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Discussion Starter #1
So I have a 1999 Z71 silverado with the 5.3L. The truck is 4x4 and has the 4L60E. My question has to do with what kind of oil pressure I should be running. From the threads I searched, it looks like I should have at least 60psi when I am driving on the freeway. I am lucky if I push 40 psi doing 70mph. While sitting at an idle, it drops as low as 18-20psi. I keep up on maintance, but the truck does have 200k on the clock. When I first bought it, it carried high oil pressure, but that was 100k ago. It seems like it just dropped this low recently. Any ideas on what I can do to fix it? Thanks.
 

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Toxic Masculinity
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Welcome to the forums...

There's not much you can do and to be honest I wouldn't worry about it. The clearances are just getting looser on the pump, rod and main bearings which is normal. You'll here people say to run a higher viscosity oil which will show more pressure on the gauge but it's just a psychological fix as it will not protect the engine any better and in some instances be less protection. Using a higher viscosity oil requires more energy to pump thus reducing gas mileage and horse power. If a 750+HP Nascar engine can run all day at 20 pounds... your good at 40 lbs. Just enjoy the extra few horsepower a loose clearance motor gives you. When she starts smoking and consuming oil think about freshening everything up then.
 

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Discussion Starter #3
Alright thanks for the reply. I figured it had allot to do with its age and miles, just wanted to make sure it wasn't something I needed to worry about.
 

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20 at idle is way more than fine.

People that build race engines usually try to keep it low to reduce the horsepower lost working to pump the oil.
 

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The Cheese Grater
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i had a problem like this with my 99 silverado but its not a z71. i had to replace the oil pick up tube and rubber seal connecting it to the oil pump and it made me get 40psi at idle and up from there. You should be fine if youre still getting pressure even if its that low.
 

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I have a 2008 silverado 1500 with a 5.3. I have changed the oil in it 600 miles ago and i have watched my oil pressure drop. I changed the filter and I regained oil pressure back. I cut the filter apart and found nothing. why would that happen
 
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