Kaltstartprobleme = Kopfdichtung defekt? Interessant

[Erich]

Es muss ja nicht immer gleich das schlimmste sein. Aber ich habe da gerade einen Bericht in roadfly von einem Amerikaner in Stuttgart gefunden, der einen Tip von einem lokalen BMW Monteur bekommen hat.
Kurz gesagt: ueber Nacht kann durch den Druck im Kuehl-System Kuehlwasser durch die Kopfdichtung in den Zylinder eindringen. Deshalb Kaltstartprobleme nach laengerer Standzeit.
Wenn man nun Abends die Kappe vom Behaelter abnimmt, ist der Druck weg. Springt der Motor am naechsten Morgen gut an, ist das ein Zeichen fuer einen eventuell sich ankuendigenden Zylinderkopfschaden.
Interessanter Beitrag und schnell zu testen:

In reading the board about cold start problems for the M30 engine, I have read recommendations for checking bad temp sensors, leaky injectors and bad fuel line check valves. Well, if all of these possible problems check out O.K. and you are still having a cold start problem, then I have another recommended inspection that was passed to me by a local BMW mechanic (I live in Stuttgart Germany). This one is to check for the possibility of a failing head gasket. Here is how you do it:

After the engine has been running at normal operating temp, shut the engine down and then immediately open the coolant cap to let the pressure vent. Leave the cap open and let the car stand overnight. The next morning, tighten the coolant cap and start the car. If the car now starts w/ ease (i.e., normally) then it is very likely that your cold start problem is a result of the head gasket beginning to fail.

How does this test work? Well, with pressure in the coolant system, as an engine w/ a failing head gasket begins to cool a small amount of coolant will bleed into the cylinders. Then with a bit of coolant in the cylinders, the car will be difficult to start after it has been sitting for several hours. But if you release the pressure within the coolant system after you shut off the engine, coolant will not bleed into the cylinders.

I have been struggling with a cold start problems the last several weeks and all the standard tests had checked out OK. Last night and this morning I conducted the head gasket check and unfortunately for me, my engine failed (w/ the coolant cap off all night, this morning my engine started perfectly). It looks like a head gasket replacement is in my very near future.

Anyhow, I thought I would pass this test idea along. Thoughts anyone?

Buck

[JB740]

ist wirklich ein interessanter tip.
für mich hoffentlich nicht so bald (die neuen dichtungen waren inkl. )

gruss jürgen