flyingmonkey1

About half a year ago, I was doing a pull getting onto the highway, and about 3/4th the way up the rev range, I noticed the oil pressure dipped and the warning light came on. Probably dipped to about 10 psi. I immediately backed off, and gingerly cruised the ~1.5 miles back home and throughout that time, the oil pressure was fluctuating between 20 and 40 psi (with ~40psi being normal for warm oil temps in this car). As I was getting back home, the oil pressure dropped to 0 and I immediately killed the car, and ended up pushing it back the rest of the way. And there it sat as I was unfortunately in the process of moving and hadn't had time to deal with it. I had just assumed the engine needed a rebuild at that point. Well fast forward to a week ago, I changed the oil, and didn't notice anything unusual in the drained oil. Refilled it, and finally started it last night, and it started up just fine, and idled at ~70 psi cold. Warmed up and got to the normal 40 psi, with no dipping to speak of. When the engine is reved up, the oil pressure followed. The engine sounds completely fine as well. So I'm thinking the engine is perhaps okay, and its more an oil pump issue, or sensor issue at this point. Any ideas here, or has anyone run into something similar? The engine has an aftermarket Katetch oil pump, could it fail in this way? I had always been under the (perhaps incorrect) assumption that an oil pump either worked, or it didn't. Any ideas would be appreciated.

MTBSully

Was the car low on oil? Could have been sucking the pan dry if the oil level was low. Or could have been a faulty sensor. I'd keep an eye on it but its probably fine. If it happens again be sure the oil level is full, then check with a mechanical guage.

USAF

Start cheapest first.
Change the oil sensor.
Then the pump.

I'm betting on one of those 2

USAF

Orion2011

There are also some o-ring seals inside the engine that can cause oil pressure issues. The main one is the oring on the oil pickup tube going to the oil pump.

flyingmonkey1

So I don't think the engine was low on oil, and I guess I forgot to mention, it has the LS7 dry sump system as well, so I don't think it should have sucked anything dry. I suppose I can start with an easy swap on the sensor and go from there. Could an incorrectly installed or failing oring cause an intermittent pressure like this? Everything in the engine has about 10k miles on it so far, so I'm thinking anything incorrectly installed up to this point should have stuck out.

Sledge Hammer

I just had this same issue. So I changed the sensor. Not as easy as you might think because access is terrible. I had to remove the intake to gain access. It seemed to fix the problem for about two weeks, and then it dropped to zero again so I took it to the dealer, They had it for a week and concluded it was a bad gauge cluster claiming there was an intermittent short. They said the gauge cluster is no longer manufactured but If I could find one they would program it and put it in. I found one with Cultrag Performance and they programed it with the correct mileage. Since the dealer wanted another $169 dollars I installed it myself in about an hour. It has been two weeks now and no further issues. Keeping my fingers crossed.

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