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Old 01-16-2009, 10:14 AM   #1
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Expansion tank replaced but struggling to start

I'm a first time user on this fantastic site.
I have a 2003 318i Auto. I replaced my expansion tank (after following the DIY instructions on this site). I filled in water/coolant mixture and left the cap off. After a few turns on the ignition, with it struggling to start, it started with a very shaky/rough idle and then gradually smoothed out. With the cap still off, I filled in more water. I then put on the cap and tightened it. After a while, it started getting a shaky/rough idle again and eventually switched off. Now it's struggling to start up again.
All the while, there is a beep coming from somewhere in the engine - the same beep that first appeared when the water tank burst.

Is there something I'm missing - water pressure? resetting of something in the electronic system?
Please advise. Thanks.
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Old 01-16-2009, 10:34 AM   #2
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Just a WAG, but look for a loose vacuum line (the hiss should give it away).

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Old 01-18-2009, 08:22 PM   #3
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Yeah, I'd say something else must be loose. Only thing I can think of near that area is the intake as far as vacuum leaks go. Possible the upper hose on the crank case vent valve(See it next to a VANOS oil line on top of the valve cover)
Even an engine with zero coolant shouldn't idle rough(till it overheats at least) :lol:
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Old 01-19-2009, 01:19 AM   #4
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I managed to get it started. I rev it up and then it gradually loses power i.e. foot down on the gas pedal and no revs. Then, it struggles to start up again. I notice that if I have the radiator cap open, it does start up after lots of fluid spilling out. So, it might be something to do with the water pressure or an electronic setting.
It's going into the dealership today. I'm tired of trying to figure it out and don't really have the luxury of time to wait anymore. My wife needs her car back urgently.
I'll post back the dealership report.
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Old 01-19-2009, 01:36 AM   #5
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I don't know the history on your problem, YOU SAY THE TANK BURST. I hope it did not overheat and blow its head gasket!.
Have you checked the oil to see if it is high and/or brown and like thick(water in the oil, pumped around a bit).
Hope not.
Anyway, most likely what has been suggested, loose vacuum line or maybe water got in the intake, wet the plugs or wires.
Good luck
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Old 01-22-2009, 06:08 AM   #6
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Well, the dealer reported that the engine was overheated and needs to be replaced i.e. the block as well.........OUCH. My wife said that she didn't check the temp guage before she got stuck. Anyways, I got the car towed to someone else who will put in a used engine for 1/6th the price quoted for a new engine by the dealership.
Moral of the story - when you got a leaking expansion tank, don't let your wife drive the car or explain to her how to manage it whilst driving (something I forgot to do). Or better still, get it fixed immediately.
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cooling system, engine beep, expansion tank, start problem

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