Service Procedure
1. Drain the engine oil, replace the oil filter with a Genuine Isuzu oil filter, and refill the crankcase with 0W-30 Mobil 1 synthetic engine oil.2. With the engine warm, run it at 2,500 rpm for 30 minutes.
^ If the ticking noise goes away, return the vehicle to the customer.
^ If the ticking noise persists, proceed with step 3.
3. Let the motor run at idle and use a stethoscope or Steel screwdriver to determine which bank is noisy. Once you have determined the location, turn the key off. (Figure 1)
4. Remove the cylinder head cover on the noisy bank.
5. Inspect each rocker arm for clearance at the valve (when the rocker is on the base circle of the cam and the valve is closed). The noisy rocker arms are the ones with clearance. (Figure 2)
NOTE:
Each cylinder head has one oil pressure relief valve that controls oil pressure to its rocker arms. If all rocker arms on one cylinder head have clearance and/or the rocker arm pivot shaft is worn, then the cylinder head oil pressure relief valve may be stuck open. In this case, refer to the appropriate Workshop Manual for additional troubleshooting procedures.
6. Remove the ticking rocker arm assembly, and inspect the wear pattern of the hydraulic lash adjuster surface that contacts the valve stem (the intake rocker arm is located under the camshafts, which require timing belt removal).
7. Carefully remove the Hydraulic Lash Adjuster(s) from the Rocker Arms using your fingers. (Figure 4)
IMPORTANT:
Do not damage the O-Ring on the outside of the Hydraulic Lash Adjuster, or you will have to replace the entire rocker arm (the Hydraulic Lash Adjuster cannot be ordered separately). When replacing an exhaust rocker arm, replace its intermediate rocker arm too.
8. Insert a paper clip into the hole at the top of the Hydraulic Lash Adjuster and depress the spring loaded check ball, while completely pushing in the piston at the opposite end. Some traces of oil may come out of the check ball hole. (Figure 5)
9. Carefully remove and retain the Hydraulic Lash Adjuster O-Ring. Spray the Hydraulic Lash Adjuster piston with carburetor cleaner to remove any varnish (while holding the piston in). (Figure 6)
10. Submerge the Hydraulic Lash Adjuster in new cleaning solvent; (while depressing the check ball) pump the piston repeatedly to allow the cleaning solvent to penetrate through the Hydraulic Lash Adjuster. (Figure 7)
11. Submerge the Hydraulic Lash Adjuster in clean 0W-30 Mobil 1 synthetic engine oil, (while depressing the check ball) pump the piston repeatedly to allow 0W-30 Mobil 1 synthetic engine oil to penetrate through the Hydraulic Lash Adjuster. Then allow the piston to extend fully, to fill the Hydraulic Lash Adjuster with oil.
12. Reinstall the Hydraulic Lash Adjuster O-Ring.
13. Lube the Rocker Arm bore that houses the Hydraulic Lash Adjuster with 0W-30 Mobil 1 synthetic engine oil, then push the Hydraulic Lash Adjuster back into place.
14. Inspect for leaks at the check ball and piston by attempting to compress the Hydraulic Lash Adjuster without depressing the check ball (The Hydraulic Lash Adjuster should not leak or compress).
NOTE:
Oil filled Hydraulic Lash Adjuster will hold its valve off the seat for several crank revolutions. This may cause the engine to run rough for a short period after starting. To prevent this, select one cylinder and bleed some oil off the Hydraulic Lash Adjuster (depress the Check Ball and compress the piston 1/4 of the way down). This will allow the valve to close. Do not remove all of the oil or the valves spring and cam will collapse the Hydraulic Lash Adjuster permanently.
15. Reassemble the engine using new cylinder head cover gasket (see Parts Information) and apply some gasket seal at the corners where the cam tower gasket and cylinder meet. Torque the Cylinder head cover bolts to 8 Nm (69 lb. in) using hand tools only.
16. Start the engine and listen for noise.
17. Remind the customer, "More frequent oil changes can prevent varnish accumulation." Also recommend to use minimum oil rating of: API Service SG, but SJ is preferred.