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31 votes
Accepted

Why would a mechanic crank heater to maximum

If the cooling system is drained, it needs to be refilled and all air needs to be removed. The mechanic turns the heater on to allow coolant through the heater core to be sure all air is being removed....
Jupiter's user avatar
  • 3,330
9 votes
Accepted

What is more economic to run? Pre-heater or the engine itself?

Let's do a little back-of-the-envelope calculation: Assuming that the heating unit has an efficiency close to 1.0 and that automotive diesel has an energy density of ~39 MJ/l which translates to ~...
jensgram's user avatar
  • 719
9 votes

Can running the heater with the A/C on damage your car?

No way. In fact the system is actually designed that way. The Air Conditioning (A/C) system on your car runs automatically when you are in the Defrost mode. Like you say that setup removes water ...
zipzit's user avatar
  • 6,569
7 votes

Keeping windshield ice-free without heater

Does the air conditioner work? If so, you can blow COLD and DRY air onto the windshield from inside by setting the controls to: A/C, WINDSHIELD, OUTSIDE AIR. The cold/dry/outside air from the A/C ...
RoboKaren's user avatar
  • 278
7 votes
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Excessive Coolant Expansion: Part 2

It's possible that the impeller blades on the water pump are either compromised or gone completely. I ran into a somewhat similar situation with a Chrysler. The engine would not overheat driving. ...
vini_i's user avatar
  • 16k
5 votes
Accepted

Should I use the heater while warming up my car?

You are right that the heater in internal combustion engine powered vehicles usually uses the waste heat of the engine for heating – that's why in the summer you can use the heater to get a bit of ...
dlu's user avatar
  • 14.5k
5 votes

Should I use the heater while warming up my car?

Well, this is a question for a Canadian guy. Here's the thing: in extreme cold (-20C and colder), the moisture coming off your breath will condense as ice and fog on the inside of your windows. Air ...
tlhIngan's user avatar
  • 12.2k
5 votes

Heater problems in 2001 F150

Coolant flow through the heater core is restricted, which means the fan is able to cool off the water in the heater core before it is replaced with warm water. There are a few possible causes for ...
Eric Urban's user avatar
  • 1,286
5 votes

Car heater taking too long to come on if at all?

When the engine was changed, was the heater properly bled when the cooling system was refilled? If there is an air-bubble stopping coolant from flowing properly through the heater, that would create ...
Nick C's user avatar
  • 28.8k
5 votes

How do race drivers clear foggy windscreens?

Fogging happens when there's a temperature differential between one side of the glass and the other. Most racecars are open - they remove the windows to save weight too, so the temperature inside the ...
GdD's user avatar
  • 17k
4 votes

Keeping windshield ice-free without heater

The easiest thing you could use right now is a de-fogging agent. Anything which will keep the humidity off of the windshield. What I'm talking about is something like Rain-X. At least this should keep ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
4 votes

Car heater taking too long to come on if at all?

In addition to Nick C's excellent suggestions there is also a possibility that the thermostat is stuck in the "Open" position - this would mean that coolant is always circulating around the radiator (...
motosubatsu's user avatar
  • 10.2k
4 votes

What is more economic to run? Pre-heater or the engine itself?

Just look at the possible efficiency : you leave the main engine on idle just for the heater - it is not the most efficient at that speed : better under load at say 2000rpm. The pre-heater is doing ...
Solar Mike's user avatar
  • 34.6k
3 votes

foreign object in windshield vent -dangerous?

I used to work as a design/ quality/ manufacturing engineer for an automotive company. I once worked on a car that the owner complained had a premature airbag deployment. Myself and a couple of safety ...
zipzit's user avatar
  • 6,569
3 votes
Accepted

Why is there no air flow thru my heater core?

Air flow in the heater box is not in the direction I originally thought. Having found a diagram, I was able to determine the air is passed thru the AC evaporator core all the time. Then, depending ...
CharlieRB's user avatar
  • 9,015
3 votes

Pacifica heater core hose reconnect

OP Resolved the Issue flow direction was not an issue. OP reconnected hoses and stated the issue is now closed.
DucatiKiller's user avatar
  • 32.9k
3 votes

2012 chevy equinox blows hot air even shut off

This feels like a broken blend door. A blend door controls how much air is allowed to flow past the heater core, or past the a/c evaporator. A broken door means that air physically stuck going past ...
Lynn Crumbling's user avatar
3 votes

Should car heater be working when engine is on but I am not driving?

I am guessing that you have an air pocket in the cooling system. When the cooling system/ engine was replaced they did not remove all the air. While the car is at idle the coolant flow is insufficient ...
mikes's user avatar
  • 20k
3 votes
Accepted

Can you "warm up" an electric car in icy weather?

Your question about being plugged into a charger is an important one. Most (all?) EVs today permit "pre-climate" control in which the vehicle remains connected to the EVSE and will run the air ...
fred_dot_u's user avatar
  • 4,650
3 votes

How do race drivers clear foggy windscreens?

Fog on your windshield doesn't occur due to the difference between one side of the glass and the other, it's because of the dew point of the air. If the glass is below the dew point of the air it ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
3 votes

Car overheating and car smells like coolant

What you described is very much an accurate representation of a leak in the cooling system, localized to the heater core. The smell in the cabin is particularly telling. One can hope that no damage ...
fred_dot_u's user avatar
  • 4,650
2 votes

Ford F150 1999 4.6L anti freeze leaks from drain on engine wall

The heatercore is hot regardless of the position of the knob on the dash. The knob just controls if a small door covers it. If the heater core was replaced with a cheap aftermarket unit it may have ...
Eric Urban's user avatar
  • 1,286
2 votes

Should I use the heater while warming up my car?

If I understand things correctly...the thermostat will not open until your car reaches operating temperature. So at first, you're just blowing air over a cold heater core. As long as that thermostat ...
elrobis's user avatar
  • 391
2 votes

Heat car and defrost windshield with deep cycle battery

You could do something like this, but I don't think a 70 amp-hour (Ah) battery will be up to the task – assuming you only want to charge it once a week. As a general rule you don't want to discharge ...
dlu's user avatar
  • 14.5k
2 votes

Hot air only flows to vents, not to defrost?

Vent Doors in your HVAC system are not working properly You have various doors in your system to direct air to appropriate places as you change the settings on your dash. When you want air to come ...
DucatiKiller's user avatar
  • 32.9k
2 votes

Keeping windshield ice-free without heater

Clean your windshield with a special sponge (most bigger gas stations should have those). Apart from removing dust particles from your windshield (which contribute to fog buildup), they are also ...
user149408's user avatar
2 votes
Accepted

Keeping windshield ice-free without heater

The absolute easiest way to keep the windshield clear is to drive with the window open. This will remove the humidity from the car very quickly. FYI, the humidity comes from your breath, so opening ...
Astor Florida's user avatar
2 votes

Keeping windshield ice-free without heater

Another thing that you might have luck with is to run the fan at low speed with the defroster on (assuming you can control the airflow). That will keep air moving over the windscreen and will help ...
dlu's user avatar
  • 14.5k
2 votes

foreign object in windshield vent -dangerous?

Plastic typically doesn't melt until very hot (325F for some of the lowest ones). For it to catch fire would be even higher. The risk of catching fire are very minimal considering automotive heaters ...
CharlieRB's user avatar
  • 9,015

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