I rebuilt my LS engine last year and shortly after I noticed my engine would make a wrapping sound for a second on first start up and the oil pressure would take a second to come in, my oil pressure light comes on for a very quick second, sounds like i just changed my oil filter or something every time is start it when its been sitting for a while, if I start it up, shut it off and start it up again within a few hours its fine. I belive the oil is draining back, now my motor has 80,000miles before the rebuild and has about 12,000 now and I think its time to do something, I never touched the oil pump when I pulled the motor apart but I did prelube the system before initial start, what do you guys think is the cause of my drain back problems? i tried a few different filters, mostly fram but im still getting the same problem.
Kyle

I did post this on Tech but have no responces yet so hopfully you guys will know what causes my drain back problems

 

wrapping? as is rapping like piston slap?

 

Im not buying your drain back theory. There may be something wrong with your oil system. The oil pump should always get replaced with a new build. Do you have an oil pressure gauge? Its normal for the oil light for 1 sec after initial start up. But anytime after that, it means pressure is dangerously low, <5psi.

 

I thought it was piston slap too and it may be but the oil pressure guage shows low for a second but then goes up to normal specs.

 

plus if I crank it for a few seconds to build oil pressure there is no problem, it only happens for more then 1-2 seconds at the most so its hard to belive i would only get piston slap for that short, unless stuff warms up that fast.

 

why dont you put a new pump on it first? Just in case it is the pump.

 

well I was wondering if there is any anti-drain back valves or anything to replace or a specific part in the pump the may of gone bad. it has less then 100k miles on the pump and 70,000 was driven by an middle age lady with all proper maintance done so i highly doubt the whole pump needs to be replaced, I suppose I could pull it apart and check clearances but thats not to fun so I would like to get a good idea of what it could be before I do it.