oil pressure and oil questions

jaidedeye

Member
Apr 4, 2004
627
0
16
Goldsboro nc
well i have noticed that with my U/D pulleys my car runns a little warmer especially instop and go....DUH.....well to day when i came to a light my oil pressure was sitting at 25 psi at idle wich is about 800 rpm. as soon i as i start driving again it goes to 40- 50 psi depending in cruising speed. when i first start the car in the moring it sits at 60 psi while driving it until it warms up then while driving it is between 40-50 psi....

what are normal oil pressures and should i be worried?

i use royal purple 10w-30 oil. should i use a thicker oil? my car uses no oil, no leaks or anything and does not overheat .......
 
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That is normal oil pressure. My ford service book states that the 5.0 engine oil pressure spec is at least 40 psi at 2000 rpm. If you are getting at least that your good to go.
 
Right now im running 4 quarts castrol 10w30 and 1 quart lucas oil stabalizer and i get 60 psi cold 50psi with drving and 30psi hot. These numbers are all acordding to my autometer sport comp gauges.My car has also 143,000 kilometers. Hope this helps.
 
my two cents:
the car is running slightly warmer (oil is slightly thinner at temp). and the charging system might be putting out slightly less volts at idle, which affects the electric gauge. to be sure, i might try a mechanical gauge.

good luck.
 
jaidedeye said:
i have a mechanical autometer guage
well that messed up part of my thinking. :bang:

5.0's tend to run the oil a bit hot anyhow. with elevated coolant temps, you might be thinning out a little bit more than normal. with the synthetic and pressure you have, i personally would not be worried. what coolant temps are you seeing anyhow?
good luck.
 
well i havent installed my mechnical auto meter water temp guage yet...but my stock guage runs at the second line from the bottom. if it gets warm it runs at the third line but drops down as soon as i go above 40 mph. my car actually runs cool.

i think it has something to do with my 10w-30 royal purple oil.....im might try another brand and change to 10w-40 or thicker.
 
I was shocked at how hot my oil ran when I put my oil temp gauge in. It consistently ran at 260-270F. I installed an oil cooler and knocked that down to 210F at cruise/230F in traffic.

That helped with coolant temps as well - the fans don't run as fast or for as long with the oil running cooler.

Pressure is definitely impacted with oil temp. The oil viscosity is reduced at elevated temps - i.e. - it's thinner. So as temps climb (coolant and oil), the pressures will drop for the same weight oil and the same rpm.

The pressures you're seeing aren't unreasonable. 10W30 oil will probably serve you all year long. If you wanted a bit more ease of flow when it's cold, and protection when it's hot, you could run 5W30 during the winter; and 10W40 or 15W50 during the rest of the year. The 40 or 50 weight oils won't thin out at higher temps as much as the 30 will.

The other thing to note is that the API oil specs look at oil characteristics at 0C and 100C (32F and 212F). So common oil temps seen in 5.0's without oil coolers are WAY above the numbers at which the oil is measured for characteristics. 10W30 won't get any thinner than 30 weight oil at 100C/212F. But who knows what it's doing at 260-270F.

So, jaidedeye - I think a very reasonable way to spend $120 is on Ford Racing's oil cooler. Should slightly improve your oil pressure warm, and reduce the cooling load on the radiator - as long as you mount the coil out of the airflow of the radiator.
 
Michael Yount said:
I was shocked at how hot my oil ran when I put my oil temp gauge in. It consistently ran at 260-270F. I installed an oil cooler and knocked that down to 210F at cruise/230F in traffic.

That helped with coolant temps as well - the fans don't run as fast or for as long with the oil running cooler.

Pressure is definitely impacted with oil temp. The oil viscosity is reduced at elevated temps - i.e. - it's thinner. So as temps climb (coolant and oil), the pressures will drop for the same weight oil and the same rpm.

The pressures you're seeing aren't unreasonable. 10W30 oil will probably serve you all year long. If you wanted a bit more ease of flow when it's cold, and protection when it's hot, you could run 5W30 during the winter; and 10W40 or 15W50 during the rest of the year. The 40 or 50 weight oils won't thin out at higher temps as much as the 30 will.

The other thing to note is that the API oil specs look at oil characteristics at 0C and 100C (32F and 212F). So common oil temps seen in 5.0's without oil coolers are WAY above the numbers at which the oil is measured for characteristics. 10W30 won't get any thinner than 30 weight oil at 100C/212F. But who knows what it's doing at 260-270F.

So, jaidedeye - I think a very reasonable way to spend $120 is on Ford Racing's oil cooler. Should slightly improve your oil pressure warm, and reduce the cooling load on the radiator - as long as you mount the coil out of the airflow of the radiator.
very well put, Guru. :)

IIRC, dino oil does not like to see sustained temps over ~250*F. i need to get an oil cooler, a la Guru, for the reasons you mention (got syn in it now to help combat this very thing). with the stacked coolers, does one need a thermostat on the plumbing (i thought i remembered something about stacked units not needing one??)? any tips?
 
Use an oil temp gauge with the cooler - it'll tell you whether you need a t'stat or not. With a fin-tube unit, you'll definitely need a t'stat in the colder climates. You want at least 210F or so to completely boil off condensate. My stacked plate doesn't have a t'stat and seems to do ok most of the time. I notice that if I start the car in Jan. when it's 20F outside, and immediately hit the Interstate for extended cruising, it has trouble getting above about 180F. All it takes is pulling into a service station - a minute or two of no air across the cooler - and it comes up. Once up to 210F, you can hit the Interstate and it won't drop back down. Interesting, huh? My "t'stat" is a small piece of aluminum gutter flashing that I bungee in front of the cooler - blocking part of it off in the winter. Works like a champ, it's under the car - no one can see it. Don't think I'm gonna get anymore sophisticated than that -- although I do have this temp. switch left over that closes at 220F and opens at 205F.....
 
hmm interesting, so you dont think that my current pressure readings are anything to worry about? im sure my weather in NC is similar to yours in TN. it will get down to the 20's even the teens occasionally in the winter. i have my trans cooler mounted in front of my radiator on the inside of the front bumper so there is still air circulating between them, i have no A/c so i dont have all that junk in the way either.

what if i was to get a oil filter relocation kit and oil cooler? i could actually run an extra quart of oil too right?
 
dont feel bad mine is 52 cold and 10 yes 10 whens it's fully warmed up. I have an autometer mechanical. its even been down at 8 a couple times but i changed the oil and it went up a few.It runs good so im leavin it until i get a 306 in a month or two.
 
Michael Yount said:
My "t'stat" is a small piece of aluminum gutter flashing that I bungee in front of the cooler - blocking part of it off in the winter. Works like a champ, it's under the car - no one can see it. .....
i thought you might do that (a la the 'stat' used by many Harley riders on their oil coolers (usually a pre-fabbed bag that covers the cooler's coil). sounds like a good plan Michael. thanks for the info. i was checking out coolers last night. :nice: