Oil Sensor

speed12

Member
Evening All,

Ever since I bought by Z4 about a year ago, I have had an intermitant orange oil warning light pop up on the dash every time I switch off. I used to get it sometimes during driving, but that was when the oil was just above the minimum mark on the dip stick.
Now I check it most weeks and its always in the middle of the dipstick region.

However I stil get this damn oil symbol most times after I switch her off. I keep a close eye on the engine temperature and its always fine, the engine is also smooth so I dont think there is an oil pressure issue.

I suspect it is a dodgy oil sensor. Now I plan to get it serviced within the next 4 weeks at a BMW garage, (Though I will do the brake fluid myself). Do I get them to run a diagnostics (costing lots) or do I change the oil sensor myself?

Does anyone know where the oil sensor is located on a 3.0i? and how I go about changing it? I presume its on the sump somwhere, so changing it when the oil is drained would be the best route?

Kind regards
 
I know this thread is 35 years old, but did you ever get this figured out? I just started having the orange light pop up when I turn off the car, although it only seems to be happening with cold temps.
 
Looks like he traded up for a newer model because 2008s do not have dipsticks. :D

Temperature related erraticness does point to sensor issue. If you're sure the level is correct, you have a dipstick, I'd be inclined to ignore it until the warning persisted. Dipsticks are eminently reliable. If no dipstick, how do you know if it's right or not? :headbang:
 
bcworkz, I have a 2005 2.5 with a dipstick. The oil level is consistently centered between the block on the stick, so it is where it is supposed to be. I guess I will see how it goes when it warms up and just not worry about it until then, although it is annoying.
 
You could try putting a fraction of a litre in to bring the level up to the top of the block...no more though! It may be enough to get rid of the warning. It is quite annoying, but not nearly as bad as on all the time.
 
Yeah, it definitely could be worse. I'll add a quarter of a litre or so and see if it helps. One more question, does it matter what brand of synthetic oil I use? I don't know the exact brand the shop used, but I know they used 5w30, can I just get the Mobile 1 5w30 even if they used a different brand of synthetic?
 
The oil pressure (I believe) is taken from the oil level sensor on the bottom of the sump.

Changing it is easy:

Drain Oil as per normal
Remove the metal undertray completely (6 bolts, possibly 17mm)

Then you'll see it, three (possibly 10, possibly 13mm bolts and a plug.

Unplug said plug, remove bolts, pull it out, fit new one. Reverse process.

Hope that helps.
 
clintman17 said:
One more question, does it matter what brand of synthetic oil I use? I don't know the exact brand the shop used, but I know they used 5w30, can I just get the Mobile 1 5w30 even if they used a different brand of synthetic?
For a quarter litre that'll be fine. Your shop should have used an oil with BMW LL3 rating. Maybe it's different in your area, but here (the Rockies) BMW is the only readily available source of the stuff.

RJS-Z4 is correct, changing the sensor is pretty easy. The main reason I said I'd just ignore it is it's not cheap (~$140) and it's a silly way to monitor oil level IMO. It wouldn't measure pressure though, the sump is not under pressure. That sensor is actually behind the filter housing. If the annoyance factor makes the replacement cost worth it, then by all means do it. You may want to at least wait until you're due for an oil change. It's up to you, not a big deal no matter which way you go.
 
Thanks for the advice. I put a little over a quarter of a litre in and it seemed to solve the problem. So, we will see what happens, but, for now all is well.
 
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