ok fellas,

have a question, quick one.
I have a mild 350 in my Velle, I noticed that my PSI was at around 15 PSI at idle last night on my way home, it goes up to about 40 PSI when running, I been running 10-40 Castrol on it, isnt the PSI to low for it?? do i need to bump it up to a 20-50 weight?? or why is my PSI so low? or is it normal??

thanks :D

15 psi is a little low, but not dangerously low. You might get a little higher pressure by going to the 20-50 and it certainly won't be a problem going to the higher viscocity in your climate. I'd give it a try.

what is the normal PSI that i am suppose to be running?? if its not the oil, what else could it be??

if its not the oil, what else could it be??


I'm guessing a loose or worn out engine. My current oil pressure is almost exactly what yours is at idle and going down the road, and I was told loose clearences in the botton end are usually to blame, especially in a really old engine.
That's one of the reasons I'm building a 383 for it right now.

*PS- I tried 20w-50 as well, no change for me.

Where is the PSI suppose to be at?? idle and running??

15 and 45 are fine. stock Chevy cruise oil pressure is usually around 40-45 PSI. hot idle low rpm pressure, anything over 10 is fine. For some reason guys get all obsessed with this, it's a waste of time.

Tom,
so should i change from 10/40 to 20/50?? or just leave it alone??

ok fellas,

have a question, quick one.
I have a mild 350 in my Velle, I noticed that my PSI was at around 15 PSI at idle last night on my way home, it goes up to about 40 PSI when running, I been running 10-40 Castrol on it, isnt the PSI to low for it?? do i need to bump it up to a 20-50 weight?? or why is my PSI so low? or is it normal??

thanks :D
10 psi for every 1000 rpm increase should be safe and not steal HP.60 psi at 6 grand.Lighter weight oil lubes quicker on cold starts reducing wear and tear.This a general statement.Should be safe for street engines in varying climates.Hope this helps.George.

As stated Ralph. 10psi per 1000rpm is normal for a stock oil pump. The 10-40 is fine.

I agree with Tom, dont worry about it. had a well worn TPI (124k miles) and a brand bew (yearsago) carbed 350. Both when good and warm would hover around 15 or so at idle. Drive and enjoy.

I think GM claims the SBC can be run as low as 6 psi before any damage occurs..When my TPI started to blow a head gasket I would occasionally see 9 lbs at idle whn it would get hot. , lol. Still blasted it at the track with no problems.

10lbs per 1000RPM is for racing engines, you don't necessarily need that much on a street engine.

I wouldn't worry about the hot idle pressure until it gets down to 10 or less. The normal GM idiot light sender triggers at 5 lbs or less.

Going down the road I wouldn't sweat anything over 40psi.

All this assumes it's consistent, if there's a change in the cruise pressure, like it's always been 50 but this weekend it dropped to 40, that needs looked at.

Cool, Cause at idle when it is hot, it hovers between 15-20 psi, and running it is around 40psi, thanks for all the feed back fellas :thumbsup: again, this is an awesome forum, lots of good help :thumbsup:

I was thinking next oil change, to bump it up to a 20-50 weight, or maybe try the 15-40 weight from Rotella or i shouldnt worry about it and keep feeding her 10-40 weight?

Oops didnt read the thread, i am going to her at 10-40 weight :thumbsup:

Thanks again fellas!! :D

Cool, Cause at idle when it is hot, it hovers between 15-20 psi, and running it is around 40psi, thanks for all the feed back fellas :thumbsup: again, this is an awesome forum, lots of good help :thumbsup:


Sounds right about the same PSI that my 350 idles and runs at. I've been using Castrol 10W-40 the last 2 years.

yeah i was using for the last year Castrol 10-30, but saw my PSI dip down from normal 20PSI at idle to around 12PSI, so i switched to Castrol 10-40, and now it stays between 16 - 20 PSI at idle, when it is running, its around 38-42 PSI, that is when its HOT. I never seen it go over 42 PSI, only when it is cold at start up.