Low oil pressure SER1 L67
08-03-2004, 08:21 PM
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Low oil pressure SER1 L67
Ive noticed lately (mostly after my exhaust was installed) that my oil pressure has dropped from about 40 psi at idle to about 35 when in park, ive seen it go as low as 25 psi when idling in traffic on a hot day...Is this normal or am I looking at a potential future problem....dont want to waste the Mobil 1 by not pumping it through fast enuff!!!
08-03-2004, 10:32 PM
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Sounds a lot like mine too. There was a thread on here a while ago that may be of interest. It was something about oil pressure in relation to the brand of oil filter you use. Something about some gave higher readings than others. Otherwise, sounds like normal wear and tear to me... no matter how much we wish it is always at 40+ 
08-03-2004, 10:38 PM
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someone once told me that engines really dont need that much oil pressure, he said something like a SB chevy only needs like 10 psi oil pressure at idle, seemed a little wierd for me, but I guess as long as everything is being lubricated then I should be ok....Ive never seen it drop below 25 psi and it only dropped that low today in stop and go traffic with the AC on in 107 degree (heat factor) weather with insane humidity. My heat gauge was measuring at 225+ at times too, which is probably normal due to the circumstances but in 75-80 degree weather its ussually around 190.
08-04-2004, 01:02 AM
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I have one of the higher pressures here, always 40psi+ at hot idle. Try a K&N oil filter next time and see if it goes up. Driverjohn runs one, too. Maybe he can compare his pressures.
08-04-2004, 10:05 AM
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Originally Posted by jr's3800
Originally Posted by TrueWildMan
Originally Posted by jr's3800
... The lowest I usually have is 30 psi on my 95 and 35-40 psi on my 91...
I *'pose one of those is 95??
08-04-2004, 06:00 PM
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-can't resist a couple of comments: -a sort of "for what it'* worth,,"
Since mention was made to the SB Chevy, the "GENERAL RULE OF THUMB" for the Chevy is, "Safe oil pressure is 10 psi for each 1000 engine rpm." -and that statement is to be found in numerous books. (the curious question I have is, "so how about those 6, 8, & 10 thousand rpm chevys (?maybe NASCAR?) -are they really running 60, 80, and 100 psi ?? -hmmm,, I wonder,,,)
I guess from a purely mechanical engineering stand point, oil pressure by itself has essentially nothing to do with the adequate and safe lubrication of an internal combustion engine. :? HOLD ON NOW, KEEP READING :? That is purely a matter of film strength (-and film thickness, to a degree). So why do we need a certain amount of pressure then? The answer is, to always ensure the delivery of an adequate supply of oil film. (and the first parts that come to my mind is connecting rod bearings when operated at high rpm. -the various forces at play are fairly substantial !) Also engine oil plays a pretty large part in the removal of heat from almost all internal engine parts, so consequently a certain amount of continuous re-supply is necessary. And pressure certainly helps assure continuous re-supply.
Another factor that comes back to my old mind is that "minumum safe oil pressure" is also dependant on individual engine designs. SO THE BOTTOM LINE is, follow the recommendation of the engine manufacturer. I remember one other forum topic some time ago someone had quoted the specifications right out of the GM shop manual. I am sorry I don't have that book available right here now, or I would look it up and re-state it. I do seem to remember that the minumum safe pressure was higher than the SB Chevy.
So, how is that for WAY MORE information than anyone really wanted to know?
Since mention was made to the SB Chevy, the "GENERAL RULE OF THUMB" for the Chevy is, "Safe oil pressure is 10 psi for each 1000 engine rpm." -and that statement is to be found in numerous books. (the curious question I have is, "so how about those 6, 8, & 10 thousand rpm chevys (?maybe NASCAR?) -are they really running 60, 80, and 100 psi ?? -hmmm,, I wonder,,,)
I guess from a purely mechanical engineering stand point, oil pressure by itself has essentially nothing to do with the adequate and safe lubrication of an internal combustion engine. :? HOLD ON NOW, KEEP READING :? That is purely a matter of film strength (-and film thickness, to a degree). So why do we need a certain amount of pressure then? The answer is, to always ensure the delivery of an adequate supply of oil film. (and the first parts that come to my mind is connecting rod bearings when operated at high rpm. -the various forces at play are fairly substantial !) Also engine oil plays a pretty large part in the removal of heat from almost all internal engine parts, so consequently a certain amount of continuous re-supply is necessary. And pressure certainly helps assure continuous re-supply.
Another factor that comes back to my old mind is that "minumum safe oil pressure" is also dependant on individual engine designs. SO THE BOTTOM LINE is, follow the recommendation of the engine manufacturer. I remember one other forum topic some time ago someone had quoted the specifications right out of the GM shop manual. I am sorry I don't have that book available right here now, or I would look it up and re-state it. I do seem to remember that the minumum safe pressure was higher than the SB Chevy.
So, how is that for WAY MORE information than anyone really wanted to know?
08-04-2004, 11:03 PM
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Originally Posted by 57chevythunder
-can't resist a couple of comments: -a sort of "for what it'* worth,,"
Since mention was made to the SB Chevy, the "GENERAL RULE OF THUMB" for the Chevy is, "Safe oil pressure is 10 psi for each 1000 engine rpm." -and that statement is to be found in numerous books. (the curious question I have is, "so how about those 6, 8, & 10 thousand rpm chevys (?maybe NASCAR?) -are they really running 60, 80, and 100 psi ?? -hmmm,, I wonder,,,)
I guess from a purely mechanical engineering stand point, oil pressure by itself has essentially nothing to do with the adequate and safe lubrication of an internal combustion engine. :? HOLD ON NOW, KEEP READING :? That is purely a matter of film strength (-and film thickness, to a degree). So why do we need a certain amount of pressure then? The answer is, to always ensure the delivery of an adequate supply of oil film. (and the first parts that come to my mind is connecting rod bearings when operated at high rpm. -the various forces at play are fairly substantial !) Also engine oil plays a pretty large part in the removal of heat from almost all internal engine parts, so consequently a certain amount of continuous re-supply is necessary. And pressure certainly helps assure continuous re-supply.
Another factor that comes back to my old mind is that "minumum safe oil pressure" is also dependant on individual engine designs. SO THE BOTTOM LINE is, follow the recommendation of the engine manufacturer. I remember one other forum topic some time ago someone had quoted the specifications right out of the GM shop manual. I am sorry I don't have that book available right here now, or I would look it up and re-state it. I do seem to remember that the minumum safe pressure was higher than the SB Chevy.
So, how is that for WAY MORE information than anyone really wanted to know?
Since mention was made to the SB Chevy, the "GENERAL RULE OF THUMB" for the Chevy is, "Safe oil pressure is 10 psi for each 1000 engine rpm." -and that statement is to be found in numerous books. (the curious question I have is, "so how about those 6, 8, & 10 thousand rpm chevys (?maybe NASCAR?) -are they really running 60, 80, and 100 psi ?? -hmmm,, I wonder,,,)
I guess from a purely mechanical engineering stand point, oil pressure by itself has essentially nothing to do with the adequate and safe lubrication of an internal combustion engine. :? HOLD ON NOW, KEEP READING :? That is purely a matter of film strength (-and film thickness, to a degree). So why do we need a certain amount of pressure then? The answer is, to always ensure the delivery of an adequate supply of oil film. (and the first parts that come to my mind is connecting rod bearings when operated at high rpm. -the various forces at play are fairly substantial !) Also engine oil plays a pretty large part in the removal of heat from almost all internal engine parts, so consequently a certain amount of continuous re-supply is necessary. And pressure certainly helps assure continuous re-supply.
Another factor that comes back to my old mind is that "minumum safe oil pressure" is also dependant on individual engine designs. SO THE BOTTOM LINE is, follow the recommendation of the engine manufacturer. I remember one other forum topic some time ago someone had quoted the specifications right out of the GM shop manual. I am sorry I don't have that book available right here now, or I would look it up and re-state it. I do seem to remember that the minumum safe pressure was higher than the SB Chevy.
So, how is that for WAY MORE information than anyone really wanted to know?
08-04-2004, 11:49 PM
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In my 1999 SSEi I ran Mobil Semi Synthetic High Mileage Formula oil with FRAM Double Gaurd and sometimes the X (forget what it is exactly, but it'* there top model in the roud canister) and changed the oil every 3-4k. I never saw oil pressure drop below 45 psi -I know this sounds odd, but I can get a picture of it at idle showing 60'ish with fresh oil and when oil change time draws near it'* dropped down to 45-50 at idle. With the engine running 4k (under load) I'd see up near 80 psi). I was very impressed with how good it was. The day I sold the car I showed the guy how clean the 2400 miles old oil was -looked like it had just been put in.
Now on my 1994 I'm a little worried. Before I parked the car last December I remember thinking "...35 psi oil pressure at idle with 206,000 miles -not bad!" Well when I started it up I noticed it was down in the 20 psi range, but I figured since the oil was old. I was correct -for about 250 miles after the fresh Mobil Semi-Syn High Mileage and FRAM DG. I had driven to work and back on Tuesday and on my way home I was noting the at 2k rpm the oil pressure guage was showing around 50-55 psi. I noticed that about 2 blocks from home. When I parked the car and was about to shut it off I noticed that at idle it was around 40-45 psi. I shut the car off and half hour later I started it up again, but then it was only at 15-20 psi. And when cruising down the freeway in OD at 2700 rpm it is only reading 20-25 psi. Cold and hot, no more than 2-3 psi difference. Check the oil and it'* full, and clean (no metal), but is that FRAM DG getting plugged, or is it a bad filter or what? The engine isn't knocking or making any unusual noises (other than the miss from the bad ICM and ECM). I'm thinking I should pick up a Purolater at Fleet Supply as well as another quart of the Mobil Semi-Syn High Mileage to top it off.
What do you guys think? Time for new main and rod bearings?
Now on my 1994 I'm a little worried. Before I parked the car last December I remember thinking "...35 psi oil pressure at idle with 206,000 miles -not bad!" Well when I started it up I noticed it was down in the 20 psi range, but I figured since the oil was old. I was correct -for about 250 miles after the fresh Mobil Semi-Syn High Mileage and FRAM DG. I had driven to work and back on Tuesday and on my way home I was noting the at 2k rpm the oil pressure guage was showing around 50-55 psi. I noticed that about 2 blocks from home. When I parked the car and was about to shut it off I noticed that at idle it was around 40-45 psi. I shut the car off and half hour later I started it up again, but then it was only at 15-20 psi.
And when cruising down the freeway in OD at 2700 rpm it is only reading 20-25 psi. Cold and hot, no more than 2-3 psi difference. Check the oil and it'* full, and clean (no metal), but is that FRAM DG getting plugged, or is it a bad filter or what? The engine isn't knocking or making any unusual noises (other than the miss from the bad ICM and ECM). I'm thinking I should pick up a Purolater at Fleet Supply as well as another quart of the Mobil Semi-Syn High Mileage to top it off.What do you guys think? Time for new main and rod bearings?