Ok, we've gotten a few 2 degree Celcius days and I've had my Sport for 6 weeks now so can report on something odd. My prior car was a 2004 Mazda3 Sport, so another small car. I realize that heat is drawn from the engine to warm up the passenger cabin so until the engine is warm, no heat! However, once my Mazda3 started blowing warm/hot air, it STAYED that way and the temp did not fluctuate unless I switched the temp control/fan speed.

My usual routine is to park with temp to max, fan to 0. Start up car, drive away (low engine temp light on). When low temp light turns off, set fan to 1. Once I feel hot air blowing out, I'll set to 2. Oh and usually I only use the vent setting or vent/feet (once air is hot) unless windows are fogging up, then set to windshield setting. I also use "flow through" not "recirculate" since the windows fog up fast on that setting.

What I've noticed on my '09 Fit Sport is that the engine will warm up and blow hot air, but if I slow down, the air then blows cooler. If I STOP and idle (say at a set of lights), within 1 minute the air is blowing totally cool. I can feel it go from hot to warm to cold within that span of time. I monitored the temp closely this AM (now at 1 degree Celcius outside) to be sure I wasn't imagining this. No, every time I slow down, I can feel a perceptible lowering of the temperature of the air being blown into the cabin (left it at maximum heat, fan 1 all the way on my 40 km commute/45 mins). I timed it when totally at a stop...within 1 minute max, the air is totally cold.

Now my winters here in Sudbury typically run in the -20s to -30s (Celcius) range so this is a MAJOR problem. Sure, the cabin warms up once the car is moving fast but surely the temperature should STAY warm once the engine is fully warmed up, right? As I stated above, that's how my Mazda3 worked. Ok, a bit larger than the Fit but still not a huge vehicle...

Has anyone noticed this? I want some input before I book an appointment with my dealership. I'm wondering if maybe there's inadequate insulation of the engine compartment to account for the drastic cooling at lower operating speeds???

 

Its hard to tell if something is actually wrong because our cars lack coolant temperature gauges. The engine itself might be operating within normal tolerances, though it might be leading to your hot/cold problem... I haven't noticed it yet, but it isn't as cold here.

The Mazda 3 does have a 2.3 liter I4, hardly a small engine, though it might be a pretty small car. That's 50% more engine displacement than the Fit.

 

I've noticed what seems like some fluctuation, but I haven't had a chance to drive ours in really cold weather (the couple below freezing nights I've been at the cabin with the Jeep).
I will tell you that a first-gen Civic we had many years ago would drop down out of the operating range on some downhills, and a Montero wouldn't heat it's cabin at 4*F. I'm not sure the Japanese have the whole HVAC thing under control.
It could be an airdoor issue, or a sticking thermostat (traditionally, they stick 'open'). The absence of a real temp gauge is a problem.
Moon

 

I can provide 2 options to help with monitoring coolant temperatures, using the OBD2 port...

ScanGaugeII - Trip Computers + Digital Gauges + Scan Tool

Davis | Automotive | CarChip Products

I have the CarChip from a few years ago (mine's the old serial port version) but I'd say the ScanGauge II is the way to go.

 

Hmm...you have a point! Comparatively larger engine = faster heating.
My concern isn't that it takes the engine longer to heat up (which I haven't noticed) it's that the interior temperature blows COLD when I slow down/idle! It will really not be tolerable once our winter hits around here.

I should just book an appointment with my dealership and chance them looking at me like I'm totally nuts. Better to have the "experts" look it over, just in case there is something wrong with my heating system. I just can't believe that this should be normal by any stretch....

 

Yeah, my "temp guage" was my hand held over the vent. Didn't even need to do that since the minute I slowed down I noticed the temperature dropping. When I was totally stopped the air blew COLD (not less hot, not warm, COLD). There's no way that can be normal even if it is a small car. Once the engine is warmed up, there should be warm/hot air blown into the cabin (with temperature dial set to maximum, fan speed at 1).

 

Heh, that's exactly what I noticed with my old 1990 Corolla. I noticed that with the Fit when I turned the ignition off (engine "cools off" rather quickly), but I haven't really noticed it too much yet stopped at a red light...though I'm sure what you're saying is true. So far I've only had the fans set to around...2-3 at most, with the heat setting set to about 1/3-1/2 of the full heat setting (this is with the average morning temperature of 0°C) and it's been adequate. I never really did know why it starts blowing cool air out so quickly....you know what, if you called them to ask about it, they might actually have a good answer for you without having to actually go in to book an appointment =p

 

Ah I'll just go ahead and book an appointment. No harm having them look at it. I timed it at every light and yes, within 1 minute max the air goes from HOT to COLD (not warm, COLD). No way that's normal. I set my temp to max, fan to 0 until the "cold engine light" turns off, then fan to 1. And my setting is usually vent until hot air comes out, then vent/feet. The air does get HOT, it's just that once I slow down it goes to WARM then when stopped/idling it goes to COLD. Can't figure that one out...

 

Definitely shouldn't be that way. Once it goes cold have you tried moving the dial to 'cold' to see if it gets colder? And then back to warm to see if it gets warmer.

 

Yup. Cold air does get colder but when I put it back to hot, doesn't get MUCH warmer. I wouldn't call it warm at all but different degrees of cold.

Another forum member posted similar issues here: https://www.fitfreak.net/forums/gene...tml#post480647

I asked what his dealership did to fix the problem (which they did) so am hoping for a quick reply! Plan on booking an appointment as soon as I get an idea of what the issue may be.....

 

Canada girl: is your air recirculating or are you getting the outside cold air? I almost never open the vent for outside air so I didn't notice any temp change - but then I am in the south and it's still very warm here.

 

I'm using the "air through" setting, not recirculating. I use that on REALLY hard core cold days only since the windows fog up/freeze on the INSIDE fast on that setting. It's not even that the air isn't heating up adequately because it does, quite quickly once I get moving. It's that it goes hot then only warm if I slow down, then COLD if I'm not moving at all. Can't be right....

 

It sounds like it's just a bad thermostat. The fact that you're getting heat at all indicates the heater core is OK. When you have a bad thermostat, you risk it not closing properly for the engine block to retain enought heat to circulate. The end result is an overheated block and a very cold cooling system.

 

Oh good, a plausible explanation! + rep to you Sir! Yes, it's odd that I AM getting hot air coming out but then it fluctuates depending on engine stress (hence HOT = going over 80 km/hr, WARM = going under 70 km/hr, COLD = idling). Seems logical that it's a bad thermostat. I'll just go ahead and book that appointment now....

 

Ok, "peg leg" answered about his issues with the heating system and this is what he said: "it was a linkage that switched the a/c or cold air to hot air they said it was a simple fix". So I have 2 plausible explanations. Anyhow, this tells me that it IS a defect and that Honda should be able to fix this easily.

I hope it's a simple fix but at least I found out my heater is defective NOW and not when winter hits. As I stated, Sudbury gets very bitterly cold so that's all I need is COLD air blowing out of my vents....

 

I was just doing some investigation myself on the web, since I wasn't 100% convinced about the thermostat being the culprit. It looks like this is a common issue if there is air in your coolant system/not enough coolant fluid. This prevents good circulation while you're idling 'cause either air is blocking the way or there's not enough fluid to flow through the heater core (when you're idling). This isn't a problem when you're moving because everything is forced through quite nicely. To remedy this you can bleed out the cooling line while topping it off while the car is idling. (Open the rad cap, idle the car for 5-10 minutes and keep topping up the rad fluid until it doesn't drop anymore).

Of course the thermostat can be an issue too if it's "sticking"....but apparently that would cause a cycle of hot-warm-hot-warm rather than cold, 'cause your engine shouldn't cool off *that* quickly when idling.

Things are starting to make a bit more sense! I can't guarantee that all of the above is 100% true but that's all I've got right now.

 

Thanks! + Rep to you for looking into this. I'm, um, NOT a DIY type of gal so will let the experts at Honda do any fiddling. Especially since my car is only 6 weeks old (this Wednesday), I don't want to do anything to make thing worse (and, believe me, they would get WAY worse if I even open my hood...NOT mechanically inclined by any stretch).

 

You could always get this for your seats Webasto Seat Heaters


The same thing used to happen to my old Audi, on some days when it was really cold in the negative's, I'd even see the engine temp fall real low while driving on the hwy. But then again that car's AC wouldnt work unless you were doing atleast 40mph. Dammm german electrical gremlins..


Hopefully its something small (ie. linkage, thermostat, etc.) cause winter is coming.

 

Yeah, good thing is that I noticed this NOW when it's only 2 degrees out and not -20 out! Then I'd have a very serious issue... looks from the input I've gotten that it is a defect but likely a minor one that is easily fixed. Just waiting on a return call from my dealership's "appointment coordinator" to get my car booked in...

 

Hopefully this will be your only hiccup in your GR8 Pumpkin. Sounds like an uncharacteristic problem for a Honda, even today's Honda.