2495cc diesel, overhead valve: Land Rover reworked the old 'two and a quarter' diesel for the Eighties. The injection pump was now driven off a toothed belt at the front of the engine (together with the camshaft) which sorted the pump timing drift problem of the older diesels, and the increase in capacity provided a bit more power. Slow but strong, simple and dependable, this engine remains rightly popular.
2495cc turbodiesel, overhead valve, type 19J: Given the strength and reliability of the 2.5 diesel, you can understand why Land Rover thought it would cope with turbocharging, but the result was a warranty nightmare. 2.5TDs can fail in any number of ways, but the most common seems to be internal cracks developing in the cylinder block. This gives the same symptoms as a blown head gasket or cracked cylinder head, but is not repairable. Due to a defective design of crankcase breather, these engines also tend to dump large amounts of engine oil into the air filter housing, which turns the paper air filter into a soggy black lump. This in turn leads to oil being drawn into the air intake, causing the engine to 'run away' and self-destruct.
Land Rover introduced a new cylinder block for the 2.5 Turbodiesel (part no. ERR479) from engine number 19J27515C. I have not been able to confirm, but suspect that this block was strengthened to get round the block cracking problems I would consider rebuilding a later engine, but not one of the earlier ones. In general, if the vehicle itself is any good, the sensible thing to do is to upgrade to a 200TDi (see below), or for old and tatty TDs the 2495cc non-turbo engine is a very straightforward swap, with only the air intake hose and exhaust system needing to be changed.
2495cc turbodiesel, overhead valve, 200TDi and 300TDi: Second time lucky for Land Rover. The lessons learned from the 2.5TD were incorporated into the new TDi engines available in the Defender and Discovery from 1990. The cylinder block still looked familiar (although strengthened internally with an aluminium ladder frame bolted to the bearing caps) but the cylinder head was all-new and a direct injection fuel system was used. These engines have gained an impressive reputation for power and durability. Defender engines produced 107bhp, Discovery engines (with different manifolding and a couple of other small changes) 111bhp. The 300TDi has a single serpentine drive belt for alternator, power steering etc, better soundproofing and a few small internal differences compare to the 200TDi. Power outputs of the two engines are identical. Though no longer offered in Europe (due to emissions regulations) the 300TDi remains available in some export markets.
2495cc turbodiesel, 5 cylinder, TD5: New and much stricter Euro emissions regulations for diesel engines led Land Rover to develop an all-new engine for the second generation Discovery, and this also found its way into the Defender. The TD5 features electronic control of the fuel injection system (with a control unit under the driver's seat), 'drive by wire' throttle and other refinements, all aimed at minimising exhaust emissions. Early reaction was mixed: the TD5 was much easier to stall than the earlier diesel engines (a characteristic shared by many of the latest generation of environment-friendly diesels) and there were reports of oil pump failures, cylinder head problems and other reliability issues - but not on anything like the scale of the 2.5TD fiasco in the Eighties. In any case, these issues appear to have been resolved, and the TD5 has turned out to be a lovely engine - much smoother than the old TDi, and it sounds better too.
