RXN
Active VIP Member
This is on my, 1958 Oldsmobile 371.
Two summers ago. The engine was rebuilt. New everything. Bearings, cam shaft, oil pump was new too.
Since the rebuild I went back to 5W30 synthetic oil. (I have lots at home cause I run it in everything else).
Car ran fine.
In June the oil was changed.
On Saturday I put 500 miles on.
Drove around a bit on Sunday.
Started the car today. And the oil light stayed one. (Normally it goes out after a couple seconds).
I pulled the sensor and put in a gauge. It read 2psi
According to my manual. The light comes on at 3 psi.
Talked to a few guys. All said I should not run 5w30 and I should never run synthetic.
When I dumped the oil. It looked thin. Like water. So, new filter. And put in 20W50 (a recommendation by a few others with this car). Fired it up. Gauge read 2psi.
Had my wife accelerate it a bit while I watched the gauge. Stayed at 2.
I dumped that oil. Pulled the pan. And the pump out.
I took the pump apart. (All the bolts seemed loose, barely any effort to break loose). Anyways. The gears look good. I see nothing wrong.
I pulled the relief valve. The piston has some marks on it. Can see them, but can't feel them. And it took a few good wacks on the bench to get that piston to pop out.
I'm scratching my head hard here. I really don't know why I lost pressure.
When I head back out there. I'm going to install my old pump from before the rebuild. And then try again. But If I'm still seeing 2psi, then what? From there I really don't know what to check next. Or where to go.
Any advice?
Two summers ago. The engine was rebuilt. New everything. Bearings, cam shaft, oil pump was new too.
Since the rebuild I went back to 5W30 synthetic oil. (I have lots at home cause I run it in everything else).
Car ran fine.
In June the oil was changed.
On Saturday I put 500 miles on.
Drove around a bit on Sunday.
Started the car today. And the oil light stayed one. (Normally it goes out after a couple seconds).
I pulled the sensor and put in a gauge. It read 2psi
According to my manual. The light comes on at 3 psi.
Talked to a few guys. All said I should not run 5w30 and I should never run synthetic.
When I dumped the oil. It looked thin. Like water. So, new filter. And put in 20W50 (a recommendation by a few others with this car). Fired it up. Gauge read 2psi.
Had my wife accelerate it a bit while I watched the gauge. Stayed at 2.
I dumped that oil. Pulled the pan. And the pump out.
I took the pump apart. (All the bolts seemed loose, barely any effort to break loose). Anyways. The gears look good. I see nothing wrong.
I pulled the relief valve. The piston has some marks on it. Can see them, but can't feel them. And it took a few good wacks on the bench to get that piston to pop out.
I'm scratching my head hard here. I really don't know why I lost pressure.
When I head back out there. I'm going to install my old pump from before the rebuild. And then try again. But If I'm still seeing 2psi, then what? From there I really don't know what to check next. Or where to go.
Any advice?
