No start, clicks
 

Been a while since I've been here since the X5 3.0 has been running perfectly. I know, unicorn stuff, right?


But.


When we had a nasty cold snap it wouldn't start. When I turn the key it just would click repeatedly as long as the key was held in the crank position, accompanied by the dash lights blinking off and on. Sometimes letting it click away for a few seconds would then actually crank the engine at normal speed and away it would go. Sometimes boosting it would let it start, but today it just hit and cranked.



I'm reluctant to replace the starter on spec since it's a pain being under the intake. Anybody can confirm that a continuous 'click' when trying to start it is a bad starter? In my experience, a low battery would give a click followed by a slow or no crank. But this doesn't sound like the solenoid is pulling all the way in. :dunno:

Low battery symptom exactly as you describe. Jump start and drive a good while to charge.

That had been my thought, but the "sometimes letting it click away for a few seconds would then actually crank the engine at normal speed and away it would go" doesn't make sense.

You could put it on a charger with a maintenance mode to get the battery to full, and then try again. At least to rule the battery out. If the battery is close to 5 years, then replace anyway. Get it load tested to rule it out.

Still normal. Batteries can be dropping a lot of voltage internally when cold and pulling current warms them up.

Still you need to as mentioned load test the battery and figure it out.

Also you can measure the current on the starter to determine if it's at fault. Quite often people will replace a good battery because a bad starter is pulling 2x or even 3x the normal current.

Just to repeat what others have said, I had the exact same symptoms with my E39 and the reason was the battery. Jumpstarting didn't work so started the car with a spare battery and later bought a replacement.

I'll be doing a load test tonight. Battery was new last July.

No start, clicks
 

Check the b+ connector under the hood. It can get loose and kill the power to the starter. Also did you measure the battery voltage or monitor the voltage while driving to make sure the alternator is going its job?

New ≠ fixed so follow up as you mentioned on load test the battery. Unfortunately kind of difficult to reproduce if the ambient temperature isn't deep freeze while you had the problem but the load tester does try to approximate the temp current capability