Oil light flickers on idle [You are my last hope!]

[Slajfoni]

The oil light starts to flicker (red) once the car has been driven for a short while (~10min).
Light immediately goes out when idle speed increases.

The car:
BMW E46, 320i (M54),
year: 2003
Miles: ~15.0000 (~240.000km)
Oil: 0w30 Castrol Edge

I took the Oil Pressure Sensor out and attached an *oil pressure gauge and here is the output:
Notice:
These are the values when the oil has reached 212°F (100°C).
The oil level is at max.

Results:

RPM	PSI / Bar
700	6 psi / 0.4 bar
800	9 psi / 0.6 bar
1000	12 psi / 0.8 bar
2000	26 psi / 1.8 bar
3000	45 psi / 3.1 bar
4000	51 psi / 3.5 bar

It is worth mentioning, when the motor is cold the oil pressure could be seen at 43psi (3bar) and dropping down with the time...
The idle speed is pending between 696 - 703 RPM according my Delphi OBD.

*link to : Oil Pressure Gage - Amazon

Here is my thoughts and questions that I need to share with someone:

• the oil is old since it has been changed 2years ago
• I have a new Oil Pressure Sensor but I'm will not replace it until I know the reason for the low pressure.
• Maybe the oil pressure gauge has not been calibrated or the O-ring on the gauges adapter that's leaking the pressure? How to test or how to know if the gauge or adapter is leaking pressure?
• I have oil leakage on the following items:
  --oil leakage on Valve Cover Gasket (seen 2 years ago)
  --oil leakage on the Oil Filter house (seen 2 years ago)
  Changing these will increase the oil pressure ?

* Change the oil from 0w30 to 0w40 ? or 10w40? I'm confused on this one since some recommends this while others don't. However, this one feels like it is the last alternative!

Here is the plan:

• Use some kind of engine oil flush additive - if the engine has been clogged! (the car is used for short distances). Then change the oil and the oil filter (0w30 Castrol)
• Inspect the old O-rings and replace them would be the best thing since I read somewhere that these can also decrease the oil pressure (I believe from 50sKid YouTube channel)

O-rings on oil filter part.nr 5
* Investigate with the endoscope camera if the suction pipe or the oil pump is clogged through the oil drain plug [IF THE IS POSSIBLE!?]

To be honest, I'm lost and sad at this moment, fearing that this could be the end for my baby :-(

I would appreciate if someone could guide me to the correct path or giving me some advice to fix this issue.
I have had this car for 15years now so it's hard to sell it! 

[dunk1]

How many miles has the oil done ? 

After doing some reading it could possibly be affected by the oil leak at the filter housing, I could be wrong but I'd be changing that o ring for sure and use a genuine one. Under £10 for OE inc VAT 

Mine failed and chucked out a lot of oil and was a right mess. 

Also came across this on Bimmer forums.

https://www.bimmerforums.com/forum/showthread.php?2170413-Low-Oil-Pressure-at-Idle-Info

 

Edited September 12, 2022 by dunk1

[Slajfoni]

On 12/09/2022 at 11:28, dunk1 said:

How many miles has the oil done ? 

After doing some reading it could possibly be affected by the oil leak at the filter housing, I could be wrong but I'd be changing that o ring for sure and use a genuine one. Under £10 for OE inc VAT 

Mine failed and chucked out a lot of oil and was a right mess. 

Also came across this on Bimmer forums.

https://www.bimmerforums.com/forum/showthread.php?2170413-Low-Oil-Pressure-at-Idle-Info

 

The car got the oil two years ago and the same oil has done 8700 miles.

[Slajfoni]

Short update: 

The struggle continues 🤕🤢🤮!
The following has been done:
Used Castrol Engine Schampoo - just for flushing all the crap inside the engine if there is anything 
Changed the oil to 0w30 Castrol Edge, oil filter and air filter
Changed the old oil filter house gasket to a brand new one
Inspected the two O-rings and they look "fine" : part nr: #5 https://www.realoem.com/bmw/enUS/showparts?id=ET15-EUR-09-2002-E46-BMW-320i&diagId=11_2201  (maybe I should changed them since they have never been replaced since year 2003 ? )  

Once the oil temperature reaches 212°F (100°C), the oil pressure drops to 6 psi / 0.4 bar 😞 

I have also replaced to another none OEM oil pressure sensor and I could not see any flickering light on the dashboard. I read somewhere that the sensor kick in once the pressure goes below 0.3 bar...  

I'm still concerned regarding the low oil pressure and I'm not using the car anymore until this issue has been fixed! 
I'm thinking of trying with another oil pressure gauge just to be sure that my mechanical oil pressure gauge is correct.

 I feel like I'm facing a "never ending" story here... 

Edited September 14, 2022 by Slajfoni

[Slajfoni]

Short update; 

I have changed to 5w40 oil (Mannol Extreme oil)   and the oilfilter to Mannfilter)

And here is the latest oil pressure that I got:



Now the question is;
Should I drive the car as usual or continue to find the issue ?
Is this normal oil pressure for the engine with my mileages ?


 

Edited September 26, 2022 by Slajfoni

[oldagem]

Hello,
i just bought my 318ci this weekend and i am having the same problem than you, red ligth is on when rpm below 1k rpm and after it red light goes out, so if you find the reason of the problem/solution let us know. 

[oldagem]

Hi man,
I don't know if you solved your problem, on my case chaging the oil to 5w40 and the oil filter and orings resolved my case fortunately, when you changed the oil filter had you changed the orings too?

[Slajfoni]

On 06/10/2022 at 21:40, oldagem said:

Hi man,
I don't know if you solved your problem, on my case chaging the oil to 5w40 and the oil filter and orings resolved my case fortunately, when you changed the oil filter had you changed the orings too?

No I did not changed the o-rings.

The oil light does not flicker anymore with the thicker oil.