Oil light on at startup

[Billw]

After a couple of years of ownership finally have my 72 Euro E3 sorted out well enough to drive regularly. Noticed that the oil light is on for a about 3-4 seconds after start when car has been sitting for more than a few hours. Don't recall this previously occurring. From what I have read this may be due to a faulty check valve in the filter housing. The current filter housing is the top bolt canister style, so I assume it was upgraded at some point as it looks like ones advertised on the net out of E23's and E28's. I believe the block to be original and rebuilt at some point; head is from an 81.
My questions would be;
Is the check valve a replaceable item?
Should I just buy a used housing off the net and hope the check valve is good?
Read somewhere there is a hole that needs to be plugged with the newer housing but not sure what to check for. This may have already been done in this case.
Don't know that any damage would occur, as not under load, if not addressed but just don't like the light on with a running engine.

Not well versed in BMW's but learning. Thanks, Bill

 

[HB Chris]

Three to four seconds sounds excellent to me if it has sat for a bit.

 

[gwittman]

Yes, It seems the pressure sensor is at the end of the oiling system, and you are getting oil to the bearings before the oil light goes out.

 

[sfdon]

I think you should post a picture of what filter house and you’re using

 

[lip277]

The oil light on the M90 that Don installed says illuminated for about 3 to 5 seconds when I start the car (3 seconds if the car is warm, a bit longer when cold).
I use 15W50 Mob 1 oil. I have a pressure gauge and it starts to come to life right when the light goes out (FWIW).

 

[Billw]

Don
Here are pictures of current setup. Let me know your thoughts.
Oil is 20W50. Car is kept in my shop so always 65 degrees or above.

To everyone else thanks for your input seems I am not alone.

 

[HB Chris]

Bill, You have the later top bolt housing which I prefer as it makes oil changes much easier.

 

[Billw]

Found these diagrams of the later style and early filter housings.
Note that on the later they added the Return flow inhibiting valve
- opening pressure = 0.1 ±0.05 bar (1.4 ±0.7 psi). Marked #4

I believe the reason for the update was to stop oil from the block and head that is higher than the top of the filter canister to back flow through the filter and then seep past the oil pump (if it has some ware) and drain back into the pan. The equivalent of wet sumping on dry sump motors as experienced on most old motorcycles. Because the filter canister is full it takes less time for the pressure to build then after an oil change. BMW probably felt that this eventually might shorten the lifespan of the motor and made the update. My rational anyway.

The housing is easy to access and hopefully can find a good used one on the net. Will let you know the results.

 

[sfdon]

What you have installed is the best one as far as I’m concerned.
Nothing to change except the hardware the next time you change your oil