|
PFitto, a few questions first. Who performed the oil change? Was it a dealer, or independent BMW mechanic, you, or jiffy lube? The reason I ask is are you sure whomever changed the oil knew what they were doing with respect to changing the oil in an E90 and how many quarts they refilled the engine with?
The oil change procedure is very simple, but because the engine doesn't have a dipstick, some mechanics unfamiliar with the E90 can't deal with it and don't add the proper amount of oil. When you change the oil, it all drains out with about 10 ounces or so left in the oil filter housing. The oil in the housing is quite visible when you open the housing and remove the oil filter cartridge. The oil in filter housing needs to be removed also, by either soaking it up with a rag, or sucking it out with a liquid extractor (most auto shops have one). Once the oil is drained and a new filter installed in the filter housing all that is needed is to re-fill the engine with 7 quarts of oil. There is no guessing about the amount of oil to add; it is 7 quarts. Most mechanics are used to a traditional oil change process which is to add 1/2 quart less oil than the engine takes, run the engine for a few minutes, then check the level with the dipstick and add more oil to get the dipstick reading to "full"; which is why, if they are not familiar with the E90, the lack of a dipstick is troublesome to them.
Unless your engine has a major oil leak, which you'd probably notice by now with the smell of burning oil, the engine is not low enough on oil to cause a low oil pressure condition. The car will indicate a low oil pressure condition and make it obvious to shut off the motor, so you needn't worry about damaging the engine under your current situation. The lubrication system in the N52 engine in the E90 is sophisticated because it uses a constant velocity oil pump to maintain a constant oil pressure and flow, as the VANOS/valvetronic system requires unvarying pressure to function properly.
I recommend that if you can't determine how much oil was initially added in the engine at the last oil change, take the car to a BMW mechanic who knows how to change the oil in the dipstick-less E90 and get the oil changed properly. This would be the cheapest way to evaluate the problem. Make sure you ask the mechanic to measure the quantity of the drained oil to help determine if the sensor is reading correctly. Usually the sensor goes bad and doesn't read at all. The sensor is not hard to replace and costs about $160. I’ve checked my drained oil level several times and the sensor has been very accurate in its reading.
|