Katsumoto-sengi

2000 C5 LS1 modded to LS7, 15K miles on motor, recently low oil pressure readiings, checked with Kent Moore adapter and mechanical gauge at filter housing, 30+ lbs at idle (hot), dash gauge reads 20 and gradually falls to 6, kicks "low pressure" alert. Mechanical gauge still reading 30+ lbs. Changed the sensor (alum body) to new brass body. After change, Functioning same. Very annoying to get the "ding, ding". Pressure rises from 30 with rpm increase, falls back to 30+ at idle. Anyone every seen the gauge fail. Also cut filter, no debris. regards

jedblanks

What year ls7? Lots of 2010+ ones with spun bearings. Apparently a supplier issue.

And c5 oil pressure sensors are notorious for failing but usually are off scale high.

ZeeOSix

Obviously an electrical and/or in dash gauge problem if the mechanical oil pressure gauge never shows abnormal oil pressure. Also, the brass bodied oil pressure sensors are supposed to be the best, and if you installed a new one then I'd rule that out. No real idea where to suggest to start ... need the electrical gurus to chime in.

Does the DIC readout for oil pressure follow the gauge reading?

Katsumoto-sengi

I built the LS7 in 2002 from LS1 block, Darton sleeves, Callies crank, Diamond Pistons, ported 853 heads, Chet Herbert cam.

The DIC reading follows the dash gauge whereas the mechanical gauge off the filter housing is consistently 30+ and will rise and fall back as RPM increases/decreases