Changing the oil in my baby this weekend (03 r53) with the miss's father and his curiosity got the best of him (car guy, has yet to work on a mini) as I mentioned to be careful with the spring on the inside of the housing (drain back valve). Maybe he pulled it out, maybe it popped out, but it came out. As you know, once it comes out, it will not go back in. Well we put it back as carefully as possible but now the pressure light comes on randomly at low idles, sometimes under 3, sometimes under 2. Now I've spent the entire weekend reading different forums (brain overload) and have come to two conclusions, either replace the whole housing, or try to fix it with a c-clip. Also, I've read that while the pressure light comes on, most of the time there is no fluctuation of pressure (I'm hoping this is the case). That brings me here, has anyone had any experience with this? and what would be the best option in the mean time until I can get into the shop? Currently I'm just keeping it revving above the light (in the event it is getting low pressure at low idles). If this is a common occurrence that really warrants no action other than watching my oil level, that would be nice until I can get a fix, but I'm worried that the oil may be going through the drain back valve and into somewhere where it wouldn't normally be draining back into since I have yet to see a leak and the oil level has remained the same.



Any help would be appreciated.

 

My wife's oil light was fluctuating, and would come on at idle after the oil warmed up. Turns out it's common for the oil pressure sensor on the back of the oil filter housing to leak and come through the connector. Carefully unlock the clip by pushing the red tab, then pull off the connector. If it has oil in it, replace it. I bought mine from Bavarianautosport.com for about $20. The sensor socket/wrench size is 26mm. Even if it's dry, replace it just in case it's shorting out or not sending a proper signal voltage.

The sensor is fragile, so if you tapped it while changing the filter, you could of cracked it.

 

Ah! yeah I was hoping it would be an easy fix, but as most things it is not. I think I am just going to replace the whole housing with the updated mod. Thanks for the help!!

 

Typically, I'm a proponent of the ingenious fix for pennies vs. hundreds, but in this case, I would recommend just spending the money on a new housing: lock, stock and barrel. It'll be cheap insurance in the long run, if you're planning to keep the car for a while.