The FAQ says that oil pumps dont die - they just slowly wear out. So as they wear the oil pressure gets less and less and greatly increases engine bearing wear. It appears that oil pressure with a worn pump at 2000 rpm (city driving) and 1000 rpm (idling in traffic jam) could say be as low as say 20 psi (min specified is 36 psi), causing damage, but the oil idiot light will only go on at 7 psi for many oil pressure sensors. So the idiot light is only good for notifying of an oil "catastrophe" such as ran out of oil due to leaks, burning, etc or failed O-rings on oil delivery tube, etc.

So should high mileage non-turbo 240s (300,000 miles - 500,000 km in good condition) without a rebuilt engine be fitted with an oil pressure gauge in addition to the idiot light? (240 turbos had both these functions using the factory fitted VDO 360-009 dual-contact oil pressure sensor& gauge). I want to get 500,000 miles or 800,000 km from my 240. I've used PTFE-based anti-friction oil additive since day one.

The FAQ (and Haynes) says test your oil pressure but if you have to buy an oil pressure gauge and hose to do that then might as well permanently fit sender VDO 360-009 for US$26 and gauge VDO 350-104 for US$26?