Many head gasket failures have been reported on the Freelander engine on the vehicle and it has been determined that this has been commonly caused by a condition where a cylinder sleeve (or sleeves) has "dropped" in the engine block (meaning that the top of the sleeve has moved below flush with the head gasket surface of the block). The condition occurred often enough that Land Rover issued a bulletin (Technical Bulletin #0036, dated June 16, 2004) for it's dealership technicians to provide a process for inspection and evaluation when a vehicle came in for repair. Though this bulletin also addresses an overheat condition diagnosis and repair, engine overheating often accompanies head gasket failure. The head gasket would have failed primarily because the tension of the crushed compression seal ring would be compromised as the sleeve moved lower into the block and away from the cylinder head, ultimately allowing coolant intrusion into the combustion chamber and combustion gases into the cooling system. This loss of tension against a cylinder sleeve would also compromise the sealing effectiveness of the aforementioned machined surfaces of the sleeve and cylinder block and allow coolant intrusion into the crankcase and engine oil, and thus causing catastrophic engine failure as the lubricating qualities of the engine oil are severely diminished when antifreeze coolant is mixed with it.
This would explain another common concern with the Freelander engine where the engines have seized (locked up), often times while driving. The reason that the sleeves drop in the block seems to be apparent and easy to understand. There are two basic principles at work in this issue. First, there is a significant difference in the thermal properties of steel and aluminum, and second, the steel cylinder sleeves are substantially harder than the alloy aluminum cylinder block they are fitted to. Aluminum expands and contracts at a greater rate and degree than steel when heated and cooled. In the normal life of an automotive engine there are an incredible number of these heating and cooling cycles- ie: cold start up to normal operating temperature and then cool down when shut off, occasional high work loads from trailer towing, climbing long grades in extreme weather conditions, etc.
After enough of these cycles, the precision machined surfaces of the relatively soft aluminum cylinder block that relate to the fitment of the much harder steel sleeve would understandably be compromised as the aluminum is moving quicker and more than the steel in the process of thermal expansion and contraction. Add to this the fact that as the engine is running, pistons are moving up and down within the sleeves at a high rate of speed with some friction (normal-from the way that they are designed to fit within the sleeve), pushing up on the sleeve as the piston rises and then pulling down on the sleeve as the piston descends. This can effectively cause the hard steel sleeve to "hammer" against the machined surfaces within the bores of the softer aluminum cylinder block. Theses actions could be expected to cause the machined surfaces within the block to deteriorate and/or damaged to a point of failure. This helps to explain why the sleeves drop in the cylinder block, causing head gasket failure and even catastrophic engine failure. If this occurs in traffic, mechanical features such power braking will not function. Stopping and maneuvering the vehicle particularly in traffic become a serious problem, and the condition poses dangers to the driver, occupants, and other vehicles.
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