Oil Pressure...

darkstar_one

Registered User
Well i installed an electric autometer oil pressure gauge, at cold it reads maybe 60psi, but when it warms up it reads 25psi, i am using 15w50 MOBIL 1 synthetic, car runs like a champ and doesnt burn any oil..., is this normal? or maybe i should switch to 20w50? thanks.

there i corrected it, ya smart a$$
 
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your run that heavy of oil in ur SC?? i'm running 5-30 mobile 1 synthetic in mine...it's got 134k on it...but it is clean as heck inside, (zero sludge) should i go for a heavier weight oil due to the mileage..
 
Ive been running mobil1 10w30 latley on my reman motor with maybe 10k miles on it. its been quite hot and i drive the piss out of it and at idle hot i only get like 18psi pressure, but it will make it well past the 10psi per 1000rpm rule. Im a little worried on how low it is though, should i go to heavier oil maybe?
 
trife86 said:
Ive been running mobil1 10w30 latley on my reman motor with maybe 10k miles on it. its been quite hot and i drive the piss out of it and at idle hot i only get like 18psi pressure, but it will make it well past the 10psi per 1000rpm rule. Im a little worried on how low it is though, should i go to heavier oil maybe?
that seems right as long as you have a 10 psi increase per 1000 rpm. you will have less oil pressure beacuse the synthetic oil will flow much easier, thus reducing the oil pressure. personnaly i would rather have more flow with a synthetic with less pressure, than higher pressure with less flow like with a mineral oil.i run mobil 1 15w50 cuz my car has high miles, but when i rebuild it with new internals, ill switch to 5w50. or perhaps 10w60.
 
chazzwozzle stop making up oil weights, ha ha ha, im joking is there really a 10w60? or is that a typo... yeah the synthetic oil is still free flowing, doesnt really thick up, pretty kool then,
 
darkstar_one said:
chazzwozzle stop making up oil weights, ha ha ha, im joking is there really a 10w60? or is that a typo... yeah the synthetic oil is still free flowing, doesnt really thick up, pretty kool then,
of course there is 10w60. look up castrol formula rs 10w60. it is the only engine oil that is approved for the bmw M3. i figure it its good enough for an M3, then its good enough for my engine(when i rebuild it of course)actually there was a big fiasco with engine failures on the M3 prior to the specified 10w60 being required. they first required some other viscosity, something like 5w30 if im not mistaken. well that resulted in engine failures in the M3, and as a result, they turned to castrol for engine oil, thus 10w60 was developed. (yeah i was up late one night reading a bunch of useless car crap) well any ways the only place to locally purchase this high performance oil is at a BMW dealer.my local dealer sells it for 15 dollars a quart:eek: so 5 quarts is about 80 dollars so i think it will be worth it when i rebuild my engine:D
 
Synthetic oil does not cause a reduction in oil pressure. If you have 20psi at idle while running 15w50 oil then you have excessive clearances.
 
"Oil pressure is also directly related to flow volume. Synthetic oil is more uniform in molecular structure and provides less resistance to flow therefore in order to achieve the same flow volume as a petroleum oil, which has a higher frictional resistance to flow, it is possible that under some conditions, such as idling that a slightly lower oil pressure could be noticed"
this is from a book titled "motor oils and lubrication" .what is the pressure specification at idle anyways? i checked the fordtechservice.com (for which i know the username and password :D ) and i looked at the oil pressure specs for a 94-95 sc. spec is 40-60 psi @ 2500 rpm with engine at operating temp. doesnt go back to the 89-93 years but i would assume that they are spec'd for slightly lower oil pressure since the 94-95's had a higher capacity oil pump.ford actually thinks that 7 psi is good at idle, so i would think that 20 psi is good oil pressure, if your engine produces 40-60 psi at 2500rpm then who cares what the idle oil pressure is.
 
chazzwozzle said:
"Oil pressure is also directly related to flow volume. Synthetic oil is more uniform in molecular structure and provides less resistance to flow therefore in order to achieve the same flow volume as a petroleum oil, which has a higher frictional resistance to flow, it is possible that under some conditions, such as idling that a slightly lower oil pressure could be noticed"
this is from a book titled "motor oils and lubrication" .what is the pressure specification at idle anyways? i checked the fordtechservice.com (for which i know the username and password :D ) and i looked at the oil pressure specs for a 94-95 sc. spec is 40-60 psi @ 2500 rpm with engine at operating temp. doesnt go back to the 89-93 years but i would assume that they are spec'd for slightly lower oil pressure since the 94-95's had a higher capacity oil pump.ford actually thinks that 7 psi is good at idle, so i would think that 20 psi is good oil pressure, if your engine produces 40-60 psi at 2500rpm then who cares what the idle oil pressure is.
So what does it mean that at cold idle I have 80 psi and that at 2,500 rpm it generally stays there, except when the engine temps get up to 220° or hotter and then the pressure increases from 85 - 90 psi??

Ira
 
Billabong089 said:
man, I got heavy oil in mine (20w50), and I'm running 25psi around idle (hot), 150K on the motor... oh well.

you dont run 20w50 all year round do you? Im looking for the best weight to run in my SC its only out in nicer weather and in the winter ill start it up once a week and thats about it. currently i run mobile1 10w30 but i do not think that is heavy enough. i drive it like i stole it
 
I'll go with lighter oil in the winter, I just started to change my weight of the oil in the car sooo I'm not sure what I'm doing yet.
 
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