Low Oil Pressure

[Twizted_3KGT]

Whenever my Formula warms up the oil pressure drops to about 10-15 on the gauge, I would imagine it's supposed to be arond 30-45 at all times, what could be causing this, just age?

[Mr. Luos]

Mine drops once it warms up as well.

The oils thins out, and therefore there is less pressure. Mine normally drops 8-10 PSI once warm.

[CreepingDeath94]

If you're real worried about, try running the next higher grade oil, like 10w30 if your running 5w30.

[Twizted_3KGT]

Well i'm running 10w-30 high mileage w/ some additive stuff (8 cylinder treatment stuff supposedly seals cylinder walls)...I was debating running 20W-50, I know that's not what the engine is designed for, but I have interchanged 10W-30 and 20W-50 in my 3000GT with the only result being a difference in oil pressure (and I stopped burning oil when I went thicker, it calls for the 20W-50).

Well i'm kinda relieved that someone else has that low of pressure. Does anyone know of any bad side effects of running 20W-50?

[CreepingDeath94]

Most of the newer engines can't run that thick of an oil because the clearances are so tight that anything more than the 5w30 or 10w30 may actually hurt the engine. In other words, the oil can't get into the needed areas and its like its running with no oil. Anyway, your '88 should be fine running 20w50, most chevy's have fairly loose clearances so you'll be fine.

[Mr. Luos]

Thinking about it.....mine only gets down to 30 PSI when warm. And I run 5w-30 Mobil 1.
When cold, it is closer to 42-45 PSI.

Oil pump might be on it's way man. If you have never seen pressure that low, look into it.

[Twizted_3KGT]

lol oh great thought I was ok for a second there, funny the oil pump never crossed my mind once. Is there anything besides the pump that would cause low pressure?? or would that only be if there was oil leaking?? I hope it's something as simple as the oil pump.

[Mr. Luos]

What does it get to when the motor is spinning higher than idle?

[Twizted_3KGT]

At high rpm's 15-25 at most, and I think it used to stay around 30 but its been so long since I last drove the car I don't remember. But only once its warm, when its cold it stays around 30.

[Mr. Luos]

I wold recommend a thicker oil. See if that helps. If not, consider the pump.

[MagicRat]

Originally Posted by Twizted_3KGT

At high rpm's 15-25 at most, and I think it used to stay around 30 but its been so long since I last drove the car I don't remember. But only once its warm, when its cold it stays around 30.

10 to 15 at hot idle is a bit low but okay. Even if the pump is a bit worn, it should jump to 30 or more if the revs come up. If it stays low at higher revs you definitely have a problem, it may just be a bad oil pressure relief spring, as opposed to a bad pump.

Also, if 20w-50 is a bit thick, consider 15w-40, intended for diesels. This oil has a better anti -wear additive package than gasoline engine oil.
But these additives will reduce the effectiveness of the cat converter over time if your engine is burning a bit of oil. This is why this additive package is not put in oil for gasoline engine oils.

[Tim81ta]

Your oil pump screen and filter should have bypass valves for cold starting, they allow the cold oil to flow through the engine. Without these bypass valves, the oil would not flow through these areas. So naturally your oil press will be higher at a cold temperature then warm. And yes when warm your oil does thin out, but if you read your viscosity, you can see how it will act.

I would also not venture on running thicker oil then manufacture recommended.. There is a reason that the manufacture's recommend different oils for different climates.

My last note on oil pressure, it's really volume that your oil pump creates, and what you should be worried about. Check your owners manual for the oil pressure limits on your engine.

[Twizted_3KGT]

Hmm, well I don't really want to try thicker oil just because that would be going around the problem instead of fixing it. And I think it would probably be better to replace the whole pump rather than trying to fix a part of it, especially since the car's old and it'd be good for it even if its not the problem. I've already replaced most everything on the engine already, theres only a few parts left to go.

Oh could it have anything to do with the timing chain/water pump in anyway? I can't think of how it could but I know thats the major service thats overdue.