high oil pressure

[r34 gtr]

and i mean really high! im pegging my autometer gauge at ~3000 rpm in all gears while hot. cold it just stays between 75 and 100lbs. at idle hot im reading 25-45lbs. any ideas? my oil pressure seemed fine until yesterday. the car sounds like it runs fine, though it may be a little down on power and it has a little bit of a rough idle. timing is 15 degrees btdc, checked it and the plugs yesterday.

the car is back together and running fairly well by the way, it just needs a little more work before we take it to a dyno and tune it.

- tim

[float_6969]

holy crap! are you sure the gauge is reading correctly? At NOT, I'm at about 50psi of oil pressure at 3K. Hot idle will be as low 15-20 psi. But I'm running mobil 1 0-40w. I remember it being higher when I was using non-syn 10-40w last year. I'll be changing up to Amsoil 20-50w in about a month. I expect it to go back up at that point.

[Winona]

i have the exact opposite problem.... so i was leaking oil out of my oil pressure sending unit, out of the bottom so i tighten down the nut on the bottom i was running at about 25 psi at idle and about 50 psi at 3k, now after i tightened it i never get above 20 psi, is there way i could have blocked off the oil flow or just screwed up the sender?

[boost_boy]

If you're idling at or around 800-850rpm, your pressure can be as low 12psi and it's perfectly normal. If you're idling at 25psi, it's a bit high for 800rpm idle but it's still okay. When the engine is cold, some pressures can get as high as 100psi when you rev and this is okay. But when the car is hot, it should not be that high. Normal range is from 45-60psi with normal driving and maybe a wee bit of aggression on the throttle.

Dee

[nismoplsr]

Something recently happened to my autometer gauge and or sending unit. When the car is off i read 80psi of oil pressure. Check the gauge and sending units.

[Winona]

i mean some times now it barely makes it off the 0 psi line. and when i rev it it barely moves

[boost_boy]

i mean some times now it barely makes it off the 0 psi line. and when i rev it it barely moves

I mean, if it's really that low, I would be looking at atleast changing the pump. How is the pressure when you're driving? I drove around on crappy oil pressure in the car I just got done completing and ended-up having to tear it all back apart, change all bearings and yet another new oil pump. Now she runs great with great oil presure as well. Thin oil can also cause low idle oil pressure as well.

Dee

[Winona]

the pressure when i drive around now is really low never getting above 20psi... i was thinking it could be the oil pump.. but this happened right after i tighened down the pressure sending unit

[float_6969]

I would run down to your local pool store or hardware store and get a regular pressure gauge. Unscrew your sending unit and thread the gauge into it. Somehow you'll have to safely run the motor and be able to look at the gauge, but if it reads low as well, it's possible that the pump is bad and will need replaced ASAP.

I wonder what the opening pressure for the stock sending unit it?

[r34 gtr]

im running the same oil i have been for nearly 5 years, castrol gtx 10w40. im thinking its probably the gauge as the car sounds normal, but im still not sure. the gauge reads so linearly and everything its just hard to say it isnt working properly.

i was reading 50lbs at 3500 while hot on sunday, and then i drove it 250 miles and now its reading sooooo high. i just rebuilt the engine, so im guessing that might have something to do with it.

- Tim

[Fenvy]

i'll give my input as well for record

I am running redline 10w40-after done warming u the car, around 76C in water temp, my oil pressure is around 200kpa (29psi)-after drving in moderate temp, around 83C in water temp, my oil pressure is above 150kpa (22psi)-in a hot day drive or stuck in traffic idle, around 90~105C in water temp, my oil pressure can get as low as 90kpa (13psi)-while driving, boosting or whatever, it can get over 500, 600kpa