In most engines, the oil pressure warning lights works in conjunction with the pressure gauge both of which detects the oil pressure circulating inside the engine. The pressure is brought about buy an oil pump which drives the oil around. Therefore, the light going on and/or the gauge reading zero indicates that either:
1. there is very little or no oil inside the engine; or
2. the oil pump is not working.
Another possibility is that the oil is too thick for the pump to work on.
All of the above has to be corrected prior to turning your engine.
It would be very rare for both the oil pressure sensor (that activates the light) and the oil pressure gauge to be defective simultaneously.
To my understanding, most if not all Rover V8 engines have an external/mechanical oil pump that is mounted on the front
cover, the base of which carries the oil pressure relief valve and oil
filter. This pag
e has information about Rover's oil pump.
Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.
Good luck and kind regards.
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