Originally Posted by strsout
I have this old 1992 BMW 525i that is in a faire good conditions and was running preety good until about 1300 miles ago.
It start using too much engine oil. Little less then a quarter every 500/600 miles.
I've beem adding oil since them (the next oil change is schedule to be 2000 miles from now still) and then on the last 400 miles the engine is strugling to keep idle as soon as I turn it on in the morning.
After the engine warm up it will run fine the rest of the day.
Talking with the guy who sold me the car, he told me (now is why I came here. I thinking he is BS me) that probably I need to do few oil changes in a row, like every 500 miles, until all possible old oil inside that engine is gone. The car was stored for about 18 months before he sold it to me and the first think we did, at his place, before turn it on, was change oil and spark plugs and gas, plus all filters.
Could that idea to change oil few times be true? Or do I have another issue here.
The car doesn't burn oil on the emissions (I try with a with paper there, and it burns pretty clean), doesn't lick oil neither. The engine is very clean, and the spark plugs I removed this weekend (only the first 4) were absolute clean, after 3000 miles.
Thank you for any input.
The oil changing procedure is total BS.
I think you have something wrong, but the first thing for me would be a compression check, done after the engine has run for a while reasonably well then shut down and the compression check done. If all 6 plugs look good, dry and tan in color, it is hard to know what is wrong. But if one or more is more oily and or black in color, then those cylinders likely have a ring or valve guide issue. Since you do not see an oil leak, then it must be going through the combustion chambers, and should show up on plugs.
Idle problems could be attributed to many things. There is an idle control valve which controls the idle electrically. If that gets dirty or clogged, then idle control suffers. A vacuum leak, such as intake manifold gaskets etc., fuel injection pressure control, fuel filter, fuel pump, injectors, even a leaking seal on the oil dipstick or filler cap. Also, a leaking seal on the fuel filler cap can cause problems.
I think your biggest problem that has to be delved into first is the oil useage. The idle control may well be just a symptom of what is wrong there.
Another thing to check, look at the crankcase ventilation connection on the front left side of the valve cover. It has two hoses, one larger one on top, and a smaller one on the bottom of it. Check the hoses carefully, the small one goes under the manifold and slips over a fitting near the throttle body, behind the manifold. You can see this if you use a good light and look through the holes in the manifold. You may have to remove the plastic cover first, two bolts under the clip in covers.
Do you get grey/white smoke from the exhaust?