Camshaft - Inspection
1. Inspect the camshaft journals for wear. If the journals are significantly worn, replace the camshaft.
2. Inspect the camshaft lobes for damage.
If the cam lobes are damaged or worn beyond the limit, replace the camshaft.
Camshaft lobe height [Standard] Intake: 43.4484 mm Exhaust: 43.8489 mm [Limit] Intake: 42.9484 mm Exhaust: 43.3489 mm
3. Inspect the back surface of the camshaft lobes for damage or significant wear, and replace the shaft if necessary.
4. Inspect the camshaft journal bores for damage. If the camshaft journal bore wear exceeds the allowable limit, replace the cylinder head assembly or the camshaft bearing caps.
Camshaft end play: 0.10 - 0.15 mm
CAMSHAFT OIL SEAL
1. Inspect the seal lip for wear. If the seal lip is worn, replace the oil seal.
2. Check the condition of the camshaft surface in contact with the seal lip.
If the shaft surface is worn, replace the camshaft.
HYDRAULIC LASH ADJUSTER
Hold surface "A" of the hydraulic lash adjuster filled with engine oil, and press plunger "B" by hand. If plunger "B" moves, replace the lash adjuster.
Other typical hydraulic lash adjuster malfunctions are listed in the table below.
| Malfunction | Possible Cause | Procedure |
| 1. Temporary noise when starting a cold engine | Normal condition | This noise will disappear when engine oil pressure reaches normal. |
| 2. Continuous noise when starting the engine after the vehicle has been parked for more than 48 hours. | Oil leaking from the high-pressure chamber of the hydraulic lash adjuster has allowed air to enter it. | The noise will disappear within 15 minutes when the engine runs at 2000–3000 rpm. If the noise does not disappear, refer to item 7 in the table. |
| 3. Continuous abnormal noise at initial engine start-up after cylinder head overhaul | Insufficient oil in the cylinder head oil passages. | |
| 4. Continuous abnormal noise at engine start-up after prolonged unsuccessful start attempts. | Oil leaking from the high-pressure chamber of the hydraulic lash adjuster has allowed air to enter it. Insufficient oil in the hydraulic lash adjuster. |
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| 5. Continuous abnormal noise at engine start-up after replacing the hydraulic lash adjuster. | ||
| 6. Continuous abnormal noise when the engine is idling after driving the vehicle at high speed. | Engine oil level in the oil pan is too low or too high. | Check the oil level. If necessary, drain the excess oil or add oil. |
| Excessive air in the engine oil at high crankshaft speed. | Check the lubrication system. | |
| Oil deterioration | Check the condition of the oil. If the oil has lost its properties, replace it with new oil of the correct classification, viscosity and capacity. | |
| 7. Continuous abnormal noise for more than 15 minutes. | Low oil pressure | Check the oil pressure and the lubrication system of each engine component. |
| Hydraulic lash adjuster malfunction | Remove the cylinder head cover and press the hydraulic lash adjuster by hand. If the hydraulic lash adjuster moves, replace it. |
TIMING CHAIN
Inspect the chain links (bushings and plates) for wear. Replace the chain if wear is excessive.
Test yourself
A quick Hyundai Elantra CN7 quiz: every answer comes with an explanation and a link to the manual page.