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Thread: Upper radiator hose keep coming off

  1. #1
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    Upper radiator hose keep coming off

    The upper radiator hose just came out at the radiator. Put it back and filled it with distilled water. Drove back home (8 miles). Replaced both hoses (OEM) and also the water pump (Saleri) (as PM). Reused the clamps. Old pump was in excellent shape and hose was worn. Anyway put coolant back and drove it today morning at 84F. No AC was On. After 8 miles (almost same distance), the hose came out again. Again filled with distilled water and drove it back home and came to office in the other car. Luckily both the time, as soon as the coolant started coming out, i found it stopped car. So car never got overheated. Both times, i had to put close to 1 gallon distilled water to fill it.

    What can cause this?

    1) Some thing blocked in the radiator
    2) Bad clamp?
    3) Radiator neck is bad?

    Hoses, Thermostat and Water pumps are new.

    Please see http://s1095.photobucket.com/user/sa...tml?sort=3&o=0. Also click next or previous to see more photos of the same area.

  2. #2
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    Compared to mine, it looks like some one cut off part of your radiator neck, and that it may be cracked.

  3. #3
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    Radiator needs replacement

    Also planning to replace the clamps.
    From http://www.realoem.com/bmw/showparts...43&hg=11&fg=35

    07129952119 - 2of them for the clamp? Anything else needs replacement?

    - - - Updated - - -

    Anyone else had this issue before? Saw a company selling new radiators with one year warranty locally for $90. This brocken neck issue is common? Or some overpressure in the system is causing it?

    http://www.realoem.com/bmw/showparts...43&hg=11&fg=35

  4. #4
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    Mine broke off last summer, it broke off so clean It took the hose coming off another time before I realized it was partially broken off.

  5. #5
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    Quote Originally Posted by saneesh8 View Post
    Anyone else had this issue before? Saw a company selling new radiators with one year warranty locally for $90. This brocken neck issue is common? Or some overpressure in the system is causing it?
    A search of the forums - or even Google - will tell you that the plastic components of BMW radiators (and coolant reservoirs) are prone to becoming brittle and cracking/failing. Those necks the hoses attach to are the worst part.
    Last edited by BMWBergy; 08-05-2013 at 04:07 PM.

  6. #6
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    Thanks to all. Hope no overpressure or anything can cause it right? The radiator looks like the original one (13 yrs old with 117K on it).

  7. #7
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    Same thing happened to mine two summers ago...chalked it up to old age, since it was the original radiator.

  8. #8
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    Quote Originally Posted by saneesh8 View Post
    Thanks to all. Hope no overpressure or anything can cause it right? The radiator looks like the original one (13 yrs old with 117K on it).
    It looks to me like the mounting area is 'hosed' (no pun intended). Looks worn, uneven, and irregular.

  9. #9
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    I guess because not not enough grip and not enough length to clamp properly, it is just getting loose and pushing it back.

    Just want to know, what would be the symptoms of overpressure in the system? Like bad expansion tank cap?

    - - - Updated - - -

    Bought new radiator. Just remove the old one and connect this one and bleed system as normal? Turn ignition and max hot + low fan setting, remove the cap and bleeder screw, fill it slowly and let it run out of the bleeder screw area without any bubbles and close both. Thats all right? Or do i have to do the same thing with engine running?

  10. #10
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    Ignition on without the engine running does nothing on the Z3 as it doesn't have an auxillary water pump.

    Turning the temp to max hot does nothing. It can only not be at max cold, and that only if the key is on. All BMWs for the last 30 years have a full flow heater that is only shut off for Max A/C.

    Removing the cap and opening the bleeder is redundant, the bleed passage is open with the cap removed.

    Revving the snot out of a M52tu or M54 does nothing but airlock the pump.


    In other words, there is a TON of BS out there about bleeding the coolaing system. Add in that there where some serious design changes though the Z3 model range that negate some techniques, and you have a mess. The best method I've found that works on all models is quite simple. Cap off. Fill. Squeeze the lower hose until no more air bubbles are released into the tank. Keep filling and squeezing. You will know when the system won't take any more. Now start engine and run at a fast idle. Squeeze the upper hose and top up fluid as needed until you have a stready stream shooting out of the bleed port into the filler neck. Shut off engine, Adjust level in the tank (too high is bad). Install cap.
    Last edited by rf900rkw; 08-05-2013 at 07:00 PM.


    /.randy

  11. #11
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    I think over tightening a hose clamp will cause the composite/plastic material to break.

  12. #12
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    "Cap off. Fill. Squeeze the lower hose until no more air bubbles are released into the tank. Keep filling and squeezing. You will know when the system won't take any more. Now start engine and run at a fast idle. Squeeze the upper hose and top up fluid as needed until you have a stready stream shooting out of the bleed port into the filler neck. Shut off engine, Adjust level in the tank (too high is bad). Install cap."

    If i run it at fast idle with cap off, will it pushes all the water out of the expansion tank?
    Last edited by saneesh8; 08-06-2013 at 04:46 PM.

  13. #13
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    Pushes it out fast? That should not happen as the tank is on the suction side of the waterpump. Is this a 2.5 or a 2.8?


    /.randy

  14. #14
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    No. I was just asking. Since system is under pressure, will it pushes it out. It is 2.5. If it is on suction side, it will never do this. Thanks. I was always scared to open the cap with engine on.

    The clamps , 07129952119 (2 total, one for each hose), where can i get locally? Only dealers will carry them?
    Last edited by saneesh8; 08-06-2013 at 05:51 PM.

  15. #15
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    If you start the engine cold with the cap off, the fluid level will stay put. It will actually lower a tad as you raise the engine speed, as the tank is on the suction side of the water pump. As the engine warms, expansion will cause the level to rise. You should be able to get to operating temp without it spewing over, but normally it's not necessary to run the engine this long. Some people do, wanting to see the thermostat open before closing the system. But you can't set the tank level with the engine hot.

    Teh one advantage you have is you are in the position to check the coolant level after it sits and cools. Maybe several times. I can't tell a customer the a simple coolant service will take days as I heat bleed and cool the system over and over. Fill, check, deliver.


    /.randy

  16. #16
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    Thanks Randy.. I was always getting confused by different methods. I did like this way after the radiator swap. At the end, i can see that only water is moving, no air bubbles in the expansion tank. Then followed the other process also. Just to make sure, i checked the heat also after this and it seems working fine. Didn't drive much (<1 mile). Need to drive in the evening for couple of miles and need to recheck the coolant level.

    BTW the new radiator neck have a copper tube inside to reinforce it. Old one didn't have it.

  17. #17
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    Just an update. So far no issues. 100+ degree outside. It is still holding good. Thanks to all..

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