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05 CTS-V - have owned this car for 5 years. 3 years ago low oil pressure warning - dash dinging and pressure ZERO. Would happen intermittent but ALWAYS happened on startup only and would go away after 10-30 seconds. New oil pressure sensor fixed for 1 year then happened again on start up after tracking the car. Replaced another oil pressure sensor and OK for another year. This year started her up a 3rd time out tracking and low pressure warning for 30 seconds, then went off. 4On start up before 4th time out track went off for 90 seconds then pressure reading back up. end of day started up to drive home and alarm constant. After 5 minutes heard lifter sounds and shut down immediately. Tearing the front of motor off showed oil pressure relief valve stuck open. New oil pump and pressure relief valve. 250 miles later and alarm is going off AGAIN. What's up????? GM said no issues they are aware of. Start up sometimes 1 PSI, sometimes 25, sometimes 70. When warm, reads 55-60.
any suggestions appreciated.
Ron

Lbar

I would run new wires to the sensor.

DMM

Check it with a mechanical gauge. The oil pump pressure relief valve can gat seized in the bore and dump oil causing a low oil pressure situation. You'll most likely need a new pump which isn't a huge deal, just a PITA to get the 8mm pick up tube bolt off.

I always use the LSA high pressure high volume pump since they're about $80 at the dealer. Might wan to install and LS2 timing chain while you're in there too.

raven154

iTrader: (14)

First, install a mechanical oil pressure gauge to to see what's really going on. The oil pressure senders are junk and fail often as you have witnessed.