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Discussion Starter · #1 ·
I don't knw if I am alone with this problem?


When I start, adjusting temperature to 21, everything is perfect. After driving for about 45 minutes, suddenly it start to blow cold air. I have to rise temp to 22.5.


It is doing the same thing on every long travel.

I am having a lot of problem with my hybrid 2018. Had nothing with my 2015 in 3 years.

Rear deck rattling.
Weird noise when I brake backward.
Radio rebooting.
Engine vibrating when cold a certain rpm.
wireless charging not working with iphone 8
some warning beep occur often when there is nothing anywhere.
 

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I don't knw if I am alone with this problem?


When I start, adjusting temperature to 21, everything is perfect. After driving for about 45 minutes, suddenly it start to blow cold air. I have to rise temp to 22.5.


It is doing the same thing on every long travel.

I am having a lot of problem with my hybrid 2018. Had nothing with my 2015 in 3 years.

Rear deck rattling.
Weird noise when I brake backward.
Radio rebooting.
Engine vibrating when cold a certain rpm.
wireless charging not working with iphone 8
some warning beep occur often when there is nothing anywhere.
As reported in another thread, I have the same issue with the climate control. It also occurs when in a/c mode. I believe it has something to do with the solar sensor on the dash top. No other problems, however. Great car with excellent fuel mileage for all that power and response. 32 mpg average over 10,000 miles with my 2.0T 10 speed.
 

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Discussion Starter · #3 ·
But my heating problem occur also at night. about 40 minutes after driving on the highway I have to raise the temp from 20 to 23
 

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Just posted to the Inconsistent Climate Control thread - same problem here, happens 30-45 min into a drive (city or highway)
 

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Here is what I think is happening.

First, the engine needs to get heated to achieve an optimal temperature. During this time, the flow of coolant around the engine is restricted. It does not go directly back to the radiator, but is blocked by the thermostat so that everything can heat up.

During this time, you can get some hot water through your heater. You will reach a fairly hot temperature fairly quickly because only HALF of the cooling system is engaged. They do this to make sure that the engine is able to warm up to the point of efficient combustion; if they did not do that, the amount of time during which the engine would be putting out smelly unburned fuel would be prolonged. Perhaps you have smelled the exhaust of a car that has just started. That smell goes away when the engine heats up because the fuel is being completely burned.

When you turn on your heater, you DELAY the heating up of your engine. Y'all probably too young to remember the cars of the 1960s. Well those cars, when they used to overheat, which happened a lot back then, you would turn on the heater and roll down the windows to help keep the engine cool. I haven't seen anyone do that in 40 years. Cars are better at doing what they do these days, you hardly ever see them overheat.

Anyhow, just be aware, that when you turn the heat on, you are delaying the heating up of your engine.

So now you're driving along and things start to seem OK. The heater is working and you have your car set to say 20C.

But THEN, what happens is the thermostat OPENS. Now *ALL* the coolant, the part of it that was held in reserve and not circulating, is released into circulation. This half of the water is cooler. When it mixes with the water that was circulating through your engine, it cools down the hot water and the hot water warms it up. The result is a lower temperature overall. You feel that the heat has gone down or off. So, you respond by turning the heat up to say 23C. Not only that, but the fan turns on to cool the engine and also increase the rate of air flow through the radiator.

At this point you're probably going to be stuck with keeping the temperature at 23 instead of 20. Why? Because now you have in circulation the full supply of coolant not only through the engine, but through the radiator. The radiator is very good at cooling things down. So when the water is fully circulating through the radiator it is going to be, on average, cooler than the very limited supply of water was at the beginning. Because that supply of water was just circulating around and around in the engine, with the objective of getting the engine hot enough to have efficient combustion (and best mpg, etc.). In other words you are assuming that the heating you get in the first few miles is "normal." But that's not so. It is normal only in the sense that you get that initial highly efficient heating of the passenger cabin because a restricted supply of water is circulating through the engine.

When you drive for a long time, the water circulation is fully opened up and you actually experience the "normal" amount of heat that the system can circulate through your cabin.

There are things that you can do.

1. Put the car into sport mode. This raises the RPM. The pistons go up and down faster and will generate more heat. In my old car I used to drive in 2nd gear to keep the high rpms until the car began to give me some heat, this was something I did in the winter. You will consume more fuel but you will be warmer.

2. Get a car bra for the cooler seasons. It will decrease the efficiency of the radiator and the air flow going over the engine. There may be other radiator shields that are available that go internally. I haven't looked into these. One trick in very cold areas is to put a collapsed cardboard box in front of the radiator. If you do this you have to pay attention to the temperature outside and make sure your engine doesn't overheat during the day. This past winter, on my 2014 Accord, I did have a cardboard box in front of the radiator, but even on relatively warm days, say 40 to 50F or 5-10C, the car did not even come close to overheating.

I think the basic engineering problem is that very small engines such as you find on a hybrid or even the new turbo 1.5 litre, there is not a great deal of waste heat. The more efficient the engine is, the less heat is available in the cabin.

I've never had a hybrid because I think they are a bad idea in the U.S. northeast, though I see many of them around. I also don't like the idea of a car with two different types of engines, it seems to me extremely complex.

In any case if the standard water cooling system is being used it might very well be the case that the system is functioning "normally." I suppose there is a possibility that the thermostat is defective and should be opening up sooner. But I think it more likely that the "solution" is to set your temp to 23 because this is how the system works.

We have an opposite problem in our kitchen coffee maker. The you turn the electric coffee pot on and water gets sucked over a heating element and heated, and released over the coffee beans where it falls into the pot as coffee. The coffee is not hot enough when it is just made. That is because the heating element under the glass coffee pot is also the heating element that boils the water before it drips down. The circulating water cools the burner and the result is that the coffee is not very hot when it is fresh. Once the coffee is made, there is no more water circulating through the burner coil and it gets hotter after about 20 minutes. So we can drink the coffee 20 minutes later, or we can microwave the coffee in our cups to increase its temperature. But the system is operating the way it was designed, and it so happens, that the system makes coffee that is lukewarm and only later makes it hot.

With the car heater you get more waste heat from the engine in the early phase when the car has been deliberately engineered to build up heat and get to efficiency combustion temperatures. But when the operating temperature of the engine is achieved, the radiator system fully opens and circulates, and you're driving at a good highway speed, the cooling efficiency is increased, and there is less heat for the cabin.

To increase the heat out put you need to introduce some inefficiency. On a hybrid you might not have the option of sport mode. The engine might be designed to operate at one and only one speed, while the battery pack does the rest. If that's true then you can't increase engine rpm by running in sport mode.

Greg N
 
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This is a good video

 

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None of this info addresses the issue. Auto climate control should be just that, automatic. Like your home thermostat, just set and forget. I have owned previous cars, including Accords, with automatic climate control that did just that; started and maintained the desired temperature that you requested. No fiddling around with the temperature setting. All Honda service people say the same, “we know of no issue”. What I don’t know is if other Honda models have this issue. Somewhere I read of a Pilot owner complaining about this. The effect is more noticeable on the heat side as the ambient temperature goes down.
 

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I don't really have a problem with my Climate Control, but here's what I think is happening:
If the outside ambient temperature is close to your setting, the system is bouncing back and forth between heat and A/C. In which case, you'll feel it go from warm air to cool after the cabin reaches your desired temperature. I think this is especially true when it's cool outside.
21°C is 69.8°F, which is already on the cool side. I keep mine at 74°F (23.3°C), but only notice change over to cool air when the outside ambient air is close to 74°F. In which case, I turn the system off and just enjoy the ambient temperature.
 

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I don't really have a problem with my Climate Control, but here's what I think is happening:
If the outside ambient temperature is close to your setting, the system is bouncing back and forth between heat and A/C. In which case, you'll feel it go from warm air to cool after the cabin reaches your desired temperature. I think this is especially true when it's cool outside.
21°C is 69.8°F, which is already on the cool side. I keep mine at 74°F (23.3°C), but only notice change over to cool air when the outside ambient air is close to 74°F. In which case, I turn the system off and just enjoy the ambient temperature.
In cold(er) weather I always select a/c OFF. I am aware that the automatic function is designed to work anyway. Also I reported the problem is more noticeable as the ambient goes down. I used 20 deg. F as an example. Gets even worse below that. Please re-read my multiple posts on the subject on multiple threads. Above 45 degrees F. the effect is not noticeable.
 
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