Porous Wet Liner

Photograph shows classic liner corrosion associated with wet cylinder liners. This sort of damage occurs more often in engines without the correct anti-freeze mixture. Fortunately the liners can be replaced with the engine still in the machine. However, on Marshall tractors fitted with the Explorer Cab, access is tight for number 3 and particularly number 4 cylinder. The classic symptom of porous liners is loss of coolant into the engine oil causing grey/white engine oil. This particular liner was removed from a Leyland 4/98 engine. The inside of the liner is completely unworn with no top ring groove. In fact, the honing marks are still visible from when it was made. 

I've also seen liners that are completely un-corroded on the outside and worn out on the inside after 9 or 10 thousand hours work. Occasionally, the liner seals between the liner and the cylinder block can fail either due to age or over-heating giving the same water in the oil symptoms.