| Cause | Correction | 
      
       | Low oil pressure 
 
 | 
 
          
           
            | • | Repair or replace as required. 
 
 |  
 | 
      
       | Loose and/or worn valve rocker arm attachments 
 
 | 
 
          
           
            | • | Inspect the valve rocker arm stud, nut, or bolt. 
 
 |  
          
           
            | • | Repair or replace as required. 
 
 |  
 | 
      
       | Worn or damaged valve rocker arm 
 
 | Repair or replace as required. 
 
 | 
      
       | Improper lubrication to the valve rocker arms 
 
 | Inspect the following components and repair or replace, as required: 
 
 
 
          
           
            | • | The oil filter bypass valve 
 
 |  
          
           
            | • | The oil pump and pump screen 
 
 |  
          
           
            | • | The engine block oil galleries 
 
 |  
 | 
      
       | Broken valve spring 
 
 | Replace the valve spring. 
 
 | 
      
       | Excessive valve lash 
 
 | 
 
          
           
            | • | Inspect valve lash adjusters. 
 
 |  
 | 
      
       | Bent valve pushrod 
 
 | 
 
          
           
            | • | Inspect valve pushrod and valve rocker arm. 
 
 |  
          
           
            | • | Repair or replace as required. 
 
 |  
 | 
      
       | Worn or dirty valve lash adjusters 
 
 | Replace the valve lash adjusters. 
 
 | 
      
       | Stretched or broken timing chain and/or damaged sprocket teeth 
 
 | Replace the timing chain and sprockets. 
 
 | 
      
       | Worn, damaged, or faulty timing chain tensioners 
 
 | Replace tensioners 
 
 | 
      
       | Worn camshaft lobes 
 
 | 
 
          
           
            | • | Inspect the engine camshaft lobes. 
 
 |  
          
           
            | • | Replace the camshaft and valve lash adjusters as required. 
 
 |  
 | 
      
       | Worn valve guides or valve stems 
 
 | Inspect the following components and repair, as required: 
 
 
 
 | 
      
       | Stuck valves 
 Carbon on the valve stem or valve seat may cause the valve to stay open.
 
 
 | Inspect the following components and repair, as required: 
 
 
 
 | 
      
       | Damaged or misaligned timing gears 
 
 | 
 
          
           
            | • | Replace all damaged components. 
 
 |  
 |