bigjee

Great thread.
I signed up just to give my input since Im having the same issues as the OP.

I live in Winnipeg where temperatures this past week have gone below minus 30C (not including windchill). Im not an engineer and have no mechanical qualification but have been around hondas since I was a kid.

About the temp gauge dropping, there are a few things that are pretty apparent given the experience we are having with 2010 civic.

1) Front bumper is allowing more air flow that previous 8th and 7th gen civics. which leads me to believe the extra mesh for fog lights on the bottom front bumper maybe allowing extra air flow into the engine compartment.

2) the radiator for the 2010's and 09's might be larger than the previous 06-08 models.
Maybe they were designed for 2.4 liter or 2.0 liter engines as opposed to 1.8 ones.

3) If the radiator is too large then that will means that the car will probably never overheat in the summer when using an AC but that means on really cold days you'll have a mild to warm air being blown into the cabin.

To remedy this temperature gauge problem I rarely turn heater dial to max. In fact, I leave it mostly on the first 2-3 red marks.

vladd

When you say it takes more than 15 minutes to heat up, is that with the heat completely off? Turning the heat on when the engine hasn't warmed up makes it take a lot longer to heat up to normal temp.

exdirtbiker

THANK YOU to Tocoma5050 for doing all that work, and sharing it!
Glad to here someone else is having the same problem. Mine is a 2010 Civic EX 4 dr with 53k miles.
I am going to change thermostats with whatever NAPA sells me.
I have had trouble with factory Honda 'stats in the past, although it was on a (new) 2007 XR650R dirtbike. They stick open a little. or alot. but they all failed, not just some.
I really like Honda admitting guilt, but I don't remember having this problem for the last 3 winters, so I am convinced "something has changed". The thermostat is the easiest anwser. If it doesn't get cured, I'll just live with it.

doublethink

I was just about to log and post this same thing.

I had a 1990 Corolla that did this and it drove me insane, went through 3 thermostats, the only thing that somewhat helped was to make sure the temp was set to fully cold before starting the engine, which shuts the valve so only the coolant in the engine compartment was being heated, which helped it reach operating temp faster.

Its a shame the thermostats are only mechanical and there's no way to see what state they are in.

lazlong

To test that theory, tape a piece of cardboard over the openings in the front bumper and see if it heats up better/faster.

exdirtbiker

hmmm.,.... good point. I had a Datsun 310 that ran "too hot" on the PA Turnpike in summer. I put the defroster on full heat and the temp gauge dropped like a stone.
SO the heater core was more efficient than the radiator ?

lazlong

Nah, it just made the system as a whole that much more efficient.

vladd

Was the fan working properly on the radiator? At low speeds, if the fan doesn't work, there's not enough airflow over a radiator to properly cool an engine (hence why the fans are there). When you turn the heat on inside the car, the fan under the dash moves a bunch of air over the heater core similar to how a radiator works.

tacoma5050

Good points. If front bumper is allowing more air flow that may explain some temp drops while driving. But this morning I let my civic sit running in the driveway for 20 minutes and the temp gauge never raised at all. Also even if radiator is larger, I don't suspect that is the issue...because if the engine coolant is not at 180F then the thermostat should not be open and coolant should not be flowing through the radiator anyways....correct??

vladd

It gets to single digit negative temperature Farenheit around here. I don't think it's possible for a car to get to operating temperature while just idling in this kind of weather. It's not good for the car anyway. Even driving can take a while.

tacoma5050

I was considering trading in my 2010 Civic for a 2014…. “if” the 2014 does not have this same problem. But Honda will not tell me what the lowest outdoor temperature is that the 2014 Civic can reach 180F coolant temperature and maintain 180F. A Honda sales guy offered to check one out for me on a very cold day, but….Honda has done away with the temperature gauge in the 2014 Civics and so there is no way to verify what temperature the coolant is reaching (short of reading it from the ODB). Hmmm…I wonder why Honda did away with the coolant temperature gauge ;-)

vladd

So people stop over-thinking and complaining about it?

DaveSi677

really no temperature gauge on the 2014? I really find that hard to believe unless it's part of that screen thing that comes up now.

tech8

The 2014 Civic has a low temp indicator and a high temp indicator.

DaveSi677

Thanks for clarifying tech8!

tacoma5050

Correct, so you can only tell if your coolant temperature is too low or too high. You have no way to tell if your temperature is at 80F, 120F, 150F or 170F

vladd

Is that somehow different from before?

tacoma5050

Hi vladd, I think there is a difference. With the temperature gauge in my 2010 Civic I can tell within 5 degrees what my coolant is at, so I could tell if it was at 85, 90, 95, 100, 105. ..etc.. 180, 185,190, 195...etc.

In 2014 Civic you can only tell two things:
1. that the coolant is over 180, but you have no idea if it's 181 or 205.
2. that the coolant is too low, but you have no idea if its 175 or 80

In the 2014 Civic if the TOO HIGH light comes on, you should pullover immediately since you have no idea its its at 181 or 200. But in the 2010 civic if your coolant was too high, say at 182, you could probably drive to a service station if it was only a few miles away.

petermil

I see this conversation has been going on for a long time with no resolution. That's too bad -- because I have the exact same problem and was hoping to find the answer here. My 2009 Civic also has slow-and-low heat during the NY winter. Last year I had the thermostat replaced with an OEM 180 degree model. No change! Last month, I had a new Wagner 195 degree thermostat installed. No change! The digital gauge never reaches the midpoint, and heat/defrost is just warm. I've had a series of Accords and Civics in the past and all had great heat. I guess there is no solution. I'm sure it's affecting my gas mileage, which is also disappointing. Bummer! Thanks, all.

VtakHellaFastYo

Dang

petermil

Yesterday, I tried Doublethink's trick that worked on his Corolla. I turned the TEMP control all the way down before I started driving. Sure enough, the gauge reached 3, 4 and 5 LED segments more quickly than usual. BUT, I FROZE WHILE I WATCHED IT RISE. Then I turned the TEMP higher, and the gauge dropped down to 4, 3, and 2 bars. It took a long time to rise again, and never reached the normal midpoint. Hence the heat was only warm after that exercise. Looks like Honda screwed up on this one.

vladd

Is this not common knowledge? Turning the heat on when the engine is cold makes it take much longer to heat up. I figured everybody knew this by the time they graduated high school.

Wanted to add, it's normal for the temp to drop back down if you don't wait long enough. I'm driving my Integra right now, it's -5 to 20 F in the morning when I get off work. If I turn the heat on as soon as the temp reaches normal, it'll fall back down for a while before reaching normal again (driving on the freeway). And yes, it's cold.

Are you sure there's a not a range? I know there was on older Hondas, not sure about the 06+ Civic. For example, say the temp gauge shows as "normal operating temp" at 180 degrees. The temp can then drop to say 160 before the gauge changes (keep in mind these numbers are made up for illustration purposes). This keeps people from freaking out when the temp drops when they hit the freeway or when it goes up when they hit city streets after the freeway. The factory temp gauge is a rough estimate, not a super precise number.

bigjee

I dont think the thermostat is either fully open or fully closed like a switch.
So lets say it opens at 180F then it takes the whole radiator to pressurize a lot longer than say a radiator that is half its size. So it takes twice as long to heat a bigger radiator in -30c temps than say a radiator that is half the size.

i think the thermostat opens at below 180F or opens a little bit but definitely before the temp hits 180F. That means there is coolant circulating the entire system before the cars temp gauge reach half way. so even if the thermostat opens a little say at 160F then its still has to heat 2X (civic 2010 radiator) liters of coolant as opposed to x liters (small radiator) of coolant which is what taking so long.

if you let your car sit for 20 min. first thing in the morning it will never reach half way on a very cold day.

winmac

08 civic with basically the same complaint and symptoms. this is my first winter with the car, first off I installed a new Honda thermostat with no change. Knowing the only way to improve the situation was to block airflow, I covered the entire lower bumper opening with a black garbage bag.
It's not ideal but I have good heat and the engine is operating in the normal range, and a bonus my gas mileage has improved to what I was getting in summer.

Shake79

I had the same problem and I just left it..it's true, it is just a guideline.