Oil pressure warning in 95 jetta

[o17541]

I have a 1995 Volkswagen Jetta III GL and after about 15 minutes my low oil pressure light comes on with the buzzer. I checked the oil level multiple times and it has always been good. I replaced the oil pressure sensor but the problem still exists. The car is not overheating, it just gets up to 160 and the low oil pressure light and buzzer come on and won’t go off. I just changed my oil and oil filter 2000 miles ago and currently have 10w-30 oil in it. Why does the oil pressure warning keep going off?

[Doug Tatham]

As it warms up the oil becomes thinnner. There is always leakage past the bearings, but as the bearings become worn, the leakage becomes greater. You'll probably find that if you increase the idle to 15,000 the alarm stops, but at 20000 it starts again. This is when the second (higher pressure sensor) alarms. You probably have bad rod bearings or main engine bearings. Hopefully your crank shaft and piston rods are ok. The cylinder head/cam has "bearings" machined into it. You'll want to plastigage all of them. Replacing the bearings isn't very hard to do, but if there is excessive wear to to the block or shafts you'll probably be better off pulling the engine. One quick fix is to add Lucas oil stabilizer or change to 10W40. Also, inspect your spark plugs for excessive carbon buildup and check your compression to be sure your pistons are ok. You can pick up an oil pressure gage from harbor frieght for about $10. It's best to check to see if the oil pressure is actually dropping before going forward. The alarm may be caused by the sending unit and everything else is ok. This is unlikely.