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  1. Join Date
    Oct 2009
    Posts
    10
    #61
    Quote Originally Posted by jick.cejoco View Post
    correction:
    the engine runs on open loop when you first start it and remains in open loop until the coolant temperature signal reaches about 170 degrees fahrenheit. if the CTS is bad (high resistance), the controls remain in open loop regardless you have been driving all day. it also remains in open loop if the engine is overcooled. when you press the throttle above 40% it goes to open loop from closed loop. the closed loop happens when the parameters such as warm engine, throttle not above 40% and there are no problems that would affect the controls to go on limp mode
    Wow, this is too deep for me. If this is just a medical jargon, i would easily get it but no, i dont understand it at all. hehehe peace! sensya na talga mga boss. so basically, if i am still consuming too much fuel after putting back the thermostat, there must be something wrong with the CTS, tama po ba? how would i know if the CTS has gone bad?

  2. Join Date
    Feb 2005
    Posts
    927
    #62
    I've just refitted my thermostat and I feel much more comfortable about it. The car heats up faster, hopefully that will partially solve my high fuel consumption. I only do short trips and my engine temp only reaches normal operating or mid level when I'm already close to my destination. Still gonna observe.

    If you have a busted Coolant Temperature Sensor, my experience with this is that the engine will have hard re-starting especially on the same day after a bit of traveling. The reason for this is the sensor is giving a low temp reading so there's overfueling happening sa mixture when starting.

    You can usually check the reading of the CTS using a OBDII scanner.

  3. Join Date
    Apr 2009
    Posts
    1,902
    #63
    I see, thanks for the correction sir jick!



    I'm currently using a low temperature thermostat that opens at 160 degrees Fahrenheit.

    Does that mean that under normal driving conditions (no throttling above 40%, only low-rpm range til 3000 rpm), my ECU will run open loop and consequently maintain the fuel-rich mix throughout?


  4. Join Date
    Feb 2009
    Posts
    5,010
    #64
    Quote Originally Posted by isa1023 View Post
    I see, thanks for the correction sir jick!



    I'm currently using a low temperature thermostat that opens at 160 degrees Fahrenheit.

    Does that mean that under normal driving conditions (no throttling above 40%, only low-rpm range til 3000 rpm), my ECU will run open loop and consequently maintain the fuel-rich mix throughout?



    the opening temperature of the thermostat does not mean it stops a rise in temperature. the fan thermoswitch does not kick on until around 212 degrees fahrenheit and is controlled to about 235 degrees inside the pressurized cooling system. sure the thermostat may be open, but the heat output of the combustion does not stop there, that's why you control the coolant temperature by means of the radiator fan cycling.

  5. #65
    Quote Originally Posted by isa1023 View Post
    Upon removing the thermostat, we assume that the engine will never reach ideal operating temperature in ideal time on normal driving conditions.

    On EFI systems, the ECU will run rich mixture on "closed loop" after cold starts.

    Does that mean it will always run "closed loop", ie not all sensor signals considered, when you remove the thermostat?

    it will eventually reach the ideal operating temperature on normal driving conditions but on a way longer interval since the engine will heat the coolant anyway until the thermoswitch kicks in to drive the cooling fans, which regulate the optimal temp (turns on and off depending on temp reading).

    the ECU will eventually compensate with the fuel delivery once the temp sending unit sends the correct reading but take note that on highway driving, some vehicles with big radiators will cool the engine down even without the fans operating unless there's a thermostat present.

  6. Join Date
    Mar 2008
    Posts
    575
    #66
    Dear Sirs:

    Several of the things that the thermostat does (aside) from speeding up the warm-up - is:

    1) making the engine's warm-up even - removing the thermostat and its slight restriction to flow means that the water circulation speed in the block and head are faster - which tends to result in UNEVEN cooling within them - especially during cold warm-ups.

    Cooling water will flow faster through the larger passages and slower through the smaller ones - making some areas over-cooled and some hotter - ultimately resulting in thermal distortion of those parts.

    2) By separating both block and radiator water - it keeps the water in the block hotter - and conversely water in the radiator cooler - thus makes the cooling MORE EFFICIENT - as the hotter block water flows into the radiator, its higher temperature difference will allow it to lose heat faster to the ambient air while similarly the cooler radiator water entering will more rapidly cool the block.

    Note that all thermostats do in fact include some sort of relief or hole - not just to allow small flows but mainly to allow the system to fill up in the 1st place - it serves to vent and release the air or steam trapped in the block.

    Best Regards,

    Dusky Lim

  7. Join Date
    Mar 2010
    Posts
    157
    #67
    I recently installed a thermostat rated at 170 deg. to our Nissan Vanette 2.0 Gas Engine (Local Version).
    But before we got our Vanette (second hand) wala na siyang thermostat and it takes a very long time for it to reach normal operating temp.
    My query, is the 170 deg. thermostat too cold because it can only manage to raise the engine temperature to 1/4.

  8. Join Date
    Dec 2005
    Posts
    38,973
    #68
    Quote Originally Posted by iceman_uel View Post
    I recently installed a thermostat rated at 170 deg. to our Nissan Vanette 2.0 Gas Engine (Local Version).
    But before we got our Vanette (second hand) wala na siyang thermostat and it takes a very long time for it to reach normal operating temp.
    My query, is the 170 deg. thermostat too cold because it can only manage to raise the engine temperature to 1/4.
    Bro., is that the original Vanette thermostat? I still own a Vanette, and I still keep its original thermostat, which I replaced some years ago.

    I will check its trigger temperature, as you should only use one (third party) with the same trigger temperature.

    17.0K:out:

  9. Join Date
    Mar 2010
    Posts
    157
    #69
    *CVT
    I have asked Youngbros, Yen Commercial, Nissan Parts and Nis-Parts Banawe where I bought my thermostat and they all told me that it was the OEM for our Vanette. But it only reaches 1/4 temp even in a very hot day and in traffic with a/c on full.

    I'll be glad to know if you can tell me its trigger temp.

  10. Join Date
    Dec 2005
    Posts
    38,973
    #70
    Quote Originally Posted by iceman_uel View Post
    *CVT
    I have asked Youngbros, Yen Commercial, Nissan Parts and Nis-Parts Banawe where I bought my thermostat and they all told me that it was the OEM for our Vanette. But it only reaches 1/4 temp even in a very hot day and in traffic with a/c on full.

    I'll be glad to know if you can tell me its trigger temp.
    I will bro.,- just stay tuned to this thread. Most probably tonight. Or, I will PM you. I have already placed this action item in my personal calendar.

    If you're at 1/4 temp and gas consumption is not really a big deal to you,- then honestly, you should be a happy camper.

    A good number of Vanette owners complain about overheating.

    Just being curious here,- was the radiator changed? Original was 2 rows and you can change that to 3 rows without so much alteration in the engine bay... *** Am still using the original radiator ***

    Is it still fan clutch you're using? *** Am still fan clutch but have replaced the original ***

    Have you relocated your second condenser or heat exchanger (the one that is in front of the radiator)? *** I did and placed it underneath the front passenger *** <<< resolved the issue of abnormal heating years ago. ***

    How about the condenser, which is parallel to the ground (and is originally beneath the radiator)? Was this also relocated somewhere? *** I have not moved this condenser ***

    TIA.

    17.0K:out:
    Last edited by CVT; October 5th, 2012 at 01:58 PM.

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Should you remover thermostat?