Finlay Macpherson

hi all

after a number of issues resolved with my 2004 LS1, the engine was running sweet as a nut and made 321 whp and 345 flt/lbs @ wheels, ran perfect for about 3 or 4 days then boom ! no oil pressure so i killed the engine waited a min or so then fired it back up with normal oil pressure so i put it down to a faulty switch but yesterday morning i fired it up again, boom ! no oil pressure so just to make sure it was genuine i removed the oil pressure sender and tied in a mechanical gauge, fired it up again and ran (not for long), no oil pressure, tried it again for 10 secs with a different gauge, no oil pressure and you could start to hear the engine get rattly which also tells me no oil getting to heads.

today i stripped out the oil pump, looks brand new, im sure the relief valve was stuck shut so removed the spring and freed off, ive stripped possitive displacement pumps before that looked brand new but were actually faulty so could this be the same deal here ?

has anyone else had similar issues ? im at a loss now what to do, do i just buy and fit a new pump or do i investigate further ? is there anything else that could be a fault ?, engine has just been comp tested and was spot on, its done just under 80K

has anyone got any ideas ?

many thanks for help and replys :-)

cheers

Finlay

Old Geezer

iTrader: (3)

What does the pick up tube seal ring look like??

LLLosingit

iTrader: (4)

I would agree that it was most likely the oil pump bypass sticking, Nothing else I could think of would explain a sudden total loss of pressure then back to normal. If it was anything to do with wear then it wouldn't suddenly regain normal pressure.