceleration event. With the pulley removed, rotate the alternator shaft by hand and assess bearing smoothness; a rough or noisy bearing from reverse loading requires alternator replacement alongside the new OAP to prevent a bearing failure that would strand the vehicle from a loss of charge within a short interval.