Well just installed an electric oil pressure gauge, on idle i see as low as 10 psi and sometimes lower, the oil light never comes on... Find it really weird when running i can see 40-80psi on oil cold startup is about 40psi hot idling is 10 and sometimes.... Any ideas?

 

I believe the low oil pressure is common at idle.
I usually see below 10 when idling with hot engine.
I had low idle oil pressure on my 03 MCS and have it on my 06 MCS.
I have used 5-30 and 5-40 oil with no real difference in idle oil pressure.

 

Possibly my gauge cuts off below 10 and drops to 0, i know there is at least 4psi cause the dummy light is set at 3.5 and it does not come on ....

 

Sounds normal - mine has done this since it was new.

 

Wow, that oil pressure sounds really low to me. At 62k miles my engine was averaging 22-24lbs of oil pressure at idle when hot. I tracked it hard for 2 years as well. I do use a top grade oil, RLI 5w-40HD (Renewable Lubricants Inc.) which has an excellent viscosity index & film strength.

 

Well high oil pressure on starts is common in airplanes, so I doubt a car would be any different. We have a different set of limitations for oil pressure after a cold start than warm start. I wouldn't worry about the cold vs hot idle difference.

 

First off, really? How is an airplane engine that consumes jet fuel anything like a gasoline engine of a car?


I start at about 70 and as the engine warms up, i drop to about 18 psi or so at idle

When i rev the engine and drive at 40 mph, my pressure hovers around 35-40 psi (depending on my rpm)

Does this seem reasonable? I dont want to seize my engine....

PS, im driving a 2004 Cooper S JCW Monte Carlo (if it makes a difference)

 

Seems reasonable while driving.
I would not be worried if even a little below 10 at idle when hot.

 

Er...responding to a 3+ year post and ridiculing someone who was trying to help...
P.S. SOME aircraft motors still burn avgas....but doing things like not blowing up an oil cooler on an aircraft engine on cold start by not letting it warm up before applying full power is veryvmuch like waiting for normal oil temps in a car before reving it too much for fear of blowing a seal....
To the op...YEARS AGO...
pretty normal....
One thing I have noticed...a few times I have used Non oem/Mann filters....namely carquest filters...I have seen the oil psi variations to be less pronounced.
Many folks have also noted some oils, most often Mobil 1 seems to sheer to a much thinner oil rapidly after initial use before thicking up in a few hundred miles.....

 

Funny!


And good info.