Too Cold in Your Car or Truck 4 Reasons Why It Wont Warm Up

All right. Almost time to get out of here. Let's remote start the truck, give it a couple of minutes, and then we'll get out of here. Still cold in here. Still cold air, unbelievable.

Hey, friends, it's Len here from 1A Auto. So, maybe you're having an issue with heat inside of your passenger compartment inside your automobile. I kind of want to get into some of the reasons why you might have this issue. So, let's talk about it. Firstly, the way that I want to start off is to let you know how this is actually going to work. Essentially, the way that you're going to get heat inside of your passenger compartment is due to the fact that as your engine's running, it's heating up. At the same time as it's heating up, you also have coolant or antifreeze that's going to be flowing through the system. It's going to get circulated around by that water pump. So, as your engine's running, it's going to be turning a belt, which, in turn, turns the water pump. The water pump is going to circulate that coolant around and through your engine, warm it up, and then, of course, it's going to get blown through over to your heater core. The heater core is generally going to be located inside of your passenger compartment on the passenger side, usually. And, of course, that's going to be the area where the air from your blower motor is going to get pushed through, warmed up, and then, of course, it's gonna warm you up so you're nice and toasty inside that passenger compartment.

Now, the first thing we're going to talk about is coolant/antifreeze level and condition. If for some reason your coolant level is low, maybe there's a couple reasons for that. Potentially, you could have a leak someplace or maybe you even have an area where maybe your radiator cap is venting a little bit, which essentially means you have got a little bit of steam coming out of here. Another reason why your coolant might be low is something that you can't even really see and that's going to come down to an internal leak. Essentially, what I mean by that is you got a whole bunch of gaskets on your engine. Essentially, those kind of keep things apart from each other, like cooling passages and cylinders and everything like that, where your pistons are. If the gasket's in poor condition and maybe it's leaking in any way, you could potentially be getting coolant burnt up inside your engine and then getting shot right out the tailpipe. If that's the case, you're not necessarily going to be seeing the coolant dripping on the ground like you would see with any other leak, you would be seeing it come out the tailpipe, and generally, it's going to come out as a white smoke.

If you have low coolant inside your system, that's obviously going to cause issues. The coolant's low, that means that there's air in there as well. If something like that gets trapped inside your heater core, you're going to have a discrepancy where the temperature of the heater core isn't going to be as warm as what maybe it should be. So, your blower motor is going to be trying to push air through that little heater core/radiator-type looking thing, and that's going to cause an issue where you're just getting either warm air or even just cold air. So, now we need to talk about the coolant condition. If you were to look down here, you can look inside this bucket and you're going to see that this coolant is in very poor condition. Over here, we have a cup of new coolant. As you can tell, there's no contaminants inside of it. We have nothing floating around. And, of course, this is going to have a much better freezing and boiling point.

Typically, when your coolant breaks down, it's going to change the freeze point and the boiling point of the actual chemical itself. You could end up having an overheat condition or even if it's bad enough, you could have a freeze-up condition. Coolant overall comes in a bunch of different colors. You might find green, yellow, pink, red, and anything like maybe even blue if you look around hard enough. Essentially, what I wanted to show you was that the new coolant does not have anything inside of it. The old coolant, if you were to just kind of stir it around a little bit, I'm going to see that I got a whole bunch of floaties moving around inside there and a whole bunch of contaminants. This is no good for your system.

Now, the second thing we're going to talk about is leak stopper. A lot of times when people have a leak in their cooling system, maybe they see a drip someplace or maybe even they see that white smoke coming out of the tailpipe, that's going to cause them to want to fix that leak. Sometimes maybe that part costs a little bit too much money or maybe they just don't feel like doing it at that particular time, so they go with something that you can purchase pretty much anywhere, and that's called a leak stopper. These leak stoppers are gonna come in different types. You can get it inside a little bottle with a little shake it up and it's got a whole bunch of little particles inside of it or even you can get those little tabs. Basically, you have these tabs, you put them inside some coolant, they kind of break up a little bit, dissipate, and it causes all these little crunchies that kind of float around. As that stuff's getting circulated around inside your cooling system, it's trying to find the leak. It's looking as hard as it can. Maybe it finds the leak, maybe it seals it up for a couple of minutes. The problem with this though is that it doesn't only stop there. It doesn't know this is my only job, go to the leak and everybody pile up here. It kind of goes to the leak. It stops there. That's great, but there's a whole bunch of the rest of it just floating around inside your system.

It's going to sit places, it's going to go places it shouldn't, and, of course, it's going to wreak havoc inside your cooling system. Now, if I just go ahead and lift up on this, you can see that somebody definitely added some sort of leak stopper here. I've got a whole bunch of crunchies and crud that are built up right on this radiator cap. And if you were to look inside this area right here, you're gonna see there's a whole bunch more inside there. Now, this is just what I can see though. I can't see what's going on inside this engine. You have your water pump, you have your thermostat, you've got a whole bunch of other areas where coolant's going to be flowing through and it needs to be able to flow through without restriction. But if it's got this stuff all built up on it, it might not be able to function properly. And, of course, if you're not fixing the original leak/issue, you're kind of just causing another one because at some point the original leak's probably just going to leak again. And at that point, you're going to probably have to flush out your system pretty good because you're going to have all this crud inside there and you need to make sure you get it out of there.

Now, since we talked about leak stopper, I want to continue on to talking about blockages. And this one, in particular, is going to come down to your heater core. Like I told you before, your heater core is going to be located inside of your passenger compartment behind essentially the passenger side dash. Now, the heater core is going to look a lot like this. Yes, this is a radiator and this is much bigger than what a heater core is. But essentially, it's going to look the same except in a miniature version. It's going to be very small like this. If you were to look at this, you're going to see that it has very small passages where the coolant has to be able to flow through. Essentially, the coolant's going to go in through here, come shooting down through this whole area. It's gonna be much smaller like I said, on a heater core, and then it's gonna come out the other side.

Essentially, what's supposed to happen is when you go ahead and turn on your blower motor, it's going to be drawing air through the system, blowing it through this, and then coming out the other side. If these passages are clogged up by using a leak stopper of some store or even a contaminant inside the system, obviously, that's going to cause a restriction where the coolant isn't going to be able to flow through here to be able to warm it up. You're running that blower motor, it's just drawing cold air, blowing it through this, and then pushing it into that passenger compartment on you, "Ooh, it's a little chilly in here." Why is it? Well, because maybe the heater core is blocked up.

This is going to be something that's super common, heater cores block up, especially if you end up using any type of leak stopper. Now, a quick way that you can tell if your heater core has a block or not is to find the coolant hoses that lead through your firewall. The firewall in case you are wondering is the wall in between your engine and your passenger compartment. Super important, it keeps you safe. Essentially, there's going to be two coolant hoses that go inside that area. There shouldn't be any others. You find those cooling hoses and then you can either use a tool that looks like this, a little temperature gauge, these are great so, you don't have to touch the hose. You can gauge them both and make sure they're approximately the same temperature. Or, of course, if it wasn't too hot, you could reach down there with your hand, just be very careful not to burn yourself and just kind of give them a little feel. Make sure that they're approximately the same temperature. If you happen to find that the coolant hoses are different temperatures, maybe by more than 10, 20, or even higher amount of degrees, that's gonna more than likely tell you that you're having an issue with the heater core. Essentially, the coolant's supposed to go in, flow around through it, and then come on back out and make its way back through the engine/the radiator in the cooling system overall.

Now, another thing that I'd like to talk about for possible reasons why you don't have enough heat coming inside your passenger compartment could come down to temperature control issues. Typically, a lot of these can be found inside of the truck. Generally, you're going to have some sort of gauge or a switch that's going to be able to control how much heat or cool air is going to be getting pushed inside of your passenger compartment. If you're having an issue with the switch where it's just not telling the blend doors what to do, well, of course, that's going to be an issue. Essentially, as you turn that switch from hot to cold, the blend door should move and essentially it's going to move the channel so it can either get blown through the heater core, warm up the air, or just divert away from the heater core and keep the air nice and cool. That might work fine. That's amazing.

But the blend door might actually close off the channel that's making it so the air that's coming from the blower motor isn't getting pushed through that heater core, it's getting diverted away so it's just circulating cold air. Essentially, if the blend door is working the way that it should, maybe it could come down to a physical problem such as binding or it's broken in some way or even an electrical problem. Maybe the switch isn't working or a fuse issue of some sort or another electrical issue. That's going to cause the air to not be diverted through the heater core the way that it should and, of course, you're going to have cool air blowing throughout your passenger compartment.

Now, the next thing that I want to talk about is your thermostat. The thermostat on your automobile is going to be located on your engine typically inside a housing of some sort. It might even look a little bit like this. Now, the job of the thermostat is to make sure that your engine can get up to and remain at normal operating temperature. Essentially, what happens is as the coolant reaches operating temperature, it's going to make it so this valve can open up and it's going allow coolant to flow throughout the rest of the cooling system. Typically, what can happen is if your thermostat gets stuck in the open position, it's going to make it so your coolant can keep on flowing throughout your cooling system, including your radiator. What this will essentially do, especially in the wintertime is it's gonna make it so your engine can achieve the optimal operating temperature, and of course, your coolant won't be up to the proper temperature to be able to heat up the inside passenger compartment the way that it should. And if, of course, the valve is stuck shut, that's going to cause a restriction inside your cooling system. Essentially, it's probably gonna keep all the hot coolant in your engine and the cool coolant inside around your radiator and probably even your heater core, which would be essentially the reason why you're not getting any heat in there.

Okay, friends, so that's pretty much what I've got for you for poor heat conditions inside of your passenger compartment. Hopefully, you're not having this issue. If you are or maybe you've had it before, maybe there's something that you learned that I didn't go over in this video. You got something to say, leave it in the comment section below because I always love to hear from you. If you liked the video or you learned something, smash on that like button for me, it would mean the world. While you're at it, go ahead and subscribe and ring the bell. That way there, you can be kept up with all of our latest content. Thanks.