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2010 Honda Civic runs cold in winter

My 2010 civic has a digital water temperature gauge. The gauge does not display numbers, rather it has a LCD bar graph. During the spring, summer and fall the gauge displays 9 bars when the engine is fully heated, which is just shy of the halfway mark on the gauge.

In temperatures below 32 degrees Fahrenheit, the gauge only rises to 4 to 7 bars, even when the car has been driven for over 15 minutes. An odd thing is, sometimes it will display a normal temperature of 9 bars, even on very cold days, say 25 degrees, but this is rare. The heater works OK, the air seems warm enough. It seems that if I turn heater off, that the temp will raise one or two bars.

Maybe these small engines just dont have enough mass to warm up in the winter?
Dealer says nothing is wrong with 2010 civic, but this does not seem right to me. Any ideas, thanks.

Heres the kicker, my old 2001 civic did the same thing in its older years, dealer said there was nothing wrong with that one either. I had replaced the thermostat in the 2001 thinking it was stuck open, but no help.


  • lostwrench1lostwrench1 Ct.Posts: 1,165
    edited February 2012
    I think nothing is wrong.
  • I found this Honda Service News Article from Feb 2010, which states

    - Temperature Gauge Reads Low When It's Cold Outside -
    In very cold weather, your customer might notice that the engine temperature gauge appears to reach the normal operating level a little slower than it would in warm temperatures. This slower movement shouldnt be mistaken for a bad thermostat or any other cooling system problem, as this is typical operation of the temperature gauge. This is because the temperature gauge doesnt operate in a linear fashion like a fuel level gauge does. Check out the example below of this logic shown on a 2006-10 Civic:
    Gauge segment 1 doesnt show until engine temperature reaches approximately 132°F or 56°C.
    Gauge segments 2-9 are approximately 138-165°F or 59-74°C.
    Gauge segments 9-11 Normal operating range is 170-222°F or 77-106°C.
    Gauge segments 12-20 are approximately 228-249°F or 109-121°C.
    Gauge segments 21-22 are approximately 255°F or 124°C.

    On cold days my civic sometimes never rises above 6 or 7 segments, even after 15 to 20 minutes of driving. Which, according to the Honda Service Article, means that my civic is not operating within a normal range on cold days?
  • lostwrench1lostwrench1 Ct.Posts: 1,165
    If your thermostat is working properly............

    The "wind chill factor" has no effect on a non living object. However, the more cold air passing through the radiator the less hot the coolant will be. Your getting different temperature readings while driving at the same cold winter outside temperature could be the result of your going into the wind or travelling in the same direction as the wind. I have an aircraft air speed indicator in my truck and when driving at 65 mph into wind gusts, I often get readings of over 100 mph air speed.

    The radiator's function is to cool the coolant by having air pass through it.

    After driving 20 minutes, park in a place outdoors where wind cannot enter into the radiator. Run the engine for about 5 to10 minutes and see if the temperature gauge rises to the level of your liking. (Be mindful of the exhaust fumes).

    I don't think you have a problem. I would be much more concerned if the temperature gauge was reading on the hot side.
  • Honda USA finally admits my 2010 Civic may not reach "normal" operating temperature in cold weather.

    Honda USA has all along been trying to “explain away” my cars symptom by saying that it was due to my misunderstanding of reading a digital temperature gauge vs. an analog temp gauge. They claimed the digital temp gauge is more responsive and thus I would see these temperature variations that I don’t see on my other cars that have analog gauges.

    I knew they were wrong, because I can feel the air from the heater is just not that warm on very cold days.

    So to disprove Honda, I collected data from the OBD on my Civic and my Pilot. The data shows the engine coolant temperature over 30 minute rides at 10 degrees weather and from a cold start.

    Analyzing the data, it showed that the Civic coolant temperature takes a very long time to rise to 180, then dips to almost 140, and never rises above 158 for the remainder of the trip. (Note: on some trips it never got above 158)

    For the same trip, the Honda Pilot coolant temp rose very quickly to 180 and stayed with 5 degrees of 180 for the whole trip. For both vehicles their temp gauge displayed accurately what the OBD was showing for current temperature.

    So the data proves my temp gauge in the Civic is accurate and the vehicle is not maintaining a coolant temp near 180 like the pilot does.

    From these symptoms it would appear the thermostat is bad or sticking, but the Honda dealer already replaced it twice when they confirmed this problem last year.

    I gave this data to Honda USA, and now Honda finally admits that this symptom is not a result of the way that the digital temp gauge works, but in fact is a result of the cars design. Here is exactly what I received from Honda:

    “The vehicle is operating within normal specifications given the conditions and climate. The best way we are able to describe it is that the efficiency of the cooling system in the car is such that when the temperature is extremely cold out, the vehicle may not reach "normal" operating temperature under the circumstances. The cooling system is simply working so efficiently, combined with the low ambient air temperatures, that the vehicle simply does not get that warm. The only way for it to reach a higher operating temperature under the circumstances would be to limit air flow into the engine compartment (for example placing a piece of cardboard in the front bumper opening in front of the radiator) which would help in increasing this operating temperature. Not that we recommend that, but just as an example. At this point, given the vehicle is operating normally and the HVAC system is operating normally, there is no further action that can be taken to change the situation that you are describing.”

    BTW, I tried the “cardboard” suggestion and it did not help.

    I guess I am just stuck with a Civic that does not have good heat on very cold days. Also Honda USA has refused to these questions: Do all 2010 Civics’ have this problem? Do Civics’ newer than 2010 have this same problem or has it been fixed? And if it has been fixed, how?
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