RE: next question for the newbie

["Fadeev, Alex" <Alex.Fadeev@xxxxxxx>]

Mark Tetrault <tetrault@domain.elided> asks:
>
> I'm trying to get used to this 525i so bear with me. 
> What would be considered a normal oil consumption for a 1990 525i with
> 100k k miles on the odometer?  I drive 85% highway speeds (75mph+)

That would be a 525i with an M20 engine, right?
For older engines, BMW used to advertise maximum normal oil consumption of 1
quart/liter per 1000 miles.
For newer cars, BMW increased the 'normal' oil consumption level up to 1
quart/liter per 600 miles.

> I added one quart yesterday with 2600 miles since the last oil change
> when the low oil level warning came on in the instrument cluster. Now
> everytime I start or shut off the car, the warning comes back. Do I
> need to reset something?

First of all, if all you needed was 1 quart after 2600 miles, you are fine.
What is not so good is the oil _pressure_ light coming on in the instrument
cluster (as opposed to oil _level_ warning light on the overhead display). 
Since you did not mention seeing oil level warning light that would come on
first, I would guess that your oil pressure sensor is acting up (a pretty
common occurrence on 10+ year old M20 engines). How is the actual oil level?
If it's fine, replace the oil pressure sensor ($15?).

> When the engine is idleing, there seems to be a light miss, yet the
> minute I step on the gas the engine is as smooth as silk. Does the M20
> engine have a slight miss at idle normally. There is no power loss or
> lack pof performance at any other speed or load. I just changed the
> plugs and it didn't help. It would seem if there was a wire or
> cap/rotor problem, it would show up at higher speeds. Dirty
> Injectors??

Mark,
There are two answers:
1. they all do it;
2. you could have anything from vacuum leaks, 1/2 dozen sensors that could
go flaky on you after 10 years (AFM, temp sensors, crankshaft sensors, etc),
etc. 

Cap/rotor should be replaced every 100K miles. If yours haven't been
replaced recently, have them done. Most likely then not cure your slightly
loopy idle problem.

good luck,
alex f

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