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Thread: stretched head bolts 2002 325ci

  1. #1
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    2002 325ci

    stretched head bolts 2002 325ci

    Went to BMW service center for a head gasket replacement. I knew it was needed. They insisted on doing a leak down test. Two days later they told me cylinders 3 4 and 5 all failed and coolant escaped during test, I knew this already. They didn't want to take head off because head bolts were stretched. My question is: How did they know bolts were stretched without pulling one or even taking valve cover off? They also said I should get new engine

  2. #2
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    Almost all head bolts are a one time use torque to yield bolts.

    They don't have a specific torque amount, but it's something like torque to 26 ft lbs, back off 1/4 turn, torque to 75 ft lbs, tighten 10 degrees, back off half turn, etc, etc. Eventually leading to it's ultimate torque. It also stretches the head bolts that makes them actually longer than what they were before the torquing down.

    Hope that makes some sense.
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  3. #3
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    I strongly recommend you listen to them and replace the entire engine with a good used one. Attempting headgasket repairs on these motors is a huge gamble and usually costs more then replacing with a good used engine. When these cars overheat the block also suffers because it is aluminum. It can warp and crack just like the head, and the threads for the headbolts pull out because they have been weakened by the heat.

    That being said, find a good Indy in your area to do the engine replacement. It will cost way less then having the dealer do it.
    Last edited by legoman67; 04-29-2017 at 07:12 PM.
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    Ex's: 1984 325e, 1988 325IX, 1992 525I, 1995 540i/6, 2002 330i, 2005 330xi, 1992 850i, 2003 330i #1, 2003 330i #2, 2002 330ci, 2004 330ci, 2007 328CI, 2007 335i, 2001 M3, 2006 M5 6 speed

  4. #4
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    BMW issued a sib a long time ago that be for you pull the head you try to retorque the head bolts, because the block is aluminum and if the bolts won't torque and just spin, the threads are stripped. I know there are time certs out there to fix blocks.

  5. #5
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    Quote Originally Posted by jclausen View Post
    BMW issued a sib a long time ago that be for you pull the head you try to retorque the head bolts, because the block is aluminum and if the bolts won't torque and just spin, the threads are stripped. I know there are time certs out there to fix blocks.
    They work very well too, have to use them on the caddy Northstar motors every time you do head gaskets on one.

    Kinda suck to do tho lol
    2000 740i - 149K - Dville Monsoon rear deck speaker upgrade, GROM audio Bluetooth
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  6. #6
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    Quote Originally Posted by legoman67 View Post
    I strongly recommend you listen to them and replace the entire engine with a good used one. Attempting headgasket repairs on these motors is a huge gamble and usually costs more then replacing with a good used engine. When these cars overheat the block also suffers because it is aluminum. It can warp and crack just like the head, and the threads for the headbolts pull out because they have been weakened by the heat.

    That being said, find a good Indy in your area to do the engine replacement. It will cost way less then having the dealer do it.

    IDK about that... I think some people are just scared of mechanic work... Changing the head gasket on my E46 330i really wasn't that bad... It took about 3.5 days worth of concentrated work and I am not a professional. In fact, the only reason it took so long is b/c I had to stop every here and there to ask for guidance from a friend who is a mechanic... With that said, it is definitely doable and is waaayyyy cheaper than replacing the motor if you are doing the work yourself... If you are paying an indy to do all of the work, then I understand why some would rather just swap the motor and be done with it. If you pay an indy to swap the motor you are looking at around a $3k job for motor and labor combined (about half of that is labor), whereas if they are doing the head gasket, probably $2-2.5K (with $2k of that being labor.)

    So again, if you can do the work yourself--I'd do the head gasket as it really isnt that bad--its just that mechanics rape the unknowing with exorbitant costs and there's nothing we can do about it...

    If you do decide to swap the motor, I would keep the old motor, strip it, and part it out to recoup some costs unless you don't need the money...
    Last edited by apathy11303; 04-30-2017 at 02:18 PM.

  7. #7
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    Quote Originally Posted by apathy11303 View Post
    IDK about that... I think some people are just scared of mechanic work... Changing the head gasket on my E46 330i really wasn't that bad... It took about 3.5 days worth of concentrated work and I am not a professional. In fact, the only reason it took so long is b/c I had to stop every here and there to ask for guidance from a friend who is a mechanic... With that said, it is definitely doable and is waaayyyy cheaper than replacing the motor if you are doing the work yourself... If you are paying an indy to do all of the work, then I understand why some would rather just swap the motor and be done with it. If you pay an indy to swap the motor you are looking at around a $3k job for motor and labor combined (about half of that is labor), whereas if they are doing the head gasket, probably $2-2.5K (with $2k of that being labor.)

    So again, if you can do the work yourself--I'd do the head gasket as it really isnt that bad--its just that mechanics rape the unknowing with exorbitant costs and there's nothing we can do about it...

    If you do decide to swap the motor, I would keep the old motor, strip it, and part it out to recoup some costs unless you don't need the money...
    Yes if your doing it yourself its completely different because you arent paying labor. Since the OP took the car to the dealer to be fixed we can assume he isnt up to do this task himself.

    Your forgetting about the high percentage of engines that dont "just need a headgasket", along with the time required to see if the engine will even take new headbolts(torque testing bolts). That best case scenario that the car "only needs a headgasket" is EXTREMELY rare. I never put an aluminum head back on any engine without it being pressure tested and decked at a machine shop. Every E46 head off an overheated engine that ive sent to a machine shop has failed pressure testing due to cracks.

    Here are the 3 ways typically plays out.

    Scenario 1:
    1. customer wants headgasket replaced, insists on it rather then replace engine
    2. Shop spends say 2.5 hours pulling valve cover and torque testing block. ($250)
    3. Block strips out. And either requires a very expensive time cert procedure(labor for this task is insane!!), or replacement engine. Replacement engine is by far the cheaper solution at this point. (total cost after engine is replaced: $3250)

    Scenario 2: (times are based on actual book time values)
    1. customer wants headgasket replaced, insists on it rather then replace engine
    2. Shop spends say 2.5 hours pulling valve cover and testing block. ($250)
    3. Lets say block threads held. Shop spends additional 6 hours pulling the head off. ($600)
    4. Shop sends the head to a machine shop to be checked ($200+)
    5. Head fails pressure testing. At this point the customer has to buy a replacement good head ($500)
    6. Gaskets, seals, and bolts are purchased to reassemble the engine ($400)
    7. Shop spends another 9 hours reassembling the engine. ($900)
    8. Lucky for this customer there were no issues in the lower end and all is well (Total cost: $2,850)
    8 (alternate). Upon reassembly the engine has low oil pressure and it is determined that one of the internal channels in the block is cracked and a new engine is required (this is only 1 scenario i heard recently, coolant passages in the block also crack and the head surface can also warp which would be undetectable without sending the block to a machine shop) (For the sake of argument engine replacement is $3000) (Total cost: $5850)

    Scenario 3:
    1. Customer reports engine overheated and bad head gasket
    2. Engine is replaced with a warrantied engine (Total Cost: $3000)

    Im not much of a gambling man, but id always go with 3. These numbers are also going to typically be low because i did not factor in parts that would be common to all 3 cases(IE Fluids, belts, etc) and any cooling system components that may require replacement or flushing. Also remember that shops arent going to sell you parts at rockauto pricing, and typically will not install customer supplied parts(due to liability if the new part is actually bad.. a whole other discussion).
    Last edited by legoman67; 05-01-2017 at 03:03 AM.
    Current:

    - 09 335i MSport, FBO.
    - 98 Euro M3, Estoril Blue
    - 04 M3, Carbon Black, 6 Speed Coupe
    - 06 M5, Black on Black, Full Leather.
    - 73 3.0CS, Tagia Green, 5 speed M30b35 converted

    Ex's: 1984 325e, 1988 325IX, 1992 525I, 1995 540i/6, 2002 330i, 2005 330xi, 1992 850i, 2003 330i #1, 2003 330i #2, 2002 330ci, 2004 330ci, 2007 328CI, 2007 335i, 2001 M3, 2006 M5 6 speed

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