Apex wrote: Mon Jul 06, 2020 6:33 pm
G'day Fellow Posters
I've read with interest the various posts regarding low oil pressure. I've just installed an Autometer oil pressure gauge. The oil warning light comes on when the car has stopped, and almost stopped (in low gear), the gauge then showing from about 5 - 8 p.s.i. Is this something to worry about, as there is still minimal oil circulation? During normal road speeds the pressure fluctuates between 24 and 28 p.s.i., which to me seems O.K. My engine is, I think, a little worn, though not blowing smoke or leaking oil. Has anybody had similar readings? Many thanks in anticipation.
Hi Mr Apex,
Its been a very long time since I ran a grey engine (if that's what you have) but I do remember the idiot light coming on and off when stationary after a run eg traffic lights etc.
Couldn't tell you the pressure though, but it sounds right what you are quoting.
Sounds like oil pressure is down a little, but not bad. They idle at 10psi, and the idiot light comes on at 6-10psi. As long as it is "blipping" on or flickering, then probably OK. They come up to 27-31 at 1200rpm, and will do 40psi before the relief valve lifts.
More a worry if you run the oil level low. Stop suddenly, and the light will come on as the sump baffling is pretty agricultural. Do something stupid like fang it hard around a roundabout with low oil and the light will come on at full-noise. Not good.
Has anyone seen Rosco?
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
G'day Gents
Thanks for the replies. I neglected to mention that the oil pressure light comes on ONLY when hot (after 10 miles), and it doesn't always flicker, mostly gives a steady glow, but goes out when revved or driven into 2nd gear. It seems to be getting slightly worse since I changed the oil last week, but sump is nearly up to 'full' mark on dipstick. I used mostly Penrite Classic Light 20W 60, but with that I used up a little Gulf Western 20W 50 oil that I had. That was all I did differently from other oil changes.
Apex wrote: Tue Jul 07, 2020 5:23 pmIt seems to be getting slightly worse since I changed the oil last week, but sump is nearly up to 'full' mark on dipstick. I used mostly Penrite Classic Light 20W 60, but with that I used up a little Gulf Western 20W 50 oil that I had.
That is likely part of the reason why the oil pressure issue has gotten a tad worse. The change from 60 to 50 means the engine oil will get "thinner" earlier (at 50C instead of 60C). Running the 60C alone will help, though you are pretty much at the top-end of "thick oils".
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
G'day all, thought I'd let you know of developments with the low oil pressure when engine is hot - now happening at about 7 or 8 miles (was 10 miles) so getting worse. My mechanic pulled apart the oil pump, and though the relief valve and gear were not too bad, the relief valve spring was quite a bit shorter than the new one, so it was replaced. The problem still exists, however!! In light of this, he strongly recommended that I start using Penrite HPR40 (25W70) oil instead of the 20W60 that's now in the engine. But he did tell me that the engine seems in good condition, and it's not blowing smoke, though he can't see any other alternative to getting someone to rebuild the motor if the thicker oil doesn't work. So that's where I'm up to. Cheers!
Doesn't take a lot of wear on the gears to drop pressure so if you take the pump out might as well put a new set of rates gears into it at same time
Apex wrote: Wed Aug 12, 2020 5:44 pm
G'day all, thought I'd let you know of developments with the low oil pressure when engine is hot - now happening at about 7 or 8 miles (was 10 miles) so getting worse. My mechanic pulled apart the oil pump, and though the relief valve and gear were not too bad, the relief valve spring was quite a bit shorter than the new one, so it was replaced. The problem still exists, however!! In light of this, he strongly recommended that I start using Penrite HPR40 (25W70) oil instead of the 20W60 that's now in the engine. But he did tell me that the engine seems in good condition, and it's not blowing smoke, though he can't see any other alternative to getting someone to rebuild the motor if the thicker oil doesn't work. So that's where I'm up to. Cheers!
I actually did that too; the gears I replaced had minimal wear. The relief valve, whilst seeming a little "burnt" (dark in colour) still seemed OK, but was replaced anyway. The problem continues to worsen, so after a trial of a few months with 25W70, I'll probably have the engine rebuilt, as EK283 suggested.
Last edited by Apex on Sat Aug 15, 2020 7:17 pm, edited 6 times in total.
