Oil warning light
Discussion
Assuming you have the AJP engine, the oil pressure warning light sensor is in the V at the back (windscreen end) of the engine, under the fuel rail. It is possible to disconnect it by reaching in from behind and ripping most of the skin off your hand. Actually removing the sensor will be far more of a challenge.
A loose wire would be more likely to cause the light to not come on at all, rather than stay on.
The gauge is completely mechanical and operated by a silver capillary tube that passes from the engine through the bulkhead, and totally independent of the warning light.
A loose wire would be more likely to cause the light to not come on at all, rather than stay on.
The gauge is completely mechanical and operated by a silver capillary tube that passes from the engine through the bulkhead, and totally independent of the warning light.
In my experience the sensors are very unreliable, I have replaced them several times and it only lasts a few months and then is broken again. I have had them fail with the light on, off and completely disintegrate causing a huge oil leak, my advice would be to ignore it and take the wire off the senior and rely on your gauge, it tells you much more about what is going on than an on/off light.
I have now disconnected mine as I have an SPA oil and water gauge which has warning lights built in.
I have now disconnected mine as I have an SPA oil and water gauge which has warning lights built in.
The oil pressure switch is a service item (costing just a fiver). I have replaced mine twice in four years, but it's never failed. However the oil pressure gauge did spring a slow leak during that time.
There is a clear advantage to having two entirely separate warning systems, so I would not recommend disconnecting one of them.
There is a clear advantage to having two entirely separate warning systems, so I would not recommend disconnecting one of them.
I believe the oil pressure switch in the "V" only needs 6lbs or more to read OK.
So, If it's working properly, and it indicates low pressure, turn off the engine!
However, the terminal on the switch is prone to short (and turn the light on) in torrential rain or after a carwash.
But the dash pressure gauge is fed independently.
If in any doubt, just turn off the engine somewhere on level ground, leave it for a half hour and then check the oil level.
So, If it's working properly, and it indicates low pressure, turn off the engine!
However, the terminal on the switch is prone to short (and turn the light on) in torrential rain or after a carwash.
But the dash pressure gauge is fed independently.
If in any doubt, just turn off the engine somewhere on level ground, leave it for a half hour and then check the oil level.
Changed OP sensor a few months ago and the part number in the parts sticky was not correct. I ended up getting the new oil pressure switch from Bespoke in Ware. The thread size and width were different. I have a 4.5 so should be the same? You can look at my thread to see the difference. My OP sensor was actually flashing with the engine revs.
Little bit of a pain as difficult access. You would need very small hands to get in there otherwise.
Little bit of a pain as difficult access. You would need very small hands to get in there otherwise.
gruffalo said:
In my experience the sensors are very unreliable, I have replaced them several times and it only lasts a few months and then is broken again. I have had them fail with the light on, off and completely disintegrate causing a huge oil leak, my advice would be to ignore it and take the wire off the senior and rely on your gauge, it tells you much more about what is going on than an on/off light.
And on the other side, after driving the Cerb 50000 miles, i've never replaced one 
TheRainMaker said:
gruffalo said:
In my experience the sensors are very unreliable, I have replaced them several times and it only lasts a few months and then is broken again. I have had them fail with the light on, off and completely disintegrate causing a huge oil leak, my advice would be to ignore it and take the wire off the senior and rely on your gauge, it tells you much more about what is going on than an on/off light.
And on the other side, after driving the Cerb 50000 miles, i've never replaced one The one that turned into an oil fountain happened on the way to Le Mans so it became a bolt to blank the whole and has remained like that for a good few years now.
The gauge is what is important in my opinion, if you are driving with oil pressure low enough to make the light come on then the damage has already been done and it is rebuilt time, if there was a sensor that gave an early warning at say 20PSI I would hold more truck with that and probably fit one, that is where I have the oil light on my SPA gauge programmed at to trigger the alarm.
We are also fortunate that the AJP does not typically suffer from problems that cause low oil pressure, they are actually quite a tough lump.
Edited by gruffalo on Thursday 21st April 07:33
Edited by gruffalo on Thursday 21st April 09:05
All this talk of sensors failing I find hard to believe! My own experience is that the one that is on the car was on there before I had the vehicle. I have since driven over 20k miles and it still works. AFAIK it has never been replaced as I don't remember seeing a replacement part in the history anywhere. Perhaps there was a terrible batch of these!
J
J
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