Cylinder Liner: Service and Repair
Assessment of cylinder liners (checking crankcase)
Assessment of cylinder liners (checking crankcase)
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 sources of noise
Strong rattling and clicking noise when the engine is idling
Mechanical noises 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...
Mechanical engine diagnosis:
1. Check compression level.
2. Check for loss of pressure.
3. If you suspect engine damage, drain the engine oil and remove the oil filter. Check for metallic wear, breaks and similar problems.
4. If you suspect there is a problem, set the timing.
Notice:
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.
5.1. Remove spark plugs (if you have not already done so, or if you have re-installed them).
5.2. 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.
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.
5.4. Examine the cylinder liner all the way around.
6. If you discover engine damage, install a short engine (4.5-liter).
Signs of damage to cylinder liners in the endoscope
Ideal condition of used cylinder! - Continued use acceptable! The typical fine-marking that develops at a very early stage is apparent. The liners are a yellow-brown color with a slight speckled effect in places. The liner keeps its silver color in places with more intense lateral force transmission.
Perfect cylinder liner
Ideal condition of used cylinder! - Continued use acceptable! The typical fine-scoring that develops at a very early stage is apparent. The liners are a yellow-brown color with a slight speckled effect in places. The liner keeps its silver color in places with more intense lateral force transmission. Minor visible marks can be ignored. -arrow-
Ideal condition of used engine
Ideal condition of used cylinder! - Continued use acceptable! (4 illustrations) A typical polished cylinder liner, which develops at an early stage, is evident. The liners have several polished, shiny silver areas. The liner retains its silver color in areas subject to higher lateral force transmission. Minor visible marks can be ignored.
Ideal condition of used engine with polished running tracks 1
Ideal condition of used engine with polished running tracks 2
Ideal condition of used engine with polished running tracks 3
Ideal condition of used engine with polished running tracks 4
Damaged cylinder liner! - Engine damage! Extensive areas of deeper scoring are apparent in this state -arrows-.
Damaged cylinder liner with deep scoring
Damaged cylinder liner! - Engine damage! Liner damage, piston seizure. Signs of this type of damage include knocking noises due to inadequate piston guidance in the cylinder, rough idling, blue smoke, the Check Engine light may come on. Negative pressure loss test.
Piston seizure