Assessment Of Cylinder Liners (Checking Crankcase): 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 behaviour 
• 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... 

Mechanical engine diagnosis: 

1. Check compression level. → 101902 CHECKING COMPRESSION OF CYLINDERS 
2. Check for loss of pressure. → 101802 TESTING PRESSURE LOSS FROM THE ENGINE 
3. If you suspect engine damage, drain the engine oil and remove the oil filter. For details of how to do this, see → WM 170117 CHANGING ENGINE OIL AND OIL FILTER ON DFI ENGINES . Check for metallic wear, breaks and similar problems.
4. If you suspect there is a problem, set the timing.
   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.

5. 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. 5.1. Remove spark plugs (if you have not already done so, or if you have re-installed them).
   2. 5.2. Turn the piston in the relevant cylinder to the bottom dead centre. 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. 5.3. 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. 5.4. Examine the cylinder liner all the way around. → 101001 ASSESSMENT OF CYLINDER LINERS (CHECKING CRANKCASE) 
6. If you discover engine damage, install a short engine (4.5-litre).