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Old 5th July 2016, 10:29   #1
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Burning hot tubes under the dashboard?

Yesterday, after a 150 KM drive, I accidentally touched some metal under the dashboard of my 2012 i20 Sportz (petrol) and immediately got a blister on my hand. I was not expecting something soo hot inside the car and below the dashboard that it can burn my skin so did a little check using a torch and found that the aluminum tubes going to the heater core are exposed around an inch and I accidentally touched them. With this, there are some questions which I am trying to find answers for.

1. I ran my car with AC on (Not heater) so why was the heater core hot?

Possible answer : The car has auto climate and possible that it occasionally enabled the heater core to maintain the temperature of the air. Did some research online and there is supposed to be some kind of valve to stop the hot coolant entry to the heater core when not needed. How to test if the valve is working fine?

2. The heater core may be making the car cabin hot?

Possible answer : The heater core has a good insulation but can still heat the cabin which will be cooled by the cool air from A.C but still can and will make the A.C run more than needed and in-turn waste fuel.


3. How to test and ensure that heater core is not used when not needed?

Query : Any fool proof method to test the working of system? Can we manually disable heater core if not needed like in summer?


Please share your views and experiences. I am concerned that the auto climate may do more harm than good in some situation and I wish to find a method which will ensure that hot heater core is not heating my car interiors unnecessarily.
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Old 5th July 2016, 11:55   #2
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re: Burning hot tubes under the dashboard?

The heater core behind the dashboard has coolant circulating through it, and it will be hot as long as the engine is running. When you want heat in the cabin you either rotate the dial towards Red section or raise the temperature in ACC control unit. When you do this a flap repositions accordingly and air gets drawn through the heater core and gets heated. This is how it works.

In some cases there is a valve on the coolant circuit feeding the heater core. And this valve can shut the coolant supply to the heater core. In such cases the heater core does not gets engine coolant and remains at ambient temp as long as the valve in the coolant circuit is closed.

For eg in old Octavia sold in india with and without ACC there is no valve in the coolant circuit that feeds the heater core. But the same car in some other markets come with a valve in the engine bay which can shut off or maybe regulate coolant flow to heater core in cabin.

In i10 also there is no valve, so coolant always passes through heater core.

ACC= Auto Climate Control

Last edited by Sankar : 5th July 2016 at 11:56.
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Old 5th July 2016, 16:24   #3
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re: Burning hot tubes under the dashboard?

Quote:
Originally Posted by sanjeevgpc View Post

Please share your views and experiences. I am concerned that the auto climate may do more harm than good in some situation and I wish to find a method which will ensure that hot heater core is not heating my car interiors unnecessarily.
It is working as expected as Sankar explained unless the cabin cooling is not up to the mark and that can be due to other reasons and not just this.

But I was curious as to why you shoved your hands below the dash?
As far as I know, the coolant pipes are quite out of reach to avoid these incidents unless you actually look for it in the organised mess under the dash.

Last edited by tharian : 5th July 2016 at 16:26.
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Old 5th July 2016, 16:37   #4
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re: Burning hot tubes under the dashboard?

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Originally Posted by tharian View Post
But I was curious as to why you shoved your hands below the dash?
As far as I know, the coolant pipes are quite out of reach to avoid these incidents unless you actually look for it in the organised mess under the dash.
While getting out of the seat, noticed a hanging wire and tried to push it back up behind the dash and that's when I touch the small exposed part of the tube. And no the tubes are not too deep inside, they are just covered with plastic padding so they remain out of reach.

I will go to ASS whenever I get time to check if a valve exists and is working fine and see how to cover the exposed part. Will even find out if I can control closure of valve at wish so the heater core doesn't unnecessarily heat the car cabin.
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Old 5th July 2016, 17:39   #5
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re: Burning hot tubes under the dashboard?

And to add to the discussion, when you visit the ASC, make sure they dont do some jugaad patch up to cover the pipe. Make sure that the material they cover the pipes with will be heat resistant. Else over a period of time this material might emanate a burning smell due to the heat and create another panic I would suggest not to cover it at all, unless you have some material you are sure of not causing trouble.
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Old 7th July 2016, 09:44   #6
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Re: Burning hot tubes under the dashboard?

I drove my car today morning for 30 mins, kept the A.C off and checked the heater core tube only to find it super hot. So either there is no coolant valve or its not working correctly.
I would have liked the coolant valve as it would avoid unnecessary heating of cabin as whatever material Hyundai may be using, it can not be 100% insulator.
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Old 4th November 2017, 00:27   #7
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2017 Nissan Sunny XL (P) - Aluminium Tube In Cabin Runs Very, Very Hot!

This is the curious case of an aluminium tube that's accessible from the front passenger footwell, that I just happened to realise today, quite by accident, that runs extremely hot!

So you peek to your right upper corner in the front passenger footwell, just below the area where the glove compartment ends and where the plastic cladding of the center console starts upwards (see attached image), and there's an aluminium tube at a somewhat 45° angle.

Does anybody know what this is for? The vehicle is due for the first service in about two weeks time, so I will enquire with the service center, but I just wanted to see if the good folks on this forum had any ideas.

I, for one, am concerned if the extreme heat will affect any plastic parts in the immediate vicinity.
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Old 4th November 2017, 07:37   #8
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Re: 2017 Nissan Sunny XL (P) - Aluminium Tube In Cabin Runs Very, Very Hot!

Quote:
Originally Posted by arnieshwartz View Post
This is the curious case of an aluminium tube that's accessible from the front passenger footwell, that I just happened to realise today, quite by accident, that runs extremely hot!
Please refer to the post #2 above, by @Sankar. Nothing to worry about. The pipe is exposed in quite a few cars, and it's normal. Heat related aspects are taken care of in design itself.
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Old 4th November 2017, 09:03   #9
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Re: 2017 Nissan Sunny XL (P) - Aluminium Tube In Cabin Runs Very, Very Hot!

Quote:
Originally Posted by condor View Post
Please refer to the post #2 above, by @Sankar. Nothing to worry about. The pipe is exposed in quite a few cars, and it's normal. Heat related aspects are taken care of in design itself.
Whew. I had a feeling it could be something related to the heating system, but wasnt sure since I hadnt even turned on the air conditioning or heater. It's good to know this isnt anything of concern, thanks!
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