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View Full Version : 530i heat soak - another take



GerryP
03-14-2008, 07:53 PM
This is my first post - it's a cure not a problem - it's a thankyou for all the good information I've had from this site.:)

First the problem. It started as a classic heat-soak. I'd run the car, park it for ten minutes then come back and find it wouldn't start. Sometimes.

Over a period it got worse until finally the car wouldn't run at all. When it got to that point I found a cure - the distributor contacts were covered with thick grey deposits. I scraped them clean and the car ran fine. For about two weeks. Then the heat soak problem came back.

When I checked, the distributor contacts were again covered with thick grey deposits. I cleaned them again and looked for more problems. I found the spark plugs had a 0.050" gap. I changed that to something a bit more realistic. They didn't need cleaning.

The car's now been running for three months with no further problems. In that department anyway. I can only assume that the deposits in the disti were caused by high voltage breakdown of some sort due to the huge plug gap.

Of course this is the bare bones of the story, the amount of misdirections, agonising and swearing that went into this episode was huge.

In fact fixing this and the cooling circuit (another story) has turned my 'big six' from an sick dog into quite an impressive old motor.