Oil Pressure dropping

Hi members

So I posted back in june about my oil pressure dropping and had some good advice. The sender units have been changed along with the oil pump and different oil (was 10W 40 now 15W40)  When I start the car its at about 2.5 BAR but after about 15 mins driving the pressure drops and the light and buzzer sounds.

Think Ive tried most things to solve this? It uses no oil or smokes. Starting to do my head in now!!

Any other advice is greatly appreciated

Thanks

Dom
 

The buzzer and the light are controlled by the High RPM low pressure switch which is white on the oil filter flange.

Bad Grounds cause a variety of issues if you haven't replaced your Battery to frame and Frame to engine ground I would do so and re-test.

If you didn't change your white pressure switch on the flange I would do so as well.  If your connector is flakey as in old and green, I would replace it too.

Then run the engine with a Mechanical gauge and verify that you have an oil pressure issue.  Is the 15W40 that you are using Synth?  Synth oil thins more quickly than Dino.

I use 20W50 in my 93, and 92, but then I have the 2.0L oil pumps and I use only wix filters.

I havent replaced the eath straps but im not sure that is that,seems odd the pressure starts normal then drops off after 15 or so minutes. Ill get hold of a oil pressure test/compression kit and see if that helps and see what the readings are.
Thanks for your help