GM 12686787 ADJUSTER ASM-HYD VLV LASH

A noisy lash adjuster can be isolated while the engine is idling by using a mechanic's stethoscope or a length of hose near each valve, listening at the other end, or by removing the valve cover and touching each valve spring retainer one at a time to feel for shock if a adjuster is defective. Common causes of noisy adjusters include dirt trapped inside and insufficient oil, so it's important to check the oil for fuel contamination, level, cleanliness, and viscosity before making any judgments. To remove the adjusters, first take off the valve cover and lower intake manifold, then remove the rocker arms and pushrods. Next, take out the bolts holding the roller adjuster guides to the block and remove the guides, marking them for reinstallation. Adjusters can be extracted using a special tool, a small magnet, or a machinist's scribe, but caution is advised against using pliers unless replacing the adjusters, as they may cause damage. Store the adjusters in a labeled box to ensure they are reinstalled in their original locations. Since parts for lash adjusters are not sold separately, cleaning them is often more practical than replacement. Thoroughly clean and dry the adjusters, checking for scuffing, score marks, or uneven wear, and inspect the rollers for wear or damage. When reinstalling used adjusters, ensure they go back into their original bores, soak new adjusters in oil, and coat all adjusters with moly-base grease or engine assembly lube before installation. Finally, install the adjusters and guides, tighten the bolts to the specified torque, and run the engine to check for oil leaks.

The removal of it turns out to be complicated and special tools are needed, new camshaft sprocket bolts, which you should probably buy every time. There are three special implements required to hold the timing chain relative to the cylinder head on the intake and the exhaust side. Then the pressure of the fuel system must be released and the negative terminal of the battery must be disconnected whereas the air filter housing, the ignition coils, the spark plugs, and the valve cover should be unbolted. The timing chain tensioner is then removed, the crankshaft is turned in order to place the special tool that will loosen the camshaft actuator bolts in place. All actuators are tagged for the re assembly and the upper chain guide is also taken off. Other tools are used to secure the timing chain before the removal of camshaft actuators and camshaft solenoids. Camshaft cap is identified by its location and orientation; the camshafts are lifted off the cylinder head but all the related accessories have to remain neat. The hydraulic lash adjusters are located on the heads or issuces of their respective rockers and properly storrage with the rockers. Lash adjusters, for example, are checked for wear or damage, and the measurements of the rocker arms as well as camshaft lobes are gone through to meet a specified gauge. Any elements, which are recognized as worn beyond their acceptable limit, have to be replaced. There is also the lubrication of the rocker arms and the lash adjusters, correct setting of the camshafts and the final tightening of the bearing caps as per a set sequence. Camshaft sprocket actuators and timing chain are put in position and screwed then timing chain tensioner is reprogrammed. Last of all, the upper timing chain guide is bolted and tightened and the battery connection is restored and the process is then done.

This operation is a somewhat complicated one, and it employs instruments that are specific to it, so make sure you read through all the directions and make sure you have all the tools you will need ready before beginning the operation. On the first step, you must unplug the cable from the negative terminal on the battery, and on the second step, take off the valve cover. Place the engine at TDC of cylinder number one and rotate the crankshaft in anti-clockwise direction to position the crankshaft at 60 degrees before TDC, while positioning the diameter shaped hole at twelve o clock position on intake camshaft. Secondly, take off the upper timing chain guide and place a particular tool that will immobilise the camshaft sprockets. Remove the bolts on the camshaft sprocket and put the sprockets aside, in addition, loosen the wing nuts that lock the sprockets in place. Another feature is that each camshaft cap features a number, which shows the position of the camshaft; each bearing cap bolt should be loosened gradually but firmly enough to lift the camshaft from the cylinder head. Take out the rocker arms while in so doing retain them and the hydraulic lash adjusters so that they can be refitted. Remove the exhaust bearing caps followed by the rocker arms and the lash adjusters in like manner. Each hydraulic lash adjuster needs to be checked for wear and each of them needs to have its diameters measured; if the lash adjusters are out of round, they will have to be exchanged. Inspect the rocker arms for any signs of wear or damage, the camshaft lobes also for wear, the thickness of the lobe and if there is a massive variation replace the camshaft. Check the camshaft bearing journals for wear and measure the diameter of each; replace any that do not conform to minimum size. To check the bearing journal oil clearance, all the bearing surfaces must be cleaned, followed by installing the camshafts together with the bearing caps with Plastigage across the journal, and as the bolts are tightened, the width of the flattened Plastigage is then to be measured. If any oil clearance is over the service limit, then the camshaft, or the cylinder head should be replaced. On camshaft end play, the bearing surfaces must be cleaned and the camshafts and bearing caps put in place before using a dial indicator to check on the end play. If the endplay is at any time beyond the service limit, it is advisable to replace either the camshaft thrust cap or the camshaft. For assembly, apply oil to the rocker arms and the lash adjusters and then position them as earlier used. Oil the camshafts and then place it properly and follow through the camshaft bearing s which have to be tighten in sequence. Move the camshaft sprockets and the timing chain right to the camshafts, so that the slots get into the corresponding projections on the sprockets and screw new bolts. Take out the camshaft locking tool, screw and tighten the front and rear camshaft cap to the recommended torque. The upper timing chain guide must be fitted, and the engine has to be rotated by hand in order to feel the level of the resistance. Finally, reconnect the battery.

They must be returned to their original position on the engine.

Disconnect the cable from the negative battery terminal.

Inspect the rollers for binding and roughness; if the bearings are worn or damaged, replacement of the entire rocker arm will be necessary.

Remove the bolts and camshaft retainer plate, noting the orientation. Thread three long bolts into the camshaft sprocket bolt holes to assist in removal. Carefully pull the camshaft out, supporting it near the block to prevent damage to the bearings.

The hydraulic lash adjusters can be lifted from the cylinder head, ensuring that any reused components are placed back in their original positions.

If the lifters are stuck due to gum and varnish buildup, they can be extracted using a special tool or, in some cases, a small magnet or fingers.

For these engines, remove the upper timing chain guide and use a special tool to secure the camshaft sprockets in place. Remove the camshaft sprocket bolts and slide the camshaft sprockets forward, securing them with wingnuts. If working on 2009 and later models, remove the camshaft position actuators; for 2008 and earlier models, remove the timing chain tensioner.

Remove the holding fixture, place the sprockets onto the camshafts, and tighten the bolts to the specified torque.

Lubricate the camshaft bearing journals and lobes, then slide the camshaft into the engine, supporting it near the block. Turn the camshaft until the dowel pin is in the 3 o'clock position, install the camshaft thrust plate, and tighten the bolts to the specified torque.

Begin by disconnecting the negative battery terminal and removing the valve cover.

The installation process involves lubricating the rocker arms and lash adjusters, positioning the camshafts correctly, and tightening the bearing caps in a specific sequence.

Ensure that the oil passage hole in each hydraulic lash adjuster is clear.

If the adjusters or the cylinder head bores are excessively worn, new adjusters or a new cylinder head, or both, may be required.

Perform two manual engine revolutions, checking for resistance. Complete the remaining installation steps, reconnect the battery, and proceed with engine operation.

Remove the bolts and the camshaft retainer plate, noting which direction faces the block.

It is crucial to ensure proper functioning and to avoid issues related to misalignment.

The entire rocker arm will need to be replaced.

Finally, reinstall the spark plugs and the valve cover.

After removing the cam sprocket, do not rotate the crankshaft to avoid incorrect timing and potential engine damage.

Remove the lifter retainers and lifters, taking care to keep them clean. Each retainer houses four individual lifters that must be returned to their original locations if reused.

The removal process involves removing the valve covers and camshafts, then removing the rockers and lash adjuster socket on the rocker.

Remove the camshaft sprocket bolts and slide the camshaft sprockets forward, tightening the wingnuts to hold them securely.

A noisy valve lifter can be isolated when the engine is idling by using a mechanic's stethoscope or a length of hose near each valve while listening at the other end. Alternatively, you can remove the valve cover and touch each valve spring retainer with the engine idling to feel for shock if a lifter is defective.

Mark each rocker arm to ensure they are returned to their original positions, then lift them from the engine.

For 2.0L, 2.4L, and 2009 and later 2.2L engines, reinstall the camshaft actuators aligned with the marked positions and secure them with new bolts, tightening while holding each camshaft. Remove the camshaft locking tool and install the front and rear camshaft caps, torquing them to specifications. Install the upper timing chain guide and reset and install the timing chain tensioner.

Apply anaerobic sealant between the camshaft cap and cylinder head on the front caps.

Note the designation of the camshaft bearing caps on both the front and rear cylinder heads, making sure to document their locations for reassembly.

Start by disconnecting the cable from the negative battery terminal and setting the engine to 60-degrees before TDC.

Remove the camshaft sprocket bolts and slide the camshaft sprockets forward.

Remove the rocker arms and hydraulic lash adjusters from the intake camshaft.

To remove the lifters, first take off the valve cover and lower intake manifold. Then, remove the rocker arms and pushrods. Next, take out the bolts holding the roller lifter guides to the block and remove the guides, marking them for reinstallation.