Think my LT1 oil pickup is bad. Suggestions?
04-11-2013, 07:10 PM
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Think my LT1 oil pickup is bad. Suggestions? My 94 Z28 has been making a noise like this (not my video, but identical noise):
The poster says it was a rocker hitting a stud, my friend and I looked and that's not my problem.
That noise started off intermittent, it would act up if you reved the engine up past 4,000 rpm, and would go away a few minutes later. Now it's pretty much constant. It seems to run fine, idles smooth and makes power, it just makes that noise all the time. It doesn't seem to get worse with load. I don't know how long it's been like this, I just bought the car last December, stored it for the winter and haven't had much time behind the wheel. It did it for about 30 seconds on the test drive, went away before I could stop, jump out and open the hood and I thought it was the serpentine belt slipping, so it didn't concern me much.
So my friend noticed there is no oil pressure in the top end when we run it without the valve covers on, so took off the intake and went hunting for a bad lifter or out loose rocker. The valvetrain seems to be fine, nothing out of adjustment or damaged, so he's thinking it's oil pickup.
Oil pressure seems fine when I first start it. Hovers around 40psi at cold idle, peaking a little bit higher when driving. Once it warms up, it can dip to slightly above the red line (20ish I believe) at hot idle, but hits 40 again when the engine is revved up to 1,500 - 2k . That's assuming the stock gauge is measuring accurately.
No metal shavings in the oil, everything seems fine aside from the noise and the low oil pressure reading at hot idle.
So if the oil pickup has fallen off, should I just tack weld it like a lot of people seem to do, or replace the whole pump with a Melling Select?
And what's the risk that it's done serious damage to my bottom end? Should I expect to need a rebuild or a swap soon? Since we'll be putting it on a lift and pulling the oilpan soon, should we throw in fresh rod bearings? Or is silly to do bearing without having the crank inspected/turned? Am I over-reacting?
The poster says it was a rocker hitting a stud, my friend and I looked and that's not my problem.
That noise started off intermittent, it would act up if you reved the engine up past 4,000 rpm, and would go away a few minutes later. Now it's pretty much constant. It seems to run fine, idles smooth and makes power, it just makes that noise all the time. It doesn't seem to get worse with load. I don't know how long it's been like this, I just bought the car last December, stored it for the winter and haven't had much time behind the wheel. It did it for about 30 seconds on the test drive, went away before I could stop, jump out and open the hood and I thought it was the serpentine belt slipping, so it didn't concern me much.
So my friend noticed there is no oil pressure in the top end when we run it without the valve covers on, so took off the intake and went hunting for a bad lifter or out loose rocker. The valvetrain seems to be fine, nothing out of adjustment or damaged, so he's thinking it's oil pickup.
Oil pressure seems fine when I first start it. Hovers around 40psi at cold idle, peaking a little bit higher when driving. Once it warms up, it can dip to slightly above the red line (20ish I believe) at hot idle, but hits 40 again when the engine is revved up to 1,500 - 2k . That's assuming the stock gauge is measuring accurately.
No metal shavings in the oil, everything seems fine aside from the noise and the low oil pressure reading at hot idle.
So if the oil pickup has fallen off, should I just tack weld it like a lot of people seem to do, or replace the whole pump with a Melling Select?
And what's the risk that it's done serious damage to my bottom end? Should I expect to need a rebuild or a swap soon? Since we'll be putting it on a lift and pulling the oilpan soon, should we throw in fresh rod bearings? Or is silly to do bearing without having the crank inspected/turned? Am I over-reacting?
04-11-2013, 08:16 PM
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04-11-2013, 08:27 PM
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184,000 miles
Cold air intake, Headers, axle-back flowmaster. Hypertech Power Programmer (not sure if program is installed on the PCM, haven't played with it)
Not sure what oil was in it when I bought it. Drained it out a 2 weeks ago, put in Shell Rotella Synthetic 5W-40 and drove about 40 miles since.
Cold air intake, Headers, axle-back flowmaster. Hypertech Power Programmer (not sure if program is installed on the PCM, haven't played with it)
Not sure what oil was in it when I bought it. Drained it out a 2 weeks ago, put in Shell Rotella Synthetic 5W-40 and drove about 40 miles since.
04-11-2013, 08:47 PM
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My guess would be cam bearings. Run a thicker oil and see if it holds better pressure at idle. Check the pickup when you change the oil but a rebuild may be knocking at your door.
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04-12-2013, 08:43 AM
#8
if there is oil pressure on the gauge then I doubt the pickup has fallen off........sounds like maybe theres some crud stuck in a oil galley near the lifters or something...maybe its just a bad lifter and all the oil pressure is being bled off through that lifter, hence your noise also....oil is like electricity its gonna go to the easiest place to escape first......if the pickup fell off youll have no pressure on the gauge.........
