REDRED

Anyone ever have this happen before? When I started the car this morning I had 0psi oil pressure for about 5 seconds then it recovered to around 38psi. The car had sat overnight, on a slight uphill incline and it was around 45F outside. Oil is about 1/2 quart low. Ity sounded terrible during that rough start too Thoughts?

JS

JJC5

There's a check valve that prevents the oil from draining back to the pan when the engine is off so that when you start it again, there will be immediate oil pressure. I believe that's where you need to start looking.

cclive

It takes a few seconds for the gauges to start up, so you will get no valid reading until then.

brooklync5

I had an issue like this on my c5 except the oil pressure read 0 and stayed there. Turned out to be a bad sensor.

JJC5

But not five seconds. Plus he's getting noise which I'm guessing is lifters and that coincides with no oil pressure at start up. I've not heard of this problem with the LS motors though.

jack5hd

what oil filter do you have?

JCtx

Yeah, that's the bad part of 'keyless ignition'; I always like to wait a few seconds after ignition, until all self-diagnostics are done. Will check next time how long from cranking the engine to showing oil pressure next time. It might be less than 5 seconds, but it's definitely not immediate.

Finally, with the oil filter upside down under the engine, I doubt there's any 'check valve' in there, but could be wrong. I sometimes don't use the car for weeks, and zero noises at start-up. On the other hand, with DOHC engines and oil filters upside down ON TOP of the engine, like the M3 and the new Azera, you typically hear a bit of valvetrain clatter for a second or two before they quiet down. Even with check-valves, it takes a bit longer to build oil pressure after a cold start. Hopefully the OP didn't experience piston-slap, which I had on both the LS1 and LS2 engines. It's rare on LS3s, but I've read of a few with the affliction. Good luck.

todm

I would take it to the dealer. Mine did the same thing and I had to have the pump replaced two different times. Pain in the butt! The first time it read zero oil pressure, a year later it read low oil pressure. Take it in before you damage something.

bdspell

i'm remerbering big problems with fram oil filters a few years back .the internal valves leaking and people having 0 oil preasure at start up check your filter if its a fram it may be one of the older bad ones