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Thread: BMW E63 630i bad start and oil leak fix project

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  1. #1
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    Join Date
    Jul 2013

    BMW E63 630i bad start and oil leak fix project

    Other day we got BMW E63 630i with intermittent bad cold start problem.
    Few garages tried to fix the problem (including main dealer) but had no luck. Its one of the lot examples when diagnostics could bring u to wrong way if u cant think your own head . Car came in with lot faults in engine ECU memory ,including few faults with valvetronic motor,even it was replaced with new one , ECU internal faults , and lot others ,most of them came later on just becouse some systems are not working properly and might be in limp mode .and only of one faulty part could show lot faults .
    Car could work without any problems for weeks ,o can not start every few mornings ,but later all day no problems at all .
    One of very common problems on valvetronic motors are eccentric shaft position sensor fault .It could be oil leak threw sensor or sensor gasket or electrically faulty sensor . Sensor and connection on wiring was full of oil ,so we cleaned sensor and connections but next morning it didnt helped ,and with disconnected sensor it started straight away .So it was first and best sign that sensor is faulty ,as it gives wrong information for variable valve timing motor and it didnt open valves ,so there is no air and fuel mixture in combustion chamber (in cylinders).If we disconnect sensor completely , ECU goes in limp mode and engine works without variable valve timing ,as normal very early engine .
    To replace eccentric shaft sensor need to remove rocker cover ,as its fitted under cover and bolted on to valvetronic system housing .So more troubles came on to our way fixing bad start problem . Rocker cover gasket was very badly leaking ,cos of other very common problem , broken aluminum bolts ,these holds rocker cover on cylinder head .They broke just becouse they got tired of holding cover in its place as they are tightened on quit lot for aluminum bolts and got lot heat .
    Other bad leak threw oil filter housing gasket , oil cooler housing gasket , vanos solenoid O rings ,broken breather hose at the back of the engine ,oil filler cap , eccentric shaft sensor gasket ,so all these was replaced with new ones including rocker cover gasket set and new bolts , and lot lot cleaning and wash all around the engine ,everything was in so terrible condition as the oil leak wasnt fixed for so long time .Later on making more troubles , damaged - broken fan belts, damaged water hoses and other rubber parts including suspension bushes ! Some pictures of how it looked before and after our work !
    Thanks for your time and enjoy the shots !
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