This will be more for people that might be having a similar issue, and what it took to fix my Discovery.
A little back ground first, 99 Disco 1, 4.6 swapped in about 5,000 miles ago. I was not having any issues after the swap until about 4,000 miles ago, I had driven out about 20 miles and parked on the side of the road with some road crown putting the passenger side of the vehicle down a little bit. Left it parked for about 2 hours, came back and started it up and noticed that the oil pressure warning light was staying on much longer. I rolled the window down to listen to the engine before I drove away and could hear that it was obviously not getting pressure, so it was something much more urgent than just a faulty sensor/wiring. I shut off the engine and checked the oil level it was ok, restarted it, light stayed on again for about 45 seconds and then finally went out and I could hear that the top of the motor finally got oil to it. So I carefully drove home, no problems on the drive home. Left it in my flat driveway for a few hours, went out to start it up and the light went out within 2-3 seconds just like it always has. Curious but relieved that I wasn't starving my new engine for oil, I drove it as I normally would. A few days later I had to park on the street overnight, when I started it up the next morning the oil light was on again and not going out. I shut the car off and started thinking about when I had seen the light come on and how the car was parked, which was both times with the passenger side of the vehicle downhill slightly. So I started it up and quickly pulled into my driveway, shut it off again, and let it sit for about a minute and restarted it and the light went out within 2-3 seconds.
So I started watching it over the next week or so and could consistently duplicate the issue by parking it with the passenger side downhill and letting it sit for 2 hours or so. I got an oil pressure gauge hooked up to confirm my suspicion that the engine was loosing its prime with sitting on an angle. I could then also see if I was getting proper oil pressures when it was running (which I was). I also started playing around with parking it drivers side down to see if it mattered which side was down and it did matter, it would only act up when the passenger side was downhill.
So I took the oil pressure relief valve out and cleaned it, although it wasn't dirty or terribly tarnished. But it made no change. I again verified the correct oil level. I sat around and scratched my head for a while and finally called a good friend that is also a Land Rover master tech. His first suggestion was to replace the Bosch oil filter I had on it for a factory Land Rover filter, because the factory filters have an anti-bleed back valve in them.
Well after 3 days of driving and parking with the passenger side downhill, the oil pressure gauge has confirmed that the bosch filter was the source of my frustrations. No longer does the engine take so long to build pressure, it will build up pressure withing 2-3 seconds whether its parked on an angle or flat ground.
SO, after much worry and stress it was as simple as an oil filter. Not saying that this will fix your problem, but its simple to try and cheap. And I wish I tried it first :smilelol:
A little back ground first, 99 Disco 1, 4.6 swapped in about 5,000 miles ago. I was not having any issues after the swap until about 4,000 miles ago, I had driven out about 20 miles and parked on the side of the road with some road crown putting the passenger side of the vehicle down a little bit. Left it parked for about 2 hours, came back and started it up and noticed that the oil pressure warning light was staying on much longer. I rolled the window down to listen to the engine before I drove away and could hear that it was obviously not getting pressure, so it was something much more urgent than just a faulty sensor/wiring. I shut off the engine and checked the oil level it was ok, restarted it, light stayed on again for about 45 seconds and then finally went out and I could hear that the top of the motor finally got oil to it. So I carefully drove home, no problems on the drive home. Left it in my flat driveway for a few hours, went out to start it up and the light went out within 2-3 seconds just like it always has. Curious but relieved that I wasn't starving my new engine for oil, I drove it as I normally would. A few days later I had to park on the street overnight, when I started it up the next morning the oil light was on again and not going out. I shut the car off and started thinking about when I had seen the light come on and how the car was parked, which was both times with the passenger side of the vehicle downhill slightly. So I started it up and quickly pulled into my driveway, shut it off again, and let it sit for about a minute and restarted it and the light went out within 2-3 seconds.
So I started watching it over the next week or so and could consistently duplicate the issue by parking it with the passenger side downhill and letting it sit for 2 hours or so. I got an oil pressure gauge hooked up to confirm my suspicion that the engine was loosing its prime with sitting on an angle. I could then also see if I was getting proper oil pressures when it was running (which I was). I also started playing around with parking it drivers side down to see if it mattered which side was down and it did matter, it would only act up when the passenger side was downhill.
So I took the oil pressure relief valve out and cleaned it, although it wasn't dirty or terribly tarnished. But it made no change. I again verified the correct oil level. I sat around and scratched my head for a while and finally called a good friend that is also a Land Rover master tech. His first suggestion was to replace the Bosch oil filter I had on it for a factory Land Rover filter, because the factory filters have an anti-bleed back valve in them.
Well after 3 days of driving and parking with the passenger side downhill, the oil pressure gauge has confirmed that the bosch filter was the source of my frustrations. No longer does the engine take so long to build pressure, it will build up pressure withing 2-3 seconds whether its parked on an angle or flat ground.
SO, after much worry and stress it was as simple as an oil filter. Not saying that this will fix your problem, but its simple to try and cheap. And I wish I tried it first :smilelol:
