1st Gen R53 Cooper S New temp gauge registers hot.

Discussion in '1st Generation: 2002–06 R50, R53 & 2004–08 R52' started by JOHNHOF, Sep 19, 2011.

  1. JOHNHOF

    JOHNHOF New Member

    Aug 16, 2011
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    The car is a 2008 Cooper S.

    I installed a STRI X-line water temp gauge and a STRI X-line oil pressure gauge.

    To install the water temp sending unit I used a hot link water temp port adapter in place of the stock coupling on the upper hose. I lost about 8 oz of antifreeze while swapping the couplings and I put about 8 oz of new antifreeze in the resevior.

    I ran the car in the garage for about 20 minutes and all seemed OK. On my way to work this morning the temp gauge started indicating 230 degrees and the gauge started flashing to let me know the temp was hot. I turned on the heater and the defrost and I get very hot air out of the vents. The temp rises while while the engine is running and the car is moving and the temp goes down a little when the engine is running and the car is not moving.

    My first thought is that I need to burp the system but I am confused by the heater working and the cooler temp while not moving.
    Another thought is that the new gauge is not accurate.

    Is there a way to test the accuracy of the gauge?

    Were is the bleeder for burping this system and are there any special things about the R56 I need to know when bleeding the coolant. I am familiar with bleeding a coolant system on BMWS.

    Thanks,
    John Hoffner
     
  2. Metalman

    Metalman Well-Known Member
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    The R56 can be difficult to "burp" all of the air out of the cooling system. On the waterpump / thermostat housing there is a bleeder screw #7 on the picture. The shop manual talks about turning the heater on and the fan blower. And to add small amounts of coolant to the overflow tank keeping it above the low fill mark. The dealers have a vacuum system that removes the air if you decide to go that route.

    [​IMG]
     
  3. Redbeard

    Redbeard JCW: because fast is fun!
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    The R56 does run "hot" as an FYI. Mine in a highway cruise stays between 218-220 deg F with drops to 215 and spikes to 224. Now, 230 is definitely too hot. I'd say get a burp done by a shop and then have a look at it.

    They mystery is partially solved by how the ECU decides to spin the water-pump as it is electric. If you had tunred your A/C to full blast you probably would have seen lower coolant temps as that tells the water pump to spin faster. Counter-intuitive from a mechanical water pump. If I have the A/C on full blast on the highway I will see cruising temps of 180 deg F with 5 degrees of plus/minus movement.
     
  4. Gil-galad

    Gil-galad Club Coordinator

    May 19, 2009
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    My highway cruise temps are identical to what Redbeard is seeing.
     
  5. JOHNHOF

    JOHNHOF New Member

    Aug 16, 2011
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    Thank you all for the help. I burped it last night but I think it needs to be burped more. I am surprised these cars run that hot and knowing this is a big help.

    Thanks again for the help I truly do appreciate it and I hope I can repay the favor down the road.

    John Hoffner
     
  6. Redbeard

    Redbeard JCW: because fast is fun!
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    Happy to help. :Thumbsup: I just hope you get your issues solved.

    I will point out that at standard op temps if you do lose a hose, get a crack in the system, lose a seal in the water-pump, etc... you've got a VERY short window to get the car shut down to prevent overheating issues as coolant will be spraying like crazy. :eek6:
     
  7. grodenglaive

    grodenglaive New Member

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    That bleeder screw is hard to find. The first time I unscrewed the brake vacuum line instead. :eek:
    If it's any consolation, I am also running close to 230 after installing a temp gauge, but I will try to burp the system some more. Let us know if you have any success getting the temps down.
     
  8. Redbeard

    Redbeard JCW: because fast is fun!
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    I'm wondering if that is a variance related to location of the tap point for the gauge versus the ECUs temp gauge location.
     
  9. DneprDave

    DneprDave Well-Known Member
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    The ECU temperature sender location is right at the thermostat If anything, it would register faster and higher than the sender at the hot link. At least until everything warmed up.

    Dave
     
  10. agranger

    agranger MINI of the Month June 2009
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    My Haynes guide was very specific about turning the heater on high and opening the windows while bleeding the cooling system (for an R53). I assume that it has to do with opening the valve to run hot coolant into the heater core so that you bleed those lines as well.
     
  11. JOHNHOF

    JOHNHOF New Member

    Aug 16, 2011
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    Coolant temp.

    My car ended up being with the MINI dealer for two weeks while they worked on this problem. The ECU had to be replaced to get the slow speed cooling fan to turn on.
    My only problem now is that the gauge registers hotter than the actual temp. and the dealer says it is because there is no ideal place to install the sending unit. I installed it in line of the top radiator hose.
    In what direction does the coolant flow to the radiator in this system? Does the warm water enter the radiator on the passenger side of the car and exit the radiator cooler on the driver side?
    The issue is this gauge is factory set to flash a warning when the coolant reaches 230 degrees so the gauge flashes a warning to me every so often and for only a brief moment before the coolant cools back down. If I can figure out how to get it to register about 10 degrees lower at the top of its cycle it will be closer to the actual reading and the warning won't go off. Once I have that sorted the system will be great as the warning will come on plenty soon enough for me to shut down the engine if it gets hot.

    Any ideas?

    Thanks,
    John
     
  12. grodenglaive

    grodenglaive New Member

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    It could be that the gauge is out of calibration. If you have access to an OBDII reader, you could compare your gauge to what the ecu reads. I don't know if it's possible to calibrate it yourself - is there a calibration screw on the back? If your gauge is still under warranty then you should return it if it's reading high.
     
  13. HRM

    HRM New Member

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    I think the assumption that the gauge is wrong might be suspect. If you think so, send it back to them and get a new one. More likely the temp is accurate and that is how hot the water is in that location. The factory uses a different location and the temp is different there.
     

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