Thread: Engine low oil light. Change it to a pressure gauge, any one done it?

I fitted a gauge to my D2 TD5 when like you the oil light came on intermittently. The problem turned out to be damaged wiring to the sender unit located behind the turbo.

LR must have got a special on wires as the black wire does Nothing/nada.

You can fit a gauge sender with a n adaptor and also have a light, but I would buy a new sender.

IMHO gauges ( and lights) are a bit of a waste of time as by the time you see a drop, the engine is toast, particularly if the oil pump bolt loosens.
Otherwise you just worry when the oil pressure looks low at idle. If the oil pressure is low on a TD5 the rest of the engine will be worn and you will see lots of other clues like excessive blowby.
Regards PhilipA

Originally Posted by PhilipA

LR must have got a special on wires as the black wire does Nothing/nada.

You can fit a gauge sender with a n adaptor and also have a light, but I would buy a new sender.

IMHO gauges ( and lights) are a bit of a waste of time as by the time you see a drop, the engine is toast, particularly if the oil pump bolt loosens.
Otherwise you just worry when the oil pressure looks low at idle. If the oil pressure is low on a TD5 the rest of the engine will be worn and you will see lots of other clues like excessive blowby.
Regards PhilipA

Thanks. With 421000 + kms I don't think it is the bolt. There is no blowby, or very little. So, do you know which wire goes to the light? It operates on voltage drop, so I'm thinking there must be a voltage input from somewhere. But there are only two sockets, and one is for the black wire.

Originally Posted by Milton477

I fitted a gauge to my D2 TD5 when like you the oil light came on intermittently. The problem turned out to be damaged wiring to the sender unit located behind the turbo.

Thanks. I seem to have a lack of wiring to the sender. Just a black wire that goes no where. Doesn't make sense.

Originally Posted by bob10

Thanks. With 421000 + kms I don't think it is the bolt. There is no blowby, or very little. So, do you know which wire goes to the light? It operates on voltage drop, so I'm thinking there must be a voltage input from somewhere. But there are only two sockets, and one is for the black wire.

From memory there’s a Black wire (goes nowhere) and a White(?) wire.

The NON-Black wire is the one that should be connected to the switch.

The switch is normally closed, opens when pressure builds, and if pressure fails then the circuit closes to ground (engine block) and the light illuminates.

I know the system works on voltage drop, but to have a voltage to start with, I assume [ there's that word again] that that wire from the alternator should be connected to the connection.

You know wrong... that's a simple pressure switch normally closed to earth which opens under pressure, while it's closed it completes the warning lamp's earth path hence the lamp is on then when pressure opens it the lamp goes out... the alternator has nothing to do with this also as PhilipA said the black wire is futile cos the switch is earthed via fixing... if you have a white(with green trace) wire hanging from the alternator you have to connect it back where it belongs cos it's the alternator's protection.

EDIT: @Tombie was faster

Originally Posted by Tombie

From memory there’s a Black wire (goes nowhere) and a White(?) wire.

The NON-Black wire is the one that should be connected to the switch.

The switch is normally closed, opens when pressure builds, and if pressure fails then the circuit closes to ground (engine block) and the light illuminates.

Thanks. Starting to make a bit of sense. Just can't find the wire that goes to the switch. There is a white wire coming from the alternator which is hanging loose , on the other sise of the engine. Oh well, looks like I have to trace it back from the light. Happy days. Cheers.

Originally Posted by bob10

Thanks. Starting to make a bit of sense. Just can't find the wire that goes to the switch. There is a white wire coming from the alternator which is hanging loose , on the other sise of the engine. Oh well, looks like I have to trace it back from the light. Happy days. Cheers.

Loom passes behind the engine above the bell housing.
Start looking from Drivers side.