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I have a 2004 Ford Focus I bought cheap around September. I used the A/C like once or twice but mainly used the windows as I preferred it driving through town.

One day I tried to use the A/CC again and it never turned on. Few months go by, it's winter and I'm sick and tired of no heat let alone defrosters. so I, having little to no knowledge of vehicles go to sleuthing about, and find the motor blower plug to be burned out.

I wiggle it around and get it to work, then I find my knob only works when turning to the left for selecting vents. Turns out it pulls a set of wires to change vents, and one is broken. I reach up under and turn the vents myself to defrost, thinking I just solved all my problems, I found I had little to no heat at all coming through.

I had no idea what to do for that, so I reluctantly went with sitting outside of work for 20 minutes while I waited for my windows to defrost using luke warm air, hoping I could make it home before it fully fogged up again (I usually did not make it home before fully fogged).

One day, particularly cold, I went outside and started the car ahead of time(expecting to be out of work 20mins from then) I did not get out till 40mins later. the cars thermometer was at the halfway mark(which is the normal operating temp for it since I've had it) and the windows I could see decently though.

On my way home (1.6-1.7 miles) the temperature started to rise, and by the time I got home, the overheat light came on, and the gauge had just hit red. I parked and checked the oil which was fine. so I went inside and talked to my grandpa, and told him about it and he suggested checking the coolant, to which I found was completely empty(there's no radiator cap, only the overflow) so I took my grandpas van and got a bottle from Walmart, and it took the whole bottle.

I assumed a hose was leaking, and I could hear it and steam spouting out when it got hot. I took it into bestone tire and had them check the hoses. They said they couldn't pinpoint it but it was def coming from either the head, or the block.

So I tried block sealant and it didn't work. Now I'm in need of a new car, but until then, I still need to use this one. Currently, I put antifreeze in when I can, but there's no telling how long it will last. I've had it sit all weekend and the levels change, and I've had the damn thing be empty the morning after filling it.

Currently I use it as my work vehicle, driving 1.6-1.7 miles to work and back, in town the whole time, but I don't know if I'll eventually find myself stranded or what.

TLDR;

I drove the car without coolant, overheat light came on. Mechanics said the leak is from the head or the block, but they're unsure.

  • 5
    OT: "driving 1.6-1.7 miles to work and back" when I've been lucky enough to have such a commute, apart from the really rainy days I've enjoyed the walk. Or in a town center you'd might actually get there faster by bike than by car. – Chris Stratton Apr 4 '18 at 16:15
  • if the light comes on, you are gonna blow , one of these days for sure – MichaelEvanchik Apr 4 '18 at 16:28
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    How could you be stranded, when you're at most 0.8 miles from your house or workplace at any given time? – stannius Apr 4 '18 at 16:44
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    I'll Probably get slammed for this, but if you are nursing it along adding fluid every day you can just use distilled water assuming you are past the freeze threat season. No point wasting expensive antifreeze. – agentp Apr 4 '18 at 21:38
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    Driving through town is probably the type of driving which taxes the cooling system the most. – errantlinguist Apr 4 '18 at 22:09
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It seems that you are only worried if the car will leave you stranded, not if it is bad for the car to drive around with (possibly) a bad head gasket.

Driving around with a shot head gasket is not optimal as some of the coolant may end up in the engine oil, but being a cheap car and driving short distances it probably is not that big of a problem. The car will probably not leave you stranded just like that, providing that you regularly check the coolant level and top up if necessary. Driving around with little or no coolant will seriously damage the engine eventually.

I'd just want to add one more thing (can't help it, im Dutch): why not just use a bike for such a short drive, weather permitting? It's not even a 10 minute ride and you'll have no worries about a damp car with foggy windows.

  • 1
    Given "waiting for windows to defrost", I'm pretty sure weather doesn't permit yet. – Joshua Apr 4 '18 at 15:52
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    You might find this crazy as a Dutch, but many (possibly most?) Americans don't own a bicycle. (I'm assuming OP is American because he drives a Ford and uses miles, but I realize that may not be correct.) – Apologize and reinstate Monica Apr 4 '18 at 22:19
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Provided you regularly check the coolant levels (with the engine cold) and top up then you ought to be fine. Running an engine without coolant is not ideal but I suspect there was some residual left in the system because you saw the overheat light. This is because the way the gauge works is to take the temperature of the coolant. With a completely dry system you get a zero reading because there is literally no coolant left.

One other thing I would advise, when topping up the coolant level, set the heater control in the cabin to full hot. This opens the heater valve and guards against the risk of trapping air in the heater matrix which can work it's way into the system and cause an airlock.

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    Your statement about the gauge reading zero is not accurate. The sensor will pick up the ambient temps within the coolant passage, whether there is coolant or not. It's just a thermal probe and will pick up air temps, steam temps, radiant temps, etc. Heat is heat and the temp sensor will pick it up regardless. The reading will most likely be a lot more erratic than if it resided in liquid, though. – Pᴀᴜʟsᴛᴇʀ2 Apr 4 '18 at 11:24
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    Yes, the gauge typically reads from around 50 degrees Celsius though and I have seen a "zero" (i.e. below 50) reading from an engine run without any coolant. You'll typically only get a warning light and high reading if enough coolant is in the system to cover the probe. – Steve Matthews Apr 4 '18 at 11:26
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    This hasn't been my experience. If an engine is overheating, it will show it whether it has coolant or not (as long as the sensor and everything else are functioning correctly). I wasn't suggesting it would "not read zero", I was suggesting the gauge and sensor will still function with or without coolant in the system. As I stated, it's just a thermal probe. It doesn't need coolant to pick up the temp and display it. – Pᴀᴜʟsᴛᴇʀ2 Apr 4 '18 at 11:35
  • @Pᴀᴜʟsᴛᴇʀ2 It does depend on where the sensor is fitted. If it is in the head, then it will likely react better out of coolant than if it is fitted elsewhere. Because there is no coolant circulating, the block/head could get to some seriously high temperatures before the mass surrounding the sensor started to heat up. Any hot air/steam that is pushed toward the sensor will likely be cooled by the cooler metalwork surrounding sensor not mounted in the head. Do you agree? – HandyHowie Apr 4 '18 at 11:41
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    @HandyHowie - If the sensor is outside of the engine it self (ie: radiator), I'd agree it wouldn't report very well. However, the temp sensors are located within the coolant loop inside the engine. Air/steam (remnants of what's in the cooling system) will transfer heat to the sensor, albeit not as well as coolant, but it will still transfer. For the most part, whatever is in there is going to get heated by the surrounding metal that is the engine. It doesn't take long for the heat within those chambers to build as the engine itself heats up. – Pᴀᴜʟsᴛᴇʀ2 Apr 4 '18 at 12:30
1

I am guessing you have a blown head gasket.

This causes:

  • Coolant to disappear.
  • Coolant to overheat.
  • Bubbles in your cooling system, so the heater won´t work properly.

Go to your repair shop and have them make a co2-test of your coolant. If there´s co2 in your coolant that´s the head gasket.

If you want to keep driving it until it dies, don´t full throttle it and don´t rev too high. I don´t recommend it though - having your motor blow up while driving is no fun!

1

Short answer, no and yes, running the car without coolant wont affect the car. Running the car while excessive overheating will damage the vehicle, components, and in worse case scenario, hurt someone due to an engine seize or fire.

When the car overheats, you run into the risk of seizing the engine. This normally wont happen while driving, but it depends on the temperature of the engine, it will tend to stutter if it gets too hot and shutoff. Be warned you may warp your pistons, or damage critical components before it seizes, extremely dangerous. If it gets to hot and seizes while running.... Well, let's just say I hope you have insurance and a good lawyer. ( Depending on your state, knowingly operating an unsafe vehicle is illegal. ) If it is cold enough outside and the engine doesn't shut off or run in the red to long, you should be okay. If it is warm enough outside, instead of ruining the environment with leaking antifreeze, you can use water as a coolant. If exhaust is running white, cloudy, chances are it is a head gasket. I also seriously hope you aren't using 100% antifreeze as that in itself can cause harm to the engine and pumps. Check for percentages on the bottle.

Small side note. Keep a smell out for sweet smells, often associated with coolant. To check for leaks put a white clothe under the front of the car when it is parked. Will give you an idea, if it is an idle leak.

P.S. Weather pending, 1.6 miles is about half hour walk.

  • Very good point about knowingly driving in a scenario where loosing the engine could be dangerous--i.e. harder steering and difficult breaking catalyzing an accident. – elrobis Apr 6 '18 at 15:16
1

I had that kind of issue long time ago, but with a smaller car. As long as you park the car and let it cool down whenever the temperature rises over 75% of the threshold you won't have any problem. Do not let the gauge reach the red mark. Additional hits:

  • Avoid drive with heavy traffic, because your only coolant will be the wind reaching the car.
  • Beware of hot days, it will increase temperature faster.
  • Do not accelerate too much the car, keep low the revolutions.
0

rAssuming you're past hard freezing spells for the season, you should at least refill the radiator with plain water before you set out for the day. At this stage your engine is pretty much gone, so any further corrosion from using plain water is going to have a lot less impact than actually running the engine dry. Your heater will not work if your engine is completely dry, and you won't be spewing toxic antifreeze all over the place.

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If you drive for a very short time with very low coolant, such as 30 seconds or maybe up to a minute, it won't harm anything. Long term frequent short trips only use is bad for an engine for other reasons though.

Ford has been using cylinder head temperature sensors since before 2004, so it should show the correct temperature even if there is no coolant circulating. That doesn't mean that racing it until the temperature gauge shows hot is okay. Without coolant hot spots could exist in the head.

Have you considered trading it with someone who can fix it for another car that has a working engine? Yours probably has a bad head gasket, and you're frequently mildly overheating the head, and getting coolant in places where it shouldn't go.

If you really want to keep driving it as long as possible until you junk it, you could disconnect half of the fuel injectors and disconnect the oxygen sensors. That will make it run like limp mode where it will take significantly longer to overheat. Disabling the cylinder that is leaking through the head gasket can reduce its ability to interfere with the cooling system. But you could be getting coolant in the cylinder, so make sure you're using real coolant and not just water since water could rust the piston.

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