OEM Chevrolet Trailblazer Timing Chain

Chevrolet Trailblazer Timing Chain Parts and Q&A

• Timing Chain
  12571725
  Q: What tools are required to replace the timing chain, sprockets, or tensioner on Chevrolet Trailblazer?

  A:

  To replace the Timing Chain, sprockets, or tensioner, the following tools are required: torque angle meter (J 36660-A) and camshaft holding tool (J 44221). The first step involves removing both the camshaft cover and the engine front cover. Move the tensioner shoe so the tension on the Timing Chain resolves then install a tee device to secure the shoe position. Start by removing the top chain guide bolts then the top chain guide before continuing with the exhaust camshaft position actuator bolt and actuator and the intake camshaft sprocket bolt and sprocket followed by Timing Chain and crankshaft sprocket. Begin by removing the cylinder head access hole plugs before moving on to extract the Timing Chain Tensioner shoe bolt and tensioner shoe and then proceeding to remove the Timing Chain Tensioner guide bolts and guide before finishing with the Timing Chain Tensioner bolts and the tensioner itself. For installation, secure the Timing Chain Tensioner with bolts and tighten to 25 nm (18 ft. Lbs.), then install and secure the Timing Chain Tensioner guide with bolts tightened to 10 nm (89 inch lbs.)the installation begins with securing the Timing Chain Tensioner shoe bolt then tightening it to 26 nm (19 ft. Lbs.). Fit cylinder head access hole plugs before tightening them to 5 nm (44 inch lbs.). Use the camshaft holding tool (J 44221) placing the camshaft flats up alongside the number 1 cylinder at top dead center before installing the crankshaft sprocket and intake camshaft sprocket into the Timing Chain with dark link alignment to the intake camshaft sprocket timing mark. Set the Timing Chain to flow through the head opening and fix it to the crankshaft sprocket while keeping the dark link in line with the timing mark. When rotating the camshaft (hex) with the holding tool (J 44221) you should remove it before positioning the camshaft correctly. Fix the intake camshaft sprocket onto its respective camshaft before adding the intake camshaft sprocket washer and securing the bolt. Begin placing the exhaust camshaft actuator inside the Timing Chain with dark link alignment to the exhaust camshaft actuator timing mark position. Alignment requires removing the camshaft holding tool (J 44221) occasionally. Install the exhaust camshaft actuator onto the exhaust camshaft by rotating it clockwise relative to the camshaft immediately before securing the bolt. Advance the camshaft actuator by rotating it clockwise until it reaches its stopping point to avoid engine damage during installation. Tighten the exhaust camshaft actuator bolt to 25 nm (18 ft. Lbs.) first tighten the bolt to 25 nm (18 Ft. Lbs.) using hand torque then finish the tightening process with torque angle meter (J 36660-A) to achieve 135°. Tighten the intake camshaft sprocket bolt to 20 nm (15 ft. Lbs.) apply an initial torque setting of 25 nm (18 ft. Lbs.) with the torque angle meter (J 36660-A) for the second stage to achieve a 135° total rotation. The camshaft holding tool (J 44221) should be removed after removing the tee from the Timing Chain Tensioner to reestablish Timing Chain tension. Handle the Timing Chain carefully so the dark lines match the sprocket marks before installing the top chain guide then apply threadlock gm p/n 12345496 to top chain guide bolt threads and install bolts with 10 nm (89 ft. Lbs.) torque. To complete the installation you should place the engine front cover and the camshaft cover in position.