Low oil pressure on 98 ls1
#1
Low oil pressure on 98 ls1
I just purchased a 98 z28 with 99k. I noticed the oil pressure was a little low. It's not too bad but at idle its around 30 and it holds 40-45 at 3k. The oil level is fine and I dont think its a rod bearing because there is zero knocking. How can I tell if it's the oil pump? Also, the idle is around 1200 rpm...what other possibilities can there be besides a vaccum leak for this?
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Have you changed the oil since you bought it? I would do an oil change and make sure it has some good synthetic oil in it since you don't know how long it's been since it's been changed or what's in it.
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Thats sounds about right. When I start my car the pressure is usually at 45psi and drops to about 35psi at idle (1000rpms). A key factor in this also is the weight of the oil used and how hot it is outside. On a really hot day in rush hour traffic my psi dropped to about 20psi. I'm running 10/30 fully synthetic oil, a little thicker than normal because high heat will thin it out.
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Originally Posted by ComNGetSum
Thats sounds about right. When I start my car the pressure is usually at 45psi and drops to about 35psi at idle (1000rpms). A key factor in this also is the weight of the oil used and how hot it is outside. On a really hot day in rush hour traffic my psi dropped to about 20psi. I'm running 10/30 fully synthetic oil, a little thicker than normal because high heat will thin it out.
The last number in the series is all you need be concerned about in any weather over about 34 degrees.
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Originally Posted by edcmat-l1
10/30 is no thicker than 5/30. The first number, followed by a 'w' is the 'winter' weight. These oils are 'multi weight', or muti viscosity, so they act like a 5 weight oil under like 34 degrees, and then when they heat up and the polymers expand, they act like a 30 weight.
The last number in the series is all you need be concerned about in any weather over about 34 degrees.
The last number in the series is all you need be concerned about in any weather over about 34 degrees.
#9
Originally Posted by tylerdj
Have you changed the oil since you bought it? I would do an oil change and make sure it has some good synthetic oil in it since you don't know how long it's been since it's been changed or what's in it.
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Originally Posted by 3fingas
port that oil pump and get a shim for the relief spring. You should see +8-10 psi easy
#14
So I changed the oil with mobil 1 and k&n filter and the pressure is better but the idle is still high. I adjusted the set screw all the way out and it's still at 1100-1200 rpm. Should I start looking for vaccum leaks? Where do these cars usually leak at?
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Originally Posted by stevied916
So I changed the oil with mobil 1 and k&n filter and the pressure is better but the idle is still high. I adjusted the set screw all the way out and it's still at 1100-1200 rpm. Should I start looking for vaccum leaks? Where do these cars usually leak at?
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Ive noticed...atleast in my experience that 98's usually hold lower oil pressure...so urs sounds about right....
Mine holds 40 at a hot idle and just under 80 at WOT....but if i run it around town with the AC on it only holds about 30psi at hot idle. not to jack the thread but is mine the only one that does that?
Mine holds 40 at a hot idle and just under 80 at WOT....but if i run it around town with the AC on it only holds about 30psi at hot idle. not to jack the thread but is mine the only one that does that?