nola mike
Vice Admiral
- Joined
- Apr 22, 2009
- Messages
- 5,651
TL;DR:
What would cause an oil pressure sender to fluctuate between reading correctly and reading zero?
Been chasing an oil pressure gauge/issue all summer. Mercruiser, standard analog sender/gauge. It will run fine for long stretches of time, steady at 60 psi, then drop to "zero" (actually more like 5-10, which is where the gauge reads engine off). Anywhere from a second or 2 to much longer. Goes very quickly between readings, so seemed electrical. Ran it at 3500 rpm reading zero for 10 miles a few days ago, so pretty sure at this point that it's not actually low pressure. No pattern on what triggered it or cured it, but becoming more common. Gauge checks out, all connections are squeaky clean, nothing else at the helm malfunctions when the pressure drops. Bench testing the sender checked out (I didn't have anything handy to pressurize it but readings fluctuated a bit when I blew into it). Finally swapped out the sender with a spare. So far so good, but we'll see. My concern was an intermittent clog/air leak at the pickup. Question is do senders fail in that pattern? If so, is it typically an electrical problem or something obstructing the sender hole? Doesn't really matter, just curious.
What would cause an oil pressure sender to fluctuate between reading correctly and reading zero?
Been chasing an oil pressure gauge/issue all summer. Mercruiser, standard analog sender/gauge. It will run fine for long stretches of time, steady at 60 psi, then drop to "zero" (actually more like 5-10, which is where the gauge reads engine off). Anywhere from a second or 2 to much longer. Goes very quickly between readings, so seemed electrical. Ran it at 3500 rpm reading zero for 10 miles a few days ago, so pretty sure at this point that it's not actually low pressure. No pattern on what triggered it or cured it, but becoming more common. Gauge checks out, all connections are squeaky clean, nothing else at the helm malfunctions when the pressure drops. Bench testing the sender checked out (I didn't have anything handy to pressurize it but readings fluctuated a bit when I blew into it). Finally swapped out the sender with a spare. So far so good, but we'll see. My concern was an intermittent clog/air leak at the pickup. Question is do senders fail in that pattern? If so, is it typically an electrical problem or something obstructing the sender hole? Doesn't really matter, just curious.
