Car heaters 101

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Originally Posted By: mechtech2
Pre heating the engine is nonsense to me.
Many cars use flaps to control the air flow, and the coolant is always circulated through the core anyhway.
Drive 4-5 minutes with the heat shut off? Are you kidding?


True but when you turn the blower motor on you're dissipating the heat faster [which you're trying to make, to warm the cabin with]. Not having the blower motor on allows a faster warm up, since you're not forcing not cold air through the heater core. This is especially in older vehicles like my E-150 and Aerostar. The other thing is having cold air blowing on you while you're waiting for heat vs. nothing blow on you is a bit more comfortable, at least for me.
 
Originally Posted By: mechtech2
Pre heating the engine is nonsense to me.
Many cars use flaps to control the air flow, and the coolant is always circulated through the core anyhway.
Drive 4-5 minutes with the heat shut off? Are you kidding?


There's no heat coming from cold coolant. Let the engine get some heat into the coolant first, then suck it out of the coolant. Trying to get heat from cold coolant isn't going to happen, no matter how hard one curses at the heater.
 
Originally Posted By: mechtech2
Pre heating the engine is nonsense to me.
Many cars use flaps to control the air flow, and the coolant is always circulated through the core anyway.
Drive 4-5 minutes with the heat shut off? Are you kidding?

Not in my E430, LS400 and S2000. All have heater control valve, the valve is fully close at lowest temp setting and open fully at highest temp setting.

It's confirmed with Ultra-Gauge on the E430 and S2000. After the car was driven for about 2-3 miles, the coolant temp was around 175-180 with heater temperature was at minimum, when I turned the heater to max the coolant temperature dropped 8-10F within 3-5 seconds. That means the coolant is only circulate through the heater core when the temperature is higher than minimum.
 
I just leave the heat on max and the fan on low and directed to the floor vents (Unless of course the defroster is needed). Once the coolant temperature gauge starts to move, then I might turn the fan up if the cabin feels too cold. I think this gets the cabin warm as fast as it's going to happen.
 
Originally Posted By: mechanicx
I just leave the heat on max and the fan on low and directed to the floor vents (Unless of course the defroster is needed). Once the coolant temperature gauge starts to move, then I might turn the fan up if the cabin feels too cold. I think this gets the cabin warm as fast as it's going to happen.


Agreed, 100%...

There are tricks mentioned that will decrease the time it takes to warm the engine, but as far as getting the most from the heater, the above is it...
 
My 02 BMW makes great heat, and it does help a lot to turn the blower almost off until the engine can build some heat. Watching the obc temp, the engine maxes out at maybe 78 deg C driving in town with the blower on auto. If I turn it way down, it will shoot up to 95-98C and stay up there.

I try to do that just to burn condensation if nothing else.

What I'm REALLY jealous of are the Webasto aux heaters available on diesels. They burn diesel to heat the coolant and will even run the blower without the engine running. Your car will already be warm when you get in it, with no wear/tear to the engine! I just don't see how life could be better!
 
Originally Posted By: TFB1
Originally Posted By: mechanicx
I just leave the heat on max and the fan on low and directed to the floor vents (Unless of course the defroster is needed). Once the coolant temperature gauge starts to move, then I might turn the fan up if the cabin feels too cold. I think this gets the cabin warm as fast as it's going to happen.


Agreed, 100%...

There are tricks mentioned that will decrease the time it takes to warm the engine, but as far as getting the most from the heater, the above is it...


I couldn't care less if my engine takes extra five minutes to warm up, the machine is made to serve me, therefore I do what mechanicx is doing to maximize my comfort.
My wife on the other hand just cranks the fan up to the max with a dead cold engine. Believe me, I tried explaining that her method actually increases cabin warm up time, but whenever I'm not in the car with her, that's what happens.
 
Originally Posted By: HTSS_TR
Originally Posted By: mechtech2
Pre heating the engine is nonsense to me.
Many cars use flaps to control the air flow, and the coolant is always circulated through the core anyway.
Drive 4-5 minutes with the heat shut off? Are you kidding?

Not in my E430, LS400 and S2000. All have heater control valve, the valve is fully close at lowest temp setting and open fully at highest temp setting.

It's confirmed with Ultra-Gauge on the E430 and S2000. After the car was driven for about 2-3 miles, the coolant temp was around 175-180 with heater temperature was at minimum, when I turned the heater to max the coolant temperature dropped 8-10F within 3-5 seconds. That means the coolant is only circulate through the heater core when the temperature is higher than minimum.



I also have the Ultragauge and can confirm this on my vehicles.
 
Originally Posted By: KrisZ

My wife on the other hand just cranks the fan up to the max with a dead cold engine. Believe me, I tried explaining that her method actually increases cabin warm up time, but whenever I'm not in the car with her, that's what happens.


Mine's been trained to leave it off for the first 2-3 minutes while driving with me. After that, it's fair game. She's got me trained elsewhere, so it's a fair trade.
 
What? Turn what off?

First of all, I pity you poor guys living in the frozen wastelands.
If we ever do use our heater, and that is rarely, we do NOTHING.

Our cars have auto climate control and will not do anything until there is warmth to be had. The Chevrolet will come on extremely low fan at first and then ramp up gradually to a roar if you need it.

My Chrysler waits about a minute or two and when it comes on it is warm.
 
Getting air flow to the interior [and esp the windshield] as soon as possible is what makes sense in winter.
Even a few degrees above ambient temp is better than ambient temp.
You would lose 4-5 minutes of heat production in the interior for no good reason, if you did not turn the heater on.
 
Originally Posted By: SteveSRT8
Our cars have auto climate control and will not do anything until there is warmth to be had. The Chevrolet will come on extremely low fan at first and then ramp up gradually to a roar if you need it.


Auto climate control does the same thing up here.
wink.gif
I've always told people (and climate control does the same thing) that blasting the fan when you just started the car in -40 is just going to blow -40 air at you. Obviously, the engineers who program the climate control agree, since on the vehicles I've owned with auto climate control, it won't blast the fan until the coolant temperature gauge has begun to move (or it's set to defrost, which will call for a bit extra airflow anyhow).
 
My suby will fully warm up in a matter of a couple of miles, so I just grin and bear it untill then, once its warmed up, I crank on the heater full blast.
 
Originally Posted By: subiedriver
My suby will fully warm up in a matter of a couple of miles, so I just grin and bear it untill then, once its warmed up, I crank on the heater full blast.


Many smaller engined cars have the cooling system volume very tightly controlled and excellent thermostats. It's part of their fuel economy strategy to get that engine HOT quickly and it yields a great heater as a side effect.
 
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