In 1998, because the previous generation of diesel engines didn’t meet Euro3 standards, Land Rover developed the Td5 for their Discovery Series II and Defender models.
A very sophisticated diesel engine, for its time, came with a decent number of issues and problems.
The most common problem with the Td5 engine is a failure of the head gasket, which could cascade into numerous additional issues. Caused by the insufficient production quality can be fixed relatively quickly, but it is not the only common problem.
So, if you plan to purchase a vintage diesel Disco II older than 2005 or a diesel Defender older than 2006, there are some potential issues with their engine you must be aware of. But also how they can be fixed.
Most Common Land Rover Td5 Engine Problems
Land Rover vehicles equipped with Td5 engines are well known for reliability if they are properly maintained, and many problems are detected in time.
This turbocharged 2.5 liters inline 5-pot engine was very advanced for the time when it was launched on the market.
And was a bleeding-edge unit, in the most genuine meaning of having potentially catastrophic problems.
These problems are relatively affordable to fix and, if left on their own, could lead to a complete engine failure. Some of them even can lead to the engine becoming a runaway.
So, before you buy an LR with the Td5 and it spectacularly goes on fire, let’s see the common problems and how to fix them.
Head Gasket Failure
The most common problem with the Td5 engines is head gasket failure. It would become apparent from:
- engine overheating
- white smoke from the exhaust pipe
- low coolant level
- the milky white color of engine oil
- and sometimes bubbling sound coming from the radiator and coolant reservoir
LR used plastic dowels to marry the cylinder head with the block, which would wear out and allow the head to move enough to lead to gasket failure.
If neglected, it could lead to a chipped engine bore.
The only fix is to remove the cylinder head and replace dowels with metal ones, but also pressure test cylinders and replace head bolts and gasket.
Rough Running, Bad Starting, Misfiring
Sometimes a Td5 can start to run very rough, misfire, or be relatively hard to start.
Most commonly, this is caused by the leak of the fuel injector harness. Its failed O-rings will lead to oil leaking slowly along with the harness and into the ECU, particularly near the red plug.
Fixing this is relatively straightforward, though you would have to replace the fuel injector wiring loom and O-rings and clean the ECU with 99% isopropyl alcohol on the inside.
Engine Running Uncontrollably
Under some conditions, the Td5 engine can become a runaway, starting to run uncontrollably even if you turn off the ignition.
If the engine is not forced to stall or shut down some other way, it can lead to complete and sometimes explosive destruction.
There are two most common causes of this problem, either the injector washers have failed, or the fuel rail in the cylinder head has cracked.
You can recognize any of these problems by the raised level of the engine oil and the diesel smell of the oil, as the diesel fuel is leaking into the engine sump.
This problem requires either replacement of the faulty injector washers or the cylinder head. But if not fixed soon enough, it can require a complete engine rebuild.
Squeaky Noize when The Engine Stops
On the Td5, the crankshaft pulley has a rather unorthodox construction that includes some parts made of rubber.
If you can hear a squeaking sound just as you turn off the engine, it is caused by this rubber part being worn.
Eventually, it will develop a rattling sound when idling as the torsional vibration damper bolted on the crankshaft pulley will also become damaged.
The only fix for this is to replace the crankshaft pulley and TV dampener. One thing that can go wrong with this is that the crankshaft oil seal can develop a leak needing a replacement too.
Coolant Leakage
The most common problem that leads to coolant leakage is the failure of the O-ring on the fuel cooler. And this problem can happen very suddenly by noticing the dripping of the pink OAT coolant under your car.
The end cap of the coolant line connected to the fuel cooler is sealed with an O-ring, which over time, will get completely compressed.
This is another problem with this engine that is very straightforward to fix, even though it requires some time and skill.
All you need to do is to disconnect the end cap from the cooler and remove it from the coolant hose to replace the O-ring.
Turbocharger Overboosting
If you notice that your engine is suddenly losing power for a few seconds under certain loads and RPM ranges and then gaining again, very likely that your engine is over boosting.
In this situation, the engine’s ECU reacts by cutting the fuel supply, which you can notice from the loss of power.
The cause of this is a faulty wastegate modulator that is intermittently failing to open the wastegate when needed.
The only fix for this is a replacement of the modulator because cleaning or repairing it is very complicated and almost impossible, and it is not an expensive part.
Fuel Pressure Regulator Leak
Another common problem that is caused by the relatively poor construction of a part is fuel leaking at the fuel pressure regulator.
At the driver’s side of the engine, where the fuel pressure regulator is located, you can notice a leak that can look like engine oil from the dirt around the engine bay.
To fix this, you will have to replace both the fuel pressure regulator and install a new gasket made of metal.
Conclusion
When Land Rover launched their vehicles with the new Td5 engine, it was one of the most sophisticated diesel engines on the road.
But, like any new technology, it suffered from some problems.
These were the most common ones you should be aware of and how to fix them if you plan to buy a used Discovery or Defender with this engine.
Related: 6 Common Land Rover 300Tdi Engine Problems (Explained)
Sources
https://www.kmotors.co.uk/vehicles/discovery-2/
http://www.discovery2.co.uk/Injector_harness.html
http://www.discovery2.co.uk/CrankPulley.html
