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the heat in my car doesn't work and i have to drive 500 miles

S

Shaftatplanetquake

Diamond Member
500 miles this week. It was 17 degrees here this morning. I was so happy when it warmed up to 35 for my drive home. I drove 90 miles before the sun came up and and 90 more after the sun went down.

Can I go buy a power inverter and use one of my space heaters? Is a cheap (>$100) inverter going to have enough amps to power a space heater? Is the car's electrical system able to handle it?

My real plan is to take the damn car to a shop, but it isn't at all convienent right now.

Thanks guys
 
I'm guessing, but am thinking an inverter needs to be <300w before a fuse blows to the cigarette lighter input.
 
A 1.5kW space heater will demand approximately 153 amperes continuous using an inverter from a 12V electrical system. This assumes a sine wave inverter of decent efficiency AND designed for 1500W+ continuous load!

Not very practical and there's a good chance at highway speed the heat loss will exceed ~5100 btu/hr the heater will output!
 
If your heat doesn't work, you might have a problem with the car's cooling system. Is it that the blower doesn't turn on, or it never gets hot?

If it doesn't get hot, at least make sure (when the car is cold!) that there is enough antifreeze in it. If that's the case, its an issue of the mechanism that diverts coolant into the heater core for your heat that isn't working. Could be the control unit or the switching valve, but it narrows the issue.

And you definitely can't run a space heater from an inverter. Even if the inverter is 100&#37; efficient (it isnt), a 750W space heater would draw ~60 amps @ 12 VDC. You don't have a circuit coming into the car that can handle that. We're talking at least 4 gauge wire to handle that on a 12V system.
 
I thought the car interior heater works off heat from the engine when it gets warm enough....? that is why turning on the heater to HIGH("A/C off" mode) when your car is overheating, helps cool down the engine a little?

if i'm wrong, then FOOT -> MOUTH
 
Rubycon said:
A 1.5kW space heater will demand approximately 153 amperes continuous using an inverter from a 12V electrical system. This assumes a sine wave inverter of decent efficiency AND designed for 1500W+ continuous load!

Not very practical and there's a good chance at highway speed the heat loss will exceed ~5100 btu/hr the heater will output!
Click to expand...

Dude, I really doube that my space heater wouldn't make me warm in my car. It might not be able to be powered on, but if I got past that, I really doubt it wil have a problem heating the thing up well enough for me to have to turn the damn thing off.
 
Shaftatplanetquake said:
Dude, I really doube that my space heater wouldn't make me warm in my car. It might not be able to be powered on, but if I got past that, I really doubt it wil have a problem heating the thing up well enough for me to have to turn the damn thing off.
Click to expand...

Uh, good luck turning it ON. You'll immediately blow a fuse, or if for some reason that fails, burn up your wiring and possibly start a fire.
 
Savarak said:
I thought the car interior heater works off heat from the engine when it gets warm enough....? that is why turning on the heater to HIGH("A/C off" mode) when your car is overheating, helps cool down the engine a little?

if i'm wrong, then FOOT -> MOUTH
Click to expand...

The water circulates through the engine cooling channels and through supply return lines feeding the heater core. This happens regardless if the thermostat (big hose running to radiator) is open or not. The slider from cold to hot is cabled to a damper controlling how much air recirculated inside the cabin passes through the heater core. The heater core is usually always warm.

Soooo if the thermostat is stuck in the summer months and the temperature goes way up you can get some beneficial cooling by turning the fan on HIGH and moving the slider all the way over to HOT. Of course it will get hot as hell inside the car but it's probably better than the radiator cap relieving itself and walking! 😉

Fmr12B said:
Wondering if a heating pad + inverter would work........
Click to expand...

Yes as an ass or back heater. Get some footies and it would probably be fairly comfortable. 😉
 
MikeyIs4Dcats said:
inverter and an electric blanket


j/k
Click to expand...

Actually that would work! Heating pads/electric blankets sip power compared to space heaters. They are heating YOU instead of wasting power to heat the air around you. This is why electric mittens can run off a pair of batteries all day long and keep your hands toasty. 😉
 
sjwaste said:
If your heat doesn't work, you might have a problem with the car's cooling system. Is it that the blower doesn't turn on, or it never gets hot?

If it doesn't get hot, at least make sure (when the car is cold!) that there is enough antifreeze in it. If that's the case, its an issue of the mechanism that diverts coolant into the heater core for your heat that isn't working. Could be the control unit or the switching valve, but it narrows the issue.

And you definitely can't run a space heater from an inverter. Even if the inverter is 100% efficient (it isnt), a 750W space heater would draw ~60 amps @ 12 VDC. You don't have a circuit coming into the car that can handle that. We're talking at least 4 gauge wire to handle that on a 12V system.
Click to expand...

Yeah, the coolant level seems fine. I did a flush a few months ago when I had a recuring "low engine coolant" indicator. I followed the prestone label exactly, except my radiator didn't have a draincock so I drained it by unclamping the lowest radiator hose. I filled back up with a 70/30 mix.

I am not an expert mechanic, this is about as technical as I get.

BTW the low engine coolant indicator still kept coming on and off occasionally until about a month ago it went away and I don't think I've seen it since.

Heres a better description of the issue:

The heat will generally blow cold air. But occasionally hot air will come out. I usually leave the fan in the off position and when I feel warm air radiating from the vents I turn the fan over to the 1 or 2 position. The air usually quickly turns to cold. Then I turn the fan back off.

Also, the heat seems to be more consistent, hotter, and last a lot longer before going back to cold if I am at sustained highway speeds. 80MPH is a lot better than 70MPH. Also, the heat works much better in 40 degree weather than 20 degree weather.
 
Shaftatplanetquake said:
Yeah, the coolant level seems fine. I did a flush a few months ago when I had a recuring "low engine coolant" indicator. I followed the prestone label exactly, except my radiator didn't have a draincock so I drained it by unclamping the lowest radiator hose. I filled back up with a 70/30 mix.

I am not an expert mechanic, this is about as technical as I get.

BTW the low engine coolant indicator still kept coming on and off occasionally until about a month ago it went away and I don't think I've seen it since.

Heres a better description of the issue:

The heat will generally blow cold air. But occasionally hot air will come out. I usually leave the fan in the off position and when I feel warm air radiating from the vents I turn the fan over to the 1 or 2 position. The air usually quickly turns to cold. Then I turn the fan back off.

Also, the heat seems to be more consistent, hotter, and last a lot longer before going back to cold if I am at sustained highway speeds. 80MPH is a lot better than 70MPH. Also, the heat works much better in 40 degree weather than 20 degree weather.
Click to expand...

Is your water pump ok?
 
I plumbed a hot-water type automotive heater into the back of my pick-up 20-some years ago. Had the radiator-style heater core and a built-in fan. Ran on 12 volts, but I don't remember the amperage. (maybe 20-25 amps?)
Seems like it was about $125-$150 at the local NAPA store, but this was in western Wyoming where every dammed thing cost about twice what it would have in civilization.

Kind of like these:

http://www.jcwhitney.com/AUXILIARY_SPACE_HEATERS?ID=12;0;0;0;100001;ProductName;0;0;0;0;2002893;0;0

http://www.jcwhitney.com/HEATER_KIT...;0;0;0;100001;ProductName;0;0;0;0;2002895;0;0


What kind of vehicle is it? (you posted your vehicle's symptoms while I was posting the above)
You COULD have an air bubble in the system that's not allowing hot water into the heater core. Older BMW's were famous for this, so BMW finally added a bleeder screw at the thermostat so you could "burp" the cooling system and get rid of the air. (not only does it not allow the heater to work right, it also causes hot spots in the engine where coolant doesn't circulate properly)
 
Last edited:
Sounds like you may have a coolant level problem. Check that. Otherwise the heater core may be clogged. I always thought coolant was a 50/50 mix.

Do you hear any gurging sounds? You may have air in the coolant system.
 
bctbct said:
Sounds like you may have a coolant level problem. Check that. Otherwise the heater core may be clogged. I always thought coolant was a 50/50 mix.

Do you hear any gurging sounds? You may have air in the coolant system.
Click to expand...

50/50 is good, 70/30 is better.

No, I never hear any gurgling sounds.
 
You know, every time I try to add fluid via the radiator cap, it just dumps the fluid out of some unknown drain underneath the car.

I know its got plenty of fluid in there, but if its got air in it or if its low, I don't really know how to do anything about that.
 
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