Rattle Noise From Primary Chain Drive on Ford 4.0L SOHC Engine - Engine Builder Magazine
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Rattle Noise From Primary Chain Drive on Ford 4.0L SOHC Engine


The 4.0L SOHC engine is one of Ford’s Cologne V6 engines, a line of 60º, cast iron block, V6 engines produced continuously by Ford in Cologne, Germany since 1968. It uses a jackshaft in place of a camshaft to drive a timing chain to each cylinder head. The patented "Offset Y-drive" uses three timing chains, one from the crank to the jackshaft, one inthe front of the engine to drive the cam for the left bank, and one on the back of the engine to drive the cam for the right bank.

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Some vehicles equipped with the 4.0L SOHC engine may exhibit a Primary Timing Chain rattle noise. The noise is audible during hot and cold engine operation (but predominantly found on cold engines) under acceleration, typically at 2,400-2,500 rpm. To confirm presence of this noise, accelerate in 2nd gear between 2,000-3,000 rpm and listen for rattle noise that sounds similar to spark knock. This may be caused by the Primary Timing Chain Tensioner system.


Replace the Primary Timing Chain Tensioner, Chain Guide, Jackshaft, and Crankshaft Sprockets with a Primary Timing Chain Tensioner Kit. The kit includes an improved Primary Chain Tensioner, as well as updated Primary Chain Guide, Jackshaft, and Crankshaft Sprockets. Required fasteners, primary timing chain, and front cover gaskets are also included. Refer to the following Service Procedure for details.


Service Procedure:

Verify the condition. Obtain the correct kit and follow the sheet supplied with the kit.

Use kit 2U3Z-6D256-AA (balance shaft engines) for:

-’99-’01 4×4 Explorer/Mountaineer

-’01-’02 4×4 Sport/Sport Trac

-All ’02 Explorer/Mountaineer, except engine codes 2G-960-AA and 2G-964-AA

Use kit 2U3Z-6D256-BA (non balance shaft engines) for:

-’99-’01 4×2 Explorer/Mountaineer

-’01-’02 4×2 Sport/Sport Trac

-’02 Explorer/Mountaineer with engine codes 2G-960-AA and 2G-964-AA

-All 2001-02 Ranger

Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.

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