So having ruled out that the lamp itself was at fault, it could only mean one thing - the oil pressure switch on the oil pump was faulty.
It takes about 5 minutes to change, and this is how you do it.
What is an oil pressure switch?
The oil pressure switch indicates that the oil pump is producing enough oil pressure - therefore keeping the engine well lubricated.
The oil pressure light comes on when you switch the ignition on, and should go out as soon as the engine is started. The oil pressure light on a Land Rover Defender looks like the photo on the right. Discoverys and Range Rovers have a similar "oil can" symbol.
In the event of low oil pressure, the switch will activate and the light will appear on the dashboard to indicate low oil pressure. You should turn the engine off immediately if you see the "oil can" symbol light up on your dash board. Failure to do so will seriously damage your engine!
Changing the oil pressure switch on a Land Rover Tdi engine
The switch itself costs about £4, and changing the switch is the same for all 200tdi and 300tdi engines in the Land Rover Defender, Discovery and Range Rover.
You need the following tools for the job:
- Adjustable spanner
- Small container to catch some oil
- Old rag to clear up any oil
Note: Its worth checking the light bulb in the dash first, in case its as simple as a blown bulb!
1: The easiest way to get access to the switch is from under the vehicle. So the first thing to do is chock the wheels to make sure it doesn't move anywhere.
3: Pull off the wire from the switch and then use the adjustable spanner to unscrew the oil pressure switch.
4: Get your little container ready to catch the small amount of oil that will leak out after you remove the switch.
5: Screw the new oil pressure switch into place, and tighten it up.
7: Wipe up any oil that has spilt onto the surrounding components or drive train.
8: Check the oil pressure light is now working when you switch the ignition on.
That's all there is to it!