Assessment Of Cylinder Liners: Notes

Information 

The symptoms of cylinder liner damage and in the worst case scenario, piston seizure, are generally rather inconspicuous. At an advanced stage, the most common symptoms include the following:

• Blue smoke in the exhaust gas (burned engine oil); rule out alternative causes (leaking turbocharger, leaking valve-stem seals, etc.) 
• Piston knocking when the engine is cold (inadequate piston control in the cylinder); rule out alternative causes and noise sources 
• Strong rattling and clicking noise when the engine is idling 
• Mechanical noise during acceleration 
• High engine oil consumption 
• Check Engine light comes on when engine oil level is low 
• Loss of power 
• Rough idling 
• Bad cold-start behavior 
• and so on... 

Information 

Rule out the following components and component groups as alternative causes of cylinder liner damage:

• Read out DME fault memory and correct faults. 
• The ignition system must be in perfect condition. 
• The fuel system (fuel injection system) must be in perfect condition. 
• The intake system must be leak-free and in perfect condition. 
• On turbo engines, the turbochargers must be leak-free and in perfect condition. 
• Auxiliary units, such as the generator, air-conditioning compressor and power-steering pump must be in perfect condition. Replace defective and loud auxiliary units. 
• and so on... 

Information 

General procedure for documenting suspected problems:

• Do not erase the fault memory! 
• Create vehicle analysis log (VAL)  .
• Perform acoustic assessment -> create a sound file. 

Possible causes of noise: Timing chain, timing chain tensioner, tappets, camshafts, camshaft controllers...

General running noise check using a stethoscope (e.g. Hazet tool) to narrow down the source of the noise.

• Oil pressure measurement -> measurement log 
• Check condition of spark plugs 

Description: e.g.: white, sooty, wet. Component assignment: This may be helpful in pinpointing the individual cylinder.

• Perform compression test 
• Check for loss of pressure 
• Check liner using endoscope -> pictures + brief description 
• Condition of oil (chips, particles) -> pictures 
• Additional data, such as mileage, oil consumption that may have been determined 
• TCC approval is required for vehicles in the F&S process 

Mechanical engine diagnosis: 

1. Check compression level. → 101902 CHECKING COMPRESSION OF CYLINDERS 
2. Check for loss of pressure. → 101802 CHECKING FOR LOSS OF PRESSURE 
   NOTE: Turning the crankshaft

   • Risk of irreparable damage to endoscope

   → Disconnect the battery and make sure the vehicle cannot start.

   → Pull the endoscope out of the spark plug recess before turning the crankshaft with your hand.

   → Only observe a downward-moving piston using the endoscope.

3. Light up conspicuous, suspect cylinders with the endoscope and examine them. Use Storz endoscopes for Porsche vehicles WE 1057  or a similar endoscope for this.
   1. 3.1. Remove spark plugs. → 287020 REMOVING AND INSTALLING SPARK PLUGS
   2. 3.2. Turn the piston in the relevant cylinder to the bottom dead center. To do this, turn the crankshaft clockwise at the vibration balancer until the piston crown is positioned as far down as possible when viewed through the endoscope.
   3. 3.3. Adjust the endoscope to its brightest setting and have a good look all around the cylinder liner. You can also shine a torch into the spark plug recess to help you check for damage.
   4. 3.4. Examine the cylinder liner all the way around.