Hi. I just got a 1991 Power Ram w150 with 175,000 miles. The oil pressure light would flicker when I stopped at a red light and the pressure guage never goes more than 1/4 the way up. After reading a lot of forums, I figured the culprit was either sludge or the oil pump. I bought a new oil pump, primed it by filling it with 90w gear oil, and installed it. There was no sluge in the oil pan but I did find chipped off pieces of the rubber oil pan gasket in the oil pump screen. After installing the pump and adding fresh 10w30 oil, i started it up. The oil pressure guage stayed at dead zero while I ran the engine a good 20 seconds. The top end started to clatter a little bit so I shut it off. I'm afraid to start it up again without any pressure. It's about 25-30 degrees out here. Any suggestions?

 

80 WEIGHT OIL IS TOO THICK TO PRIME AN OIL PUMP WITH. GIVE THE PEMP TIME TO DRAIN THE 80 WEIGHT OIL DOWN AND TRY TO START THE MOTOR AGAIN. MORE THAN LIKELY THE THICK OIL CLOKED OUT THE PUMP AND YOUR HYDRAULIC LIFTERS STARTED TO COLAPSE CAUSING YOUR TOP END TO "CHATTER". FACTOR SPECS CALL FOR30-80 LBS OF PRESSURE @ ABOUT 2500 RPM'S. THESE NUMBERS WILL BE A LITTLE LOWER WITH HIGH MILES. yOU MAY HAVE A FAULTY SENSOR TRIGGERING YOUR OIL LIGHT. YOUR BEST BET IS TO PULL THE SENSOR AND INSTALL A PRESSURE GAUGE IN ITS PLACE. THE STOCK GAUGES ARE KNOWN TO STICK. TAP ON THE INSTRUMENT CLUSTER AND SEE IF THE NEEDLE JUMPS UP.[8D]

 

90 WEIGHT OIL IS TOO THICK TO PRIME AN OIL PUMP WITH. GIVE THE PEMP TIME TO DRAIN THE90 WEIGHT OIL DOWN AND TRY TO START THE MOTOR AGAIN. MORE THAN LIKELY THE THICK OIL CLOKED OUT THE PUMP AND YOUR HYDRAULIC LIFTERS STARTED TO COLAPSE CAUSING YOUR TOP END TO "CHATTER". FACTOR SPECS CALL FOR30-80 LBS OF PRESSURE @ ABOUT 2500 RPM'S. THESE NUMBERS WILL BE A LITTLE LOWER WITH HIGH MILES. yOU MAY HAVE A FAULTY SENSOR TRIGGERING YOUR OIL LIGHT. YOUR BEST BET IS TO PULL THE SENSOR AND INSTALL A PRESSURE GAUGE IN ITS PLACE. THE STOCK GAUGES ARE KNOWN TO STICK. TAP ON THE INSTRUMENT CLUSTER AND SEE IF THE NEEDLE JUMPS UP.[8D]

 

I wouldn't trust the factory gauges. Mine dropped to 0 once while driving down the road, but I know it wasn't right. It's an electric sensor, so look at it on the back of your motor by the distributor and see if the wires have rubbed or come unplugged. You could also clean it up a bit. Mine was leaking a fair amount and everything was soaked.