Low oil pressure when hot
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Low oil pressure when hot 2011 5.3L. We did a Texas Speed DOD delete, replaced the oil pump, and added a pan plug. It ran well initially, but as soon as the coolant hits 200°F or higher, the oil pressure drops to 10 PSI or below and won’t increase with RPM. Before reaching that temperature, though, the oil pressure fluctuates normally with RPM and even climbs to nearly 80 PSI. We replaced the oil pressure sensor, but the issue persisted. We disassembled it again to inspect the pickup tube O-rings and camshaft bearings. Everything seemed fine, but we decided to replace the cam bearings anyway. Since we could pull the engine quickly, we did. Upon teardown, all bearings actually looked good. We rebuilt the engine with new cam bearings, another new oil pump, all-new gaskets, a barbell plug upgrade, and followed the manual meticulously. After the first startup, it ran well initially, but the oil pressure dropped instantly again once temps hit 200–210°F. We installed a new valley cover (in case of out-of-spec components or O-ring issues), but that didn’t fix it. A mechanical gauge reads ~15 PSI at 210°F coolant temp, but the pressure doesn’t fluctuate with RPM. Peering into the valve cover’s oil fill hole, oil is visibly flowing over the rockers. When revving, oil sprays everywhere—but the mechanical gauge’s tube only drips oil, suggesting low flow. After dropping the pan, the pickup tube O-ring appeared intact. We pulled a couple of piston rod bearings, and they looked brand new, as expected. Has anyone encountered this issue or have ideas about what we’re overlooking? Could it be a blocked passage, pump alignment, or something else?
Last edited by OutlawRed666; Apr 15, 2025 at 08:23 PM.
2011 5.3L. We did a Texas Speed DOD delete, replaced the oil pump, and added a pan plug. It ran well initially, but as soon as the coolant hits 200°F or higher, the oil pressure drops to 10 PSI or below and won’t increase with RPM. Before reaching that temperature, though, the oil pressure fluctuates normally with RPM and even climbs to nearly 80 PSI. We replaced the oil pressure sensor, but the issue persisted. We disassembled it again to inspect the pickup tube O-rings and camshaft bearings. Everything seemed fine, but we decided to replace the cam bearings anyway. Since we could pull the engine quickly, we did. Upon teardown, all bearings actually looked good. We rebuilt the engine with new cam bearings, another new oil pump, all-new gaskets, a barbell plug upgrade, and followed the manual meticulously. After the first startup, it ran well initially, but the oil pressure dropped instantly again once temps hit 200–210°F. We installed a new valley cover (in case of out-of-spec components or O-ring issues), but that didn’t fix it. A mechanical gauge reads ~15 PSI at 210°F coolant temp, but the pressure doesn’t fluctuate with RPM. Peering into the valve cover’s oil fill hole, oil is visibly flowing over the rockers. When revving, oil sprays everywhere—but the mechanical gauge’s tube only drips oil, suggesting low flow. After dropping the pan, the pickup tube O-ring appeared intact. We pulled a couple of piston rod bearings, and they looked brand new, as expected. Has anyone encountered this issue or have ideas about what we’re overlooking? Could it be a blocked passage, pump alignment, or something else?
