I did an oil temperature and oil pressure gauge on mine.
With the temperature sensor I drilled and tapped the oil filter housing so it actually reads the temp of hot flowing oil, rather than putting it in the sump plug.
The oil pressure sensor is fitted in the side of the filter housing,
There is already the standard BMW one in there, which you remove and fit the new sender using a tee piece, then refit the original back in the end of the tee. See last photo.
Easier if you take the filter housing off which can be done without having to remove the Inlet manifold, Then you can also replace the filter housing gasket which will fail at some point anyway.
See below from my thread:
There is already a temperature sensor and oil pressure sensor in the housing,
The temperature is the one on the front face at the top, and the pressure sensor is on the side of the housing that faces the rear of the car.
The new oil pressure sensor will just fit into a tee, branched off the side of the oil filter housing.
However with the oil temperature, if that's fitted using a tee, it means it sits in colder static oil, and its much the same problem if it's fitted in place of the sump plug, so it reads colder than normal so I thought I would experiment
This involved buying a cheap (£15) filter housing:
and after removing a side blanking plug, being able to see where the original temperature sensor is ,as below:
The tip of my finger below shows the route that oil exits the housing from the filter bowl on the right:
Nice flat gasket also:
but it gave me a pointer as to where would be best placed to fit the additional temperature sensor so it's in flowing oil in that particular chamber.
So I drilled and tapped a 1/8 bsp hole to mount it...
Tested and all working:
Be aware that the oil pressure sensor has to be angled a certain way otherwise it fouls on the inlet manifold or block.
In my last photo where the sensor head canister was upwards, it fouled.
So it has now been rotated anticlockwise about 40 degrees so it is facing away from the block.
You can see the original sensors have been refitted, temperature in original location and the pressure at the end of the tee piece.
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