The procedure to check if the cassette is damaged does not require the removal of the engine. The engine also does not require removal if the only cassette they are replacing is the front one. The radiator as well as the front engine cover need to be removed, but not the engine. Here is the procedure to verify if the cassette is bad:
Inspection
1. Is engine running?
^ Yes, continue to step 2.
^ No, go to step 6.
2. Check the engine oil level before performing the inspection. Add oil, if necessary.
3. NOTE : The engine should be cold.
Start engine and listen for excessive cam chain noise at the front (left) cam chain.
Also, observe the motor to determine if it is running smooth or rough at idle.
^ If noise goes away within five minutes, check OASIS and perform 00M12 if appropriate.
^ If noise persists, continue with the inspection procedure.
VEHICLES WITH ENGINE RUNNING SMOOTH
4. Remove the left and right valve cover. Refer to Valve Covers in Section 303-01B in the appropriate Workshop Manual.
5. Inspect the left cam, right cam and upper valve train for damage caused by lack of lubrication.
^ If there is damage to the cam(s) or valve train, contact the Special Service Support Center at 1-800-325-5621.
^ If the cams and valve train are not damaged, perform CAMSHAFT CASSETTE REPLACEMENT.
ENGINE RUNNING ROUGH (OR NOT RUNNING)
6. Remove the left valve cover. Refer to Valve Covers in Section 303-01B in the appropriate Workshop Manual.
7. Inspect the left cam and upper valve train for damage caused by lack of lubrication.
^ If there is damage to the cam or valve train, contact the Special Service Support Center at 1-800-325-5621.
^ If the cam and valve train are not damaged, continue with the inspection procedure.
8. Perform a cylinder leakage test on the left cylinder bank as follows.
A. Remove the camshaft roller followers from the left side of the engine. Refer to Roller Followers in Section 303-01B in the appropriate Workshop Manual.
B. Remove the spark plugs from the left side of the engine.
C. For each cylinder, install the Rotunda Engine Cylinder Leak Detector/Air Pressurization kit, 014-00708 or equivalent, into the spark plug hole.
D. NOTE: Since the cam followers have been removed, all the valves on the left cylinder bank will be closed. Therefore, it is not necessary to bring the pistons to top dead center during the leakdown test.
Pressurize each cylinder with compressed air and read the cylinder leakage gauge.
^ If any cylinder has a reading in excess of 50 percent, contact the Special Service Support Center at 1-800-325-5621.
^ If all of the cylinders have a reading of 50 percent or less, continue with the inspection procedure.
9. Remove the right valve cover. Refer to Valve Covers in Section 303-01B in the appropriate Workshop Manual.
10. Inspect the right cam and upper valve train for damage caused by lack of lubrication.
^ If there is damage to the cam or valve train, contact the Special Service Support Center at 1-800-325-5621.
^ If the cam and valve train are not damaged, perform CAMSHAFT CASSETTE REPLACEMENT.