2.7T APB - oil system - functionality - parts, drawing, schematic

[vtraudt]

Trying to understand how the lubrication of the 2.7T APB engine works.
Obvious that the oil enters the pump through the submerged filter screen in the bottom of the pump.



It appears there is one (pressurized) outlet here:


Then one outlet or inlet that just 'flanges' to the upper oil pan:


There is a spring loaded ball valve; I assume that is the internal pressure relieve valve:



I haven't open up the actual pump (vane type?) yet.

Is a function description available? Maybe with a schematic?
Of the pump itself.
And then 'where does it go from there'? And what other elements are involved (we have the pressure switch at the oil filter housing, the oil filter, the various lubrication points/channels, the oil level/temperature sensor (bottom of oil pan).

Trying to understand what can cause low oil pressure (aside from 'bad engine' (like bearings, etc.)).

[Monty23]

I posted this in your other thread:

[vtraudt]

I posted this in your other thread:

Thanks, will take a close look.
I have to check my settings, not getting email notifications.

[vtraudt]

Very helpful, thanks.

Deciphering:
Primary pump outlet is going to oil filter/cooler. This line has an oil pressure relief valve (anybody know the pressure setting for the relief valve?).
Not sure how this works/interacts with the bypass valve/filter in the oil filter itself?

The return goes to the main supply line, which has a return path (back to the internal oil pump suction side), which includes the oil pressure control valve (ditto: setting?)

Since I am troubleshooting a low oil pressure (not engine caused) situation, what possible changes (from good pressure to low pressure, during upper/lower oil pan removal and reinstall) may cause the low oil pressure situation.

[Monty23]

Did you verify the low oil pressure with a pressure gauge?

[vtraudt]

Did you verify the low oil pressure with a pressure gauge?

No.
Blinking red oil can and engine noise (markedly different from before the oil pan removal). Without the noise change, I would look into (had before) erratic oil pressure switch/warning, that are NOT real low pressure situations.

Thinking about backflushing the system (backwards flush).

[vtraudt]

One thing that changed (before/after): when removing the oil cooler, I cracked the plastic element that sits under the oil cooler.
I will remove the cooler later this morning to inspect again and take photo (no idea what the function is).

[vtraudt]

One thing that changed (before/after): when removing the oil cooler, I cracked the plastic element that sits under the oil cooler.
I will remove the cooler later this morning to inspect again and take photo (no idea what the function is).

this thing:

https://c1552172.ssl.cf0.rackcdn.com/83716_x800.jpg

[vtraudt]

this thing

Oil Cooler Seal
Seals the connection between the oil cooler and the oil sump

Could this lead to low oil pressure?
In any case, will look for quick replacement right away now.

[Monty23]

You should have verified the oil pressure with a gauge, the top end on these cars can get noisy for many reasons, such as a CCT pad disintegrating among other things. Did you find any suspect o rings from the oil supply plumbing? Items 8 and 18 below: