Car Problem Reports

BMW 330Ci Coolant Loss Due to Leak from Expansion Tank

BMW 330Ci Problem
21 Reports
Me Too

Model Years Affected: 2001, 2002, 2003, 2004, 2005, 2006

Average Mileage: 90,579 mi (52,481 mi - 125,000 mi)


An engine coolant leak may develop from the expansion tank resulting in engine overheating. When a cooling system component fails the entire cooling system should be inspected. It is not uncommon to find additional component have failed or are leaking.

Overheating can cause severe engine damage. If the engine begins to overheat it is recommended to stop at the first available location and have your vehicle towed to a repair shop.

  • Visitor, , 75,000 mi

    2002 330Ci Same deal. Developed small leak in expansion tank. Took me a while to find where it was leaking from. Removed coolant tank and it appears that when the original tank was made there was a very small crack in the plastic that just got worse over time. Had I not found it earlier it would have been a disaster. No lights came on to warn me. Just that familiar sweet smell of antifreeze every time I would get out of the car after driving. Bought a Meile replacement from eBay for pretty cheap. Did it (pretty easy replacement job) at 70K and still working good 5K later. I did not replace the cap as the rubber inside was still very good. I did drain flush and fill with new coolant mix, checking to make sure the coolant level remained towards the top as it comes out the top. Checked it a couple other times over the next month. Added a small amount of fluid each time. Have to get the air bubbles out of the system. Just goes to show: A well cared for car goes a long way.

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  • Visitor,

    96000 miles same stupid problem...

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  • prwm, , 68,000 mi

    rough idle and overheating
    Replace expansion tank, disa valve and thermostat

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  • Profile_thumbnail

    Expansion tank failed, when replaced it failed again leading to complete engine failure

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  • Visitor, , 108,000 mi

    my coolant tank failed

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  • dekan, , 82,000 mi

    expansion tank cracked

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  • Visitor, , 111,000 mi

    coolant leaking on the ground when parked. Keep refilling it. How much will this repair be? I've had the car since April 2014 and already spent $2000 on it!

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  • Visitor, , 88,000 mi

    leaking coolant

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  • Visitor, , 80,000 mi

    tank leaked

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  • Visitor, , 125,000 mi

    constant drip

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