what causes low oil pressure?

[Scott W]

my car's oil pressure seems to drop when the engine gets warm. It usually dips pretty low at idle and then bumps back up when I give it gas. I've replace the sender. the car has over 300,000kms.

How low can your oil pressure drop and still be safe?

 

[fivespeedsteed]

the oil passing through the same passages over time. like a river carves a canyon or something like that. thats what i hear, over time i guess thats why it gets less and less

 

[ShortThrow50]

sounds to me like the oil pump itself s goin bad

 

[putnam88]

well i doubt it is oil pump those last for ever unless ur have dirt or sludge in ur motor, but usual is ur bearing clearances on any of ur internals main, journal rod, and cam bearing just the slightest bit off with drop ur pressure way down, and it goes back up when u get on the gas cause u are speeding up the oil pump moving more oil making up for lost pressure make sense

-Steven

 

[Foxfan88]

as bearing tolerences increase over time due to wear and tear the same volume of oil flow wont be able to cause the pressure buildup that it could before.

 

[allballsmustang]

when you say it drops low at idle, how low is it?

 

[GTOreturns]

Oil pressure is oil pressure is oil pressure! You either got it or you don't!

 

[RYC CUKR]

As others have said over time bearing clearances open up a little bit, especially 300,000 km, and can cause the oil pressure to drop.

Here is what I like to see for oil pressure #s. I like at least 20 psi at hot idle and then a 10 psi increase for every 1000 rpm increase. You could probably get away with 10 psi at hot idle but that is a little low for my liking. The rule of thumb is 10 psi for every 1000 rpm.

 

[iwashmycar]

10...damn. mine stays at like 55ish all the time....hmm

 

[fivespeedsteed]

mine is about on point. i got about 20 or so hot idle, probably like 22-24, and then gets up there once i start goin.

 

[Scott W]

mine is about 1/4. I live in canada and I don't have acual numerical markings on my gauge, just a bunch of ticks, but its about 1/4 from the bottom.

 

[superspec]

mine is the same way, usually between the A and L at hot idle. but while driving its up in the 3/4 range on the stock gauge. in 5th gear doing 30-35mph though itll get back in the lower 1/4 area.

 

[Jaswir]

mine at startup cold is about 55 and hot idle it sits at 26-27 and increase as i hit the gas 30-40's