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Oil level sensor DIY fit

168K views 92 replies 55 participants last post by  Alex323Ci 
#1 ·
Hi. I posted on the general e46 board and the problem with my 2001 e46 325i SE saloon was diagnosed as a faulty oil level sensor. From my and other posts this seems to be a fairly common probblem.
Can anyone provide any info on how defficult it is to DIY fit a new sensor ? My dealer wants over 300 dollars for the job, so a DIY effort is quite appealing. Does anyone have and photos of a sendor unit and where it is located ? Can it be done using standard drive-on car ramps ? Thanks
 
#41 ·
Does anyone know for certain the torque for the 3 hex nuts for the oil level sensor?? It's not listed in the Bentley manual, nor exact specs in the install pdf.
 
#42 ·
#46 ·
I followed the TS version I have. It said 22Nm (~15ftlb) and I stripped one of the bolts out. I'd use a 1/4" wrench and do it nice and tight. I only have 2 well torqued bolts holding mine and get no oil loss - lol.

This is a small thread. I want to say 5 or 6mm and as such the torque should be more in the lbfin rather than ftlb level.
 
#47 ·
#50 ·
When mine failed the only indication was the amber light stayed on for a short duration on startup and then clears. This in combination with a dipstick showing you actually do have oil lets you know you have this problem. I don't think this would throw any codes as the sensor failure seems to indicate loss of oil is the issue (i.e. not an issue with the car itself, just fluids).

If you have a continuous check engine light I suspect you will have some fault codes when scanned. In my experience these are 9 times out of 10 associated with the emission system.

If you search in the threads you'll find you can scan the codes in your vehicle without a reader. I have done this and it seems to work ok.

I did buy a code reader as I have several vehicles which don't have this capability. If you did decide to buy one you can probably get one shipped from the US for around the cost of that 1 scan. I bought one for $60 if I remember correctly.
 
#52 ·
^ I have had no leaks using the torque setting bmw gave.
 
#54 ·
Just completed the oil sensor repair. Not complicated. A couple notes based on other people's posts...

The job can easily be done with the car on ramps. I agree completely with those who've said that if you can change your own oil on an E46, you can absolutely perform this repair.

The sensor cost about $96 from Bavarian Autosport after a price match to AutohausAZ.com and it came with its own gasket. The old sensor itself was very easy to remove once the metal plate was off the car and the oil was drained. The Hella sensor that I installed appeared to have come off the same assembly line as the Hella/BMW part that originally came on the car, except that the BMW logo and part number had been removed with a grinding tool (probably a BMW stipulation to Hella for aftermarket sales).

I see no reason at all to replace the 8 bolts that hold the metal plate covering the oil pan. The bolts were not difficult to remove with a 17mm socket on the end of a 2 foot breaker bar, although getting them back in required some squirming since some of them go in at an angle, it's a bit tough to start the bolts by hand, and you have to use one arm to hold the plate up in the air, but it just takes some time and patience to get everything to line up. If you want to drive the car for a few days without the metal plate attached to make sure you have no leaks, I don't think that would be a problem unless you run over a log or something and rip the oil pan off the engine; yes there is probably a structural rigidity aspect to the pan, but again, a few days without it probably wouldn't hurt.

When I did the job, I scrubbed both sides of the metal plate and the plastic cover on the bottom of the engine compartment (which didn't need to be removed to change the sensor) so if there are leaks down the road, I'll know where they are.
 
#55 ·
If you want to drive the car for a few days without the metal plate attached to make sure you have no leaks, I don't think that would be a problem unless you run over a log or something and rip the oil pan off the engine; yes there is probably a structural rigidity aspect to the pan, but again, a few days without it probably wouldn't hurt.
I assume you're talking about the chassis stiffener brace that's present on coupes (and maybe on convertibles too?). The Bentley manual specifically says not to drive without this piece installed because the chassis will flex too much without it and you risk damaging the frame. With the rough roads we have here in New England I certainly wouldn't try it.
 
#57 ·
You absolutely need to replace the 8 bolts that hold the chassis stiffener plate. They're what's known as "torque-to-yield". Once you've torqued them the first time, their metallurgical properties change. An ordinary bolt stretches a little when you torque it to spec. When you remove it, it springs back to its original shape. "Torque to yield" means that in tightening the bolt for the first time, you've exceeded the plastic deformation point or "yield point" of the metal--<i>i.e.</i> the point where, once exceeded, it will no longer "spring back" to its original shape. Once you've done that once, it doesn't take too much more additional force to exceed the <i>tensile</i> point of the bolt--the point where it snaps under tension.

I should point out that the bolt will be placed under even more tension when the car is in operation, particularly if it's being driven hard.

Now, you could get lucky, and those bolts would never break. I imagine most of them never do. But do you really want to be the test case for the guy who hit a really bad pothole and had the bolts holding that plate break? Or do you want them to break while doing a drift at a track day? The bolts are what, a couple bucks each? Cheap insurance.
 
#61 ·
The dealership never put my underguard back after some warranty work was done. Months later, I did my oil level sensor and saw the underguard missing - WTF! Needless to say I don't go to the dealership - warranty or not! No damage to my undercarriage in years! Like someone said - it's just a piece of plastic.
The plastic splash shield is not a structural component... and is not fastened with hefty TTY bolts. The metal plate behind it is.

Class of '03 and '07 ftl.

:tsk:
 
#60 ·
The dealership never put my underguard back after some warranty work was done. Months later, I did my oil level sensor and saw the underguard missing - WTF! Needless to say I don't go to the dealership - warranty or not! No damage to my undercarriage in years! Like someone said - it's just a piece of plastic.
 
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