Re: 635 CSi - wont even turnover when hot (archive)

My 733i occasionally turns very slowly sometimes when hot and sometimes nearly comes to a halt. This is a differnet symptom than the solinoid issue. I suspect my problem is that the starter itself is getting worn and sometimes binds a bit as it tries to turn. I have a good spare on hand that I intend to install if the problem ever gets too severe.

In your case the added voltamps of two batteries may be sufficient to get it cranking.

On the downside, this is also a classic symptom of a worn engine (particularly old American V-8s), where when cold it cranks easily because of relatively poor compression. When hot, it becomes tighter; things like leaking oil past valve guides etc, can substantially increase compression until the starter can't crank the engine.

My 88 635 CSi wont even try to start when hot, it doesnt even turn over. Leave it for 90 mins or so and it starts fine. It will usually start ok within 10 mins of stopping whaen hot so getting petrol is ok but if I want to stop somewhere for lunch I have to make it a long one! Strangely jump starting from another car will start it. Its not the battery or alternator, both tested fine and the battery was renewed in March 01. I suspect the imobiliser (Cobra)but the supplier says its fine. Any ideas or suggestions welcome

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