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Steam Coming Out of My Car's Hood? How to Diagnose Overheated Engine

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Oh man, this thing's overheating. Looks like we're gonna have to check this out. Hey friends, it's Len here from 1A Auto. Today I want to talk to you about some of the things that I would think about if I had an overheating condition on my vehicle. Let's say you're going on a road trip, you're super excited, you start driving down the road, and you see that needle go shooting way up high. Well, that's obviously not a good thing. So, I wanna talk to you a little bit about it. Let's get started.

So, firstly, we're gonna talk about some symptoms, symptoms of what you might notice if you had an overheating condition. Well, firstly, of course, like I said, you might notice that temperature gauge goes shooting up all the way into the high range. Obviously, like I said before, that's not a very good thing. You might also notice that there's steam or even smoke coming from underneath your hood. Maybe sometimes it comes billowing out from the hood/grille area of your vehicle or even down near the ground and then comes rolling out. That's very bad as well. Other things you might happen to notice there's a sweet smell in the air. That's because of the coolant. As coolant vaporizes, it goes up into the air and the chemicals inside of the coolant are vaporizing as well and that creates that sweet smell. So, if you smell a sweet smell coming from underneath your hood, well, you know that you have a coolant leak somewhere. One last thing, if you got drips on the ground, and it looks like it's coolant, it probably is.

So, let's go over some steps to take in case you have an overheating condition. What you first need to do is get off the road, you wanna be as safe as possible. Once you've done that, make sure you turn your vehicle off, you don't wanna leave the vehicle running while it's overheating. Put the key back in the on position then put on your blower motor. That's gonna draw heat away from the engine compartment. So, that's gonna be very important and it's gonna help you out in the long run. Once you've done that, if you don't see any steam or any smoke coming from underneath your hood, go ahead and carefully open it up. Just be careful because there could be something that might come up in your face. Obviously, if you have hand protection or eye protection, it might be a good thing. Anyways, lift the hood up and let all the heat dissipate before you continue.

So now once your vehicle's cooled down enough to the point that you can get safely underneath the hood and you're not worried about it being too hot, I would come right over and out I'll check the cooling system. For this one, in particular, it's a sealed unit, and it's all one pressurized system. So, it doesn't actually have a radiator cap and a separate overflow tank. For this one, in particular, I can just see right here, it has a little area where it tells me where it should be. And then, of course, I can see down here where it is. This is a little low, it's not necessarily gonna cause an overheat condition, but it is something to pay attention to. If you do happen to notice that your coolant is low, that's a probability of why you're having an overheat condition. But you also need to think of why your coolant might be low because it shouldn't just disappear.

Whatever the case may be, never open your cooling system if the system's hot. As you can tell right on this cap, it even tells you so. The reason why your coolant condition and level is so important is because the coolant serves a couple different functions. If the temperature is hot, it's supposed to cool down the engine. If the temperature outside is cold, it needs to make sure that the engine doesn't get too cold. Because if it's cold outside, below 32 degrees, water is gonna freeze. If you don't have enough concentrate mixed in with your water, obviously, that's not gonna be good. If you have too much concentrate mixed in with the water, then you're not gonna have enough heat dissipation. So, what's gonna happen is your vehicle is gonna be able to overheat, and it's not gonna remain inside the optimum operating temperature as it should. We don't only wanna talk about the level of the coolant, we also wanna talk about the condition of the coolant. It's not gonna be the easiest thing to see if it's inside of the system, such as your radiator, or even the overflow. But you do kind of need to gauge that by taking a look at it. You can use something as simple as a turkey baster or whatever you might happen to have, a screwdriver or something that you can draw some fluid out, and then maybe try to get it up into a cup. Once you have it in a cup, you'll have a better look at what's going on. We'll look right here. This is the fluid that we pulled out of the cooling system on this vehicle. This is what the coolant should look like. As you can tell, they're very big difference. You can't just go by looks though you have to actually test it. You can do that with something as simple as a coolant or battery refractometer. It's a nice tool, you put a little drip on it and what it's gonna do, it's gonna give you a chart and it's gonna tell you the freeze point of the coolant. And the coolant that's inside the vehicle actually tests off the chart at approximately negative 60 for our freeze point. When you have perfect coolant or 50/50 mix of coolant and water like it should be, it should be approximately negative 32 for our freeze point, which in most places, that's probably more than enough. Of course, if you're living in the arctic or someplace super cold, you might wanna use a different mix of approximately 60% coolant and 40% water. With that said, just looking at 'em, you can tell that this one isn't really in the best condition, it's a little old. Test it, if it looks like it's good, great. If it's not good, well, then you're gonna have to flush it and put in some brand new coolant.

Okay, so let's go with the assumption that you found that your coolant was low. Obviously, maybe you're sitting on the side of the road or wherever you are you're having the overheat condition and you can't necessarily test the coolant. But like I said, we're assuming that it's just low. There's a couple things that could happen. Reasons why it might be low, would be of course if you have an external coolant leak someplace such as maybe a radiator or your water pump or something like that, which I'll get into a little bit later. Or maybe you have an internal coolant leak, which would be something where your coolant is actually leaking into your cylinders, getting burnt up inside that combustion chamber and then of course getting shot out the tailpipe and you're gonna probably have like a white smoke. Other than that, reasons why your coolant could be low, is just because the coolant is old inside there, the water that's supposed to be mixed with the concentrate has been evaporated out at some point. And so, the coolant's just overstrong and it's gonna be low at that point.

If you do have to add a little bit of coolant it's great if you can find some 50/50 pre-diluted coolant. Of course, you're gonna wanna find the coolant that's meant for your vehicle as well. Otherwise, if for some reason you find coolant that comes concentrated, you're gonna need to go by the chart back here, but overall in most conditions, you're gonna wanna go 50% concentrate, 50% water overall.

With all that said there are other things that could cause an overheat condition such as your radiator. Your radiator is gonna have a whole bunch of cooling fins on it. Those cooling fins are supposed to cool down the areas where the cooler is gonna be flowing through your radiator. If for some reason the cooling fins are damaged, where they're may be peened over or they have a whole bunch of debris in or around them it's gonna cause an issue and you might have an overheating condition.

Now, on the engine compartment side of that radiator, you're gonna need to have some sort of fan that's gonna be able to draw air through the radiator cooling fins. Some vehicles are gonna have an electronic fan that looks like this, which of course will be powered by the car's computer. Other vehicles are gonna have a thermal fan clutch that is pretty much just attached to the water pump. In both cases, if the fan doesn't work when it's supposed to, of course, you're gonna have an overheating condition.

Speaking of water pumps, here's one right here. It's not the same for every vehicle just so you know, but it is one that I have out. This is the area where that clutch is gonna be on for the fan. And then this is the pulley that your drive belt is going to be spinning. And as it spins this, inside of this location, inside the water pump there's an impeller, that's gonna draw coolant from one side, pull it around through, and then put it out through the other side. The reason why it does that is because it has to be able to make a constant flow of coolant through your cooling system as it needs to cool down.

A couple other things to think about that go along with the water pump issue is of course it's powered by your drive belt. With that in mind, if your drive belt is in poor condition, maybe it's coming apart or even fell off, obviously, that's gonna be an issue. Or maybe your serpentine belt tensioner right here is too weak and it's not putting enough pressure from your serpentine belt on this pulley, in which case, it wouldn't be turning this fast enough and of course, you're gonna have an issue.

Something else that's gonna prevent your coolant from flowing as it should could potentially be your thermostat. A lot of times your thermostat's gonna be inside of a house and that looks like this. And it should be pretty much attached to something that looks like this, which would be one of your coolant hoses. As you can tell, it's got a nice area for it. If you were to take it out of the housing, you're gonna see that there's a springed area. If I was to put this inside a steaming hot bowl of water, what would you notice would happen would be this would start to move and it would make it so the valve on the inside of the thermostat itself opens up and it allows coolant to flow through your cooling system. The coolant shouldn't flow until your engine actually gets up to operating temperature.

Now let's talk about the coolant temp sensor. If the coolant temp sensor isn't functioning properly, it's not gonna be able to communicate with the brain of the car or the computer. If the computer doesn't know what the temperature of the coolant is, it's not gonna be able to turn on the fans as it should. And of course, it could also change things such as your fuel trim, so you might notice a runnability issue. So, a coolant temp sensor is definitely something to keep in mind if you have an overheat condition.

Speaking of your coolant temp sensor, you also wanna make sure you check the wiring. Because, of course, if you have any wiring that looks like maybe something chewed it up or it's just broken or frayed or anything like that, that could cause an issue as well.

Something else to pay attention to would be, of course, if you have a blockage in your cooling system. Maybe your coolant's some poor condition and you happen to notice that there's debris or something inside of it for some reason. If anything's clogging up your system or even you notice that one of your hoses is pinched or collapsed. Obviously, that's not gonna be good in any way and it could potentially cause an issue. Some other places you could think about would be maybe your heater core hoses which would lead to the firewall back there, which in turn would lead to the heater core which is behind your glovebox. That also leads me to mention that there is other areas that you could have leaks. Places that you might have leaks could be something such as the radiator as I mentioned before, your water pump, any of the areas where your hoses connect onto something, areas on the hose that might have rubbed on something, or of course, your thermostat or any gasket that has to do with your cooling system.

Something else to think about, if n the front of your vehicle towards where the radiator is, if you have any type of air dams that are supposed to funnel air into where the radiator is, if they're not connected the way that they should be, there's a possibility that they could flap over like this, which of course, will block a lot of the radiator, especially if both of them happen to do this. And it's gonna restrict air from being able to get in here because it's not getting funneled the way that it should.

To spare you the hassle of getting down on the ground I'm just gonna mention it. If you have a skid plate or one of those plates that goes underneath your engine compartment on your vehicle, there's probably a reason why the manufacturer put it there. So, if for some reason yours broke, got misplaced, or maybe you just left it off for some reason, it's probably not the best idea. The reason for that is because the manufacturer has your vehicle set up for perfect aerodynamics and course airflow going in and out of your engine compartment. So, it's gonna help cool your engine.

And lastly, if you're towing something that's super heavy, maybe up closer to the upper range of your tow capacity of your vehicle, obviously, you're gonna be putting a lot of stress on your engine, which of course, would cause more heat. So, if you're driving around in the summer heat, and you're going up a big hill, and you're towing 10,000 pounds behind you, or whatever you're towing, obviously, it's a lot of strain on the engine, you're gonna produce heat and if you don't have a good cooling system, you're gonna have issues.

Now with all that said, overall, an overheating condition shouldn't be the end of the world, assuming you take care of it ASAP. Of course, if you keep driving while your temperature gauge is saying that it's shooting up too high, you could potentially cause detrimental damage to your engine. But we're gonna go with the assumption that you caught it in time, I gave you a couple different places that you can go ahead and pay attention to to take a look. Overall, mechanical parts fail over time, that's just what's gonna happen. Fluids need to be changed over time. So, go ahead and get inside your glovebox, find your owner's manual, check out your service interval. If for some reason you're behind on keeping up with your maintenance, you're gonna wanna play catch up before of course, you have this particular issue.

Okay friends, I sincerely hope you're not having an issue with an overheating condition. If you are, hopefully you learned a little something about this video. And if you did, leave it in the comment section below because I'd love to hear from you. While you're at it, if you enjoyed the video smash on that like button for me, it would mean the world. Feel free to subscribe and ring the bell that way you can be kept up with all of our latest content. Thanks.

Thanks for watching. Visit 1aauto.com for quality auto parts shipped to your door, the place for DIY auto repair. And if you enjoyed this video, please click the subscribe button.


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