3-Series (E21, E30)Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.
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My son has a 318i that as it runs down the road seems to burn clean, but when you put the car into park it starts putting out smoke out the tailpipe. It will clear up once the car is in gear as goes about 100 yards down the road.
We have changed the plugs (we put in platimum sp?, was this wrong) wires, cap and rotor. The fuel filter will be changed out this morning. I will also put the timing light on it as well.
So what about this smoke? anybody have this happen to them?
It's probably pulling oil through the valve seals at idle. You have the highest vacuum at idle, which will pull oil past leaking valve seals/worn valve guides.
Running down the road gives less vacuum.
actually the old toyota we used to have was doing the same thing. so me and my dad took the engine apart, changed valve seals and piston rings and it stopped.
i believe i have the same problem as u, my car tends to emit grey smoke, but when driving it is completely fine.
Since it is an old engine, there may be carbon build-up in the engine and may take a while for the engine to break it down? i might be wrong. i'm not an expert. just giving my suggestion.
I only believe this because when i took my car to get smog checked recently, it failed two times before it passed the third time, and only because the guy drove it around a while, to "break up the carbon in the engine" as what the guy said. After he did that, it passed by a reasonable margin.
Thats interesting that the valve seals are suspect. Today I watched my son start the car after it had been sitting for an hour and it smoked for about 5 seconds and then quit as he drove it off. I know on chevys when they have bad seals that the oil will seep down while it is sitting. I bet thats the problem.
Any way that I can verify this before tearing the head down? I could do a compression check to make sure the rings were ok, but if it were rings, the car would smoke all the time.......
"Interestingly, the attachment hole for a piston pin causes a piston to expand unevenly as the engine heats. A piston is consequently built in an oval shape. When heated to proper running temperature a piston expands to a circular shape, matching the cylinder engine. This is one reason why an automobile engine must reach proper operating temperature to run properly."
Toyota told us that the valve seals usually last up to 170k miles... i dont know how long they last for a BMW though, i haven't needed them yet (thank goodness). But we had to have them replaced at 30k and at 190k....
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