Low Oil Pressure at Idle
Going to change my oil pressure sending uint tomorrow. I'll let you know if it makes any difference. My last motor use to read 80 cold 50-60 hot. And that SOB spun a rod bearing at 3500 miles. So this low pressure thing is real important to me too! I paid high dollar to get this installed less than 1500 miles ago, so I'm sure the people who installed it will fix it. I just hate to waste another day of vacation at work and have to drive 100 miles to get it worked on. I really don't think its an oil filter problem. But I''ve killed 3 shortblocks so far with spun rod bearings and believe me you don't have one or you would know it. They sound like you've got a knocking noise that sounds like it somewhere under the intake. I'm am a F-ing pro when it comes to spinning rod bearings. But what ever I find out I'll let you know. NO BS!
Last edited by NC98Z; Jul 5, 2007 at 08:18 PM. Reason: add
Thread Starter
Joined: Nov 2001
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From: Sunny San Diego
Originally Posted by edcmat-l1
You shouldnt need to run 20w50. It should have plenty of pressure with 5w30. The thichest I run in these things is 10w40. Even blower motors.
Does it knock at all when you first start it up? When rod bearings start to go, they usually will knock for just a couple seconds when you first start it up, until it gets pressure and then the knock goes away. Thats a sure sign the bearings have too much clearance.
Does it knock at all when you first start it up? When rod bearings start to go, they usually will knock for just a couple seconds when you first start it up, until it gets pressure and then the knock goes away. Thats a sure sign the bearings have too much clearance.
Originally Posted by Ed Blown Vert
Its kinda hard to hear over the blower whine. But it has always knock a bit at startup and after warming up. (It never goes away) I always thought it was our dreaded piston slap.
Thats the one clear wat to differentiate between a bearing knock and piston knock. Piston knock gets better as the temp goes up. Bearings get worse as the temp goes up. The oil gets thinner and theres less cushion.
Thread Starter
Joined: Nov 2001
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From: Sunny San Diego
Originally Posted by edcmat-l1
Piston slap should diminish with increased temp. As the engine heats up, the pistons swell to better fit the bore. I've heard some that dont go away completely, but all of them I've ever seen/heard get better with temp.
Thats the one clear wat to differentiate between a bearing knock and piston knock. Piston knock gets better as the temp goes up. Bearings get worse as the temp goes up. The oil gets thinner and theres less cushion.
Thats the one clear wat to differentiate between a bearing knock and piston knock. Piston knock gets better as the temp goes up. Bearings get worse as the temp goes up. The oil gets thinner and theres less cushion.
I just put in 20-50w and pressure was about the same. Just a bit higher.
Cold = 30#
Hot = 20#
My oil pressure is still doing some weird ****. At cold start up its at 45-50psi. And for the first 20-25 minutes it will go to 55-60psi cruising. Then at hot idle it is around 35-38psi. and at 40-42psi at cruising. Now when I go WOT it will go to 55-60psi so I should be fine. But today after I made two or three runs it wouldnt go over 45psi. Would that be because the oil got too hot and was thin or what? I have a tr224 cam and ls6 oil pump. 10/40 regular oil w/fram filter.
did you try the new sender or at least verify the guage is even right? you know cam bearings will cause low oil psi like this too! I would have to check the ls1 oil flow but I would be sure that is another good source. I have seen this countless times on other cars. often on DOHC ones that don't use bearings.
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Thread Starter
Joined: Nov 2001
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From: Sunny San Diego
Originally Posted by 89 formula350
did you try the new sender or at least verify the guage is even right? you know cam bearings will cause low oil psi like this too! I would have to check the ls1 oil flow but I would be sure that is another good source. I have seen this countless times on other cars. often on DOHC ones that don't use bearings.
Car still runs great. If it wasn't for the low pressure, I wouldn't think anything was wrong.
Thread Starter
Joined: Nov 2001
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From: Sunny San Diego
Originally Posted by ShevrolayZ28
Just tagging along....
Hey, was there any metal on the drain plug when you changed the oil?
Hey, was there any metal on the drain plug when you changed the oil?
Originally Posted by Ed Blown Vert
Just some very fine gray particles.
good luck.
Thread Starter
Joined: Nov 2001
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From: Sunny San Diego
Originally Posted by nvmy2000ss
I would cut open the filter and make sure theres no metal in it. Did you have good oil pressuere b4 and did it just recently start to do this? I had 20-25 psi on mine at idle when it was hot. I know when you have race bearings they have a bit more clearence between them which can cause pressure to be a bit lower but as long as you get 10psi per 1000rpm you should be ok.
good luck.
good luck.
It ended up being a loose 02 sensor plug. Once it was fixed, the car ran fine. If it wasn't for that, I wouldn't have thought anything was wrong with the car.
I am getting the 10# per 1000rpm.
get a mechanical gauge before you panic.
my stocker shows like 50psi cold when my mech. shows 60+psi.
and when its hot forget it , completely inaccurate it stays at 30psi at idle
and doesn`t move
when my mech. shows 45psiand hits 60+psi.
and if anyone wants to talk **** my car has seen very high constant rpms
and is street driven.
get a gauge then go from there.
my stocker shows like 50psi cold when my mech. shows 60+psi.
and when its hot forget it , completely inaccurate it stays at 30psi at idle
and doesn`t move
when my mech. shows 45psiand hits 60+psi.
and if anyone wants to talk **** my car has seen very high constant rpms
and is street driven.
get a gauge then go from there.
Teching In
Joined: Apr 2004
Posts: 23
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From: North East Md
I have the same oil pressure around 20-25# after it is hot, but when it's cold around 45-50# . I have been running 5w-30 in mine forever it runs fine. If you start seeing white smoke and a burning smell when you start up you can have a rod bearing or oil pump. Lets hope that none of the above is your problem and you will be fine with the filter change.
Thread Starter
Joined: Nov 2001
Posts: 3,066
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From: Sunny San Diego
Search is down. What is the best way to hook up a gauge??
There is no white smoke and no burning smell. I have ran it up to 6000 and it pulls real hard with no issues.
There is no white smoke and no burning smell. I have ran it up to 6000 and it pulls real hard with no issues.