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Thread: M5 overheating at idle and in traffic.

  1. #76
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    Ok, when did this start to happen? Has it always been overheating since owning it 2 years ago? If not, when did it start to overheat? Maybe you could trace back the works you've done that can affect the cooling system? Maybe you can also try using straight water just for testing if it will still overheat? Also does it overheat even if the AC is off? Maybe the condenser is heating up too much. Yes a lean mixture can heat up your engine. Why do you suspect this?

  2. #77
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    Guys, don't use water inside cooling system please Antifreeze not only doesnt freeze but it also contains anti corrosion additives....

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  3. #78
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    Quote Originally Posted by shervin View Post
    the radiator had been replaced with the right one (number of fins and tubes) and same dimention including thickness!
    result was the same.
    fan clutch is OK eventhough i replaced it with a new one. nothing changes!
    valve clearances are in range 0.32mm (it should be 0.28 - 0.33mm) for both intake and exhaust. (less valve clearance can cause overheat).
    waterpump is OK and fan shroud is on.
    What are the dimensions of the rad? Did you get a new one when you replaced it?

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  4. #79
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    Quote Originally Posted by Mixzzz View Post
    Guys, don't use water inside cooling system please Antifreeze not only doesnt freeze but it also contains anti corrosion additives....

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    Huh? Don't use water?

  5. #80
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    Quote Originally Posted by cirrusblau View Post
    Ok, when did this start to happen? Has it always been overheating since owning it 2 years ago? If not, when did it start to overheat? Maybe you could trace back the works you've done that can affect the cooling system? Maybe you can also try using straight water just for testing if it will still overheat? Also does it overheat even if the AC is off? Maybe the condenser is heating up too much. Yes a lean mixture can heat up your engine. Why do you suspect this?
    Yes she has always been overheating since I own her.
    without AC it takes much longer to overheat, but with AC on, it just take a few minute after stops the car.
    I'm suspect of lean mixture because amount of hydrocarbon in exhaust gas test was only 76ppm and her tailpipe is always clean!.
    I'm using Turner motorsport chip in ECU (the only modification I've don on her) but same result with the OEM chip.
    I used only 2 liter of antifreeze in 12 liter of coolant (about 16%). the rest filled with purified (membrane filtered) water.
    Last edited by shervin; 08-23-2017 at 06:51 AM.

  6. #81
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    Quote Originally Posted by cirrusblau View Post
    Huh? Don't use water?
    Water wetter baby

    It's common in some countries to use water straight out I the well, or even worse plain distilled.

  7. #82
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    Quote Originally Posted by XAlt View Post

    It's common in some countries to use water straight out I the well, or even worse plain distilled.
    Yup it's quite common here in my country to use water straight from the tap in their cooling system. Straight water is the best for cooling but not for the longevity of the cooling system. I was just suggesting it for short term testing purpose.

  8. #83
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    Ok so it can't be waterpump because the rad is hot and the air coming out of it is hot as well. So it basically leaves only radiator itself or the fan. To me it sounds more like a faulty fan clutch (new part doesn't mean it couldnt be faulty) or the fan isn't the right one. Because if it doesn't overheat when driving that means that the radiator is working and when there's more airflow, the engine runs fine.

    What fan clutch did you get? Sometimes cheapo ones tend to be bad out of the box. If it's OK, then the fan has been previously replaced with the wrong one with less blades or smaller diameter.

    Or the explanation is simply that you live in sauna xD. Did you get the car from some "cold" place and you live yourself in quite a hot one? It might lack hot climate option.

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  9. #84
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    Quote Originally Posted by Mixzzz View Post
    Ok so it can't be waterpump because the rad is hot and the air coming out of it is hot as well. So it basically leaves only radiator itself or the fan. To me it sounds more like a faulty fan clutch (new part doesn't mean it couldnt be faulty) or the fan isn't the right one. Because if it doesn't overheat when driving that means that the radiator is working and when there's more airflow, the engine runs fine.

    What fan clutch did you get? Sometimes cheapo ones tend to be bad out of the box. If it's OK, then the fan has been previously replaced with the wrong one with less blades or smaller diameter.

    Or the explanation is simply that you live in sauna xD. Did you get the car from some "cold" place and you live yourself in quite a hot one? It might lack hot climate option.

    Sent from my Samshit SM-G900F using Tapatalk
    The car came from japan 63000km on tacho.
    fan and fan clutch are Ok. clutch start engaging when 76 deg seen on digital temp sensor and fully engages on 85 deg in every engine rpm. I've checked it by a portable tachometer while reving the engine up to 5000rpm fan does revs about 5000 rpm too (very laudly and make storms of hot air).
    I can't understand why this engine makes such a heat!
    Last edited by shervin; 08-23-2017 at 12:05 PM.

  10. #85
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    Fan@5000 is a bad clutch.

    Should disengage at lower revs.
    Last edited by XAlt; 08-23-2017 at 12:07 PM.

  11. #86
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    Quote Originally Posted by XAlt View Post
    Fan@5000 is a bad clutch
    Why?

  12. #87
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    Quote Originally Posted by shervin View Post
    Why?
    Should be disengaged and not making noise.

  13. #88
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    Ever had the MAF checked or rebuilt? M5 MAFs can go out of spec which could cause a lean condition. Although performance would suffer and it would run hotter all the time.

    Jut throwing ideas. Hot at idle would indicate to me:

    1. a lack of flow through the radiator (I.E. partial blocked rad, or pump issues)
    2. Inability of cooling system to keep up with heat generated by engine (hg Leak pushing exhaust gas into cooling system)

    I understand your frustration.

  14. #89
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    Quote Originally Posted by XAlt View Post
    Should be disengaged and not making noise.
    not when temp is more than 85. It's job is to engage till coolant temp goes down then disengage
    less than 80 it engage and disengage periodicaly
    less than 70 it won't engage at all
    Last edited by shervin; 08-23-2017 at 02:54 PM.

  15. #90
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    Red face

    Quote Originally Posted by zubbie View Post
    Ever had the MAF checked or rebuilt? M5 MAFs can go out of spec which could cause a lean condition. Although performance would suffer and it would run hotter all the time.

    Jut throwing ideas. Hot at idle would indicate to me:

    1. a lack of flow through the radiator (I.E. partial blocked rad, or pump issues)
    2. Inability of cooling system to keep up with heat generated by engine (hg Leak pushing exhaust gas into cooling system)

    I understand your frustration.
    Thanks a lot for your understanding. make me not feeling disappointed (lol)
    I was trying to install an e60 530i radiator fan (pwm brushless heavy duty type) to pull more air from radiator at idle but I don't know how to run a pwm ecu controlled fan!
    Last edited by shervin; 08-23-2017 at 03:11 PM.

  16. #91
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    Just about every M5 that I know coming from Japan has had a head gasket issue. Mine included. They have horrible traffic and the cars just sit and idle. I suspect that your head gasket is an issue of some sort. good luck but that is where I would put my
    Money.

  17. #92
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    M5 overheating at idle and in traffic.

    Something is wrong internally with the motor.

    HG failure on low mileage cars that sat for years and years is not uncommon.

    Compression / leak test the engine. I'll bet you have two adjacent holes that are lower than the rest.


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  18. #93
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    compression test 1.jpg
    Quote Originally Posted by NikosX View Post
    Something is wrong internally with the motor.

    HG failure on low mileage cars that sat for years and years is not uncommon.

    Compression / leak test the engine. I'll bet you have two adjacent holes that are lower than the rest.


    Sent from my iPhone using Tapatalk
    compression test result
    you've loosed the bet my friend! (loool)
    Last edited by shervin; 08-24-2017 at 05:54 AM.

  19. #94
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    Leakdown test or hell the $5 liquid tester. Blown HGs won't send compression numbers down meaningfully, they will show up in leakdown.
    Last edited by XAlt; 08-24-2017 at 07:42 AM.

  20. #95
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    Quote Originally Posted by XAlt View Post
    Leakdown test or hell the $5 liquid tester. Blown HGs won't send compression numbers down meaningfully, they will show up in leakdown.
    All right. you good friends have convinced me to do lrakdown test.
    I'll do it tomorrow morning and let you know about the results

  21. #96
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    Just did it right now. I don't have leak down tester but I brought up pistons one by one to TDC and ..... by 100psi compressed air from air compressor.
    just cylinder 2 has very little leakage to the crank case (very small fisssss sound from oil dipstick) . the rest are in perfect condition.
    No leakage to each other or to water circulation system.photo_2017-08-24_22-27-57.jpg
    Last edited by shervin; 08-24-2017 at 03:17 PM.

  22. #97
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    Where do you live? I mean is it hot there? What are the temps? And can you give give me last seven characters of your vin?

    There's different water pump and pulley for hot climate versions.... Maybe that could be the cause for overheating

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    Last edited by Mixzzz; 08-24-2017 at 04:16 PM.

  23. #98
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    I'm guessing he lives in Tehran. Did the e34 ever get a hot weather package?
    demet

  24. #99
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    Japan should usually have a hot weather package.

    But yea OP, check the part #s
    Last edited by XAlt; 08-24-2017 at 04:55 PM.

  25. #100
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    Dont rule out water pump - it could have lost a vane or two on the pump as has lost all its efficiency.

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