Like the thermostat in your house, the thermostat in your car is responsible for maintaining the temperature of your engine. It does this by controlling the flow of coolant that goes through your engine and then back through the radiator. When your thermostat is working properly it opens and closes as required to either let coolant flow or stop the flow of coolant depending on what temperature your engine is currently at.
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Unfortunately, sometimes your thermostat can get stuck in either the open or the closed position. If you are driving your vehicle and the thermostat is stuck in the open position, it's definitely going to cause some problems for you. When your thermostat is unable to properly close when it needs to, the flow of coolant will be unrestricted throughout your engine. While that may not seem like a problem at first, it definitely can be.
What Happens When Your Thermostat is Stuck Open?
Under normal conditions the thermostat in your vehicle should be able to open and close as needed for the life of your vehicle. The thermostat isn't generally something that wears out, but any part of your vehicle could technically fail on you unexpectedly and the thermostat is no different.
Normally the thermostat works with a very simple mechanism. There is wax inside your thermostat that, when it reaches the right temperature of around 180 degrees Fahrenheit will begin to melt. When the wax melts it releases a rod or spring that presses down to open a cylinder or piston. So when it's hot, the valve opens, and when it cools down again the wax solidifies and the valve closes, restricting the coolant from that point. It continues to do that as the temperature fluctuates in your engine part of a system of maintaining the ideal operating temperature for your engine
If something goes awry in your engine, then it's possible your thermostat can get stuck in the open position. This could be caused by some kind of build-up of debris, grease, dirt, or some kind of corrosion that prevents it from closing properly. Some thermostats are designed to fail in the open position if a part of the device breaks. This is considered more desirable than feeling in the closed position because that would prevent coolant from circulating and your engine to overheat. It's easier to deal with the engine running too cold then it is to deal with one that runs too hot.
In the open position, coolant will continue to circulate through the engine to the radiator and back. Why all this is what you want going on when your engine is too warm, it becomes a problem when your engine is cold.
Your car is set up to warn you if it's running too hot and most drivers are aware of the dangers of an overheating engine. However, when your car runs to the cooled, we don't often consider that to be a problem. In fact, it's not healthy for your car to be running with a cold engine all the time either.
If your car is unable to get up to temperature, you're going to suffer in terms of gas mileage. A colder engine can cause the fuel to condense on your engine’s cylinders. When that happens It burns less efficiently, you end up heading to the gas station more often than you should.
Additionally, your car is designed to warm up quickly and efficiently. when that doesn't happen because the valve is open, the ECU, which is your car's computer, will cause you to burn more fuel because it's trying to get your car warmer during the warm-up cycle. This happens every time you turn on your car when it intentionally burns rich, which is to say it uses more fuel, in an effort to get your car up to temperature faster. An open valve means it cannot do this at all.
If this continues your car will stay in the warmup cycle all the time. That means you'll constantly be burning a rich fuel mixture lowering your fuel economy but it also means you're going to have carbon buildup inside your engine and if it gets bad enough you'll have unburned gasoline making its way into the exhaust system. That can end up destroying your catalytic converter. The catalytic converter is an important part of your car's exhaust that prevents pollution from being sent out into the atmosphere. It's not even legal to drive a motor vehicle with a properly functioning catalytic converter, and if yours is destroyed because of excessive buildup from your thermostat not working properly, you're looking at anywhere from $900 to $2,500 to get a replacement catalytic converter. That's a pretty steep repair bill for a problem that could have been easily prevented.
Cost of Repairing an Open Thermostat
Replacing a thermostat in your car could have a range of potential prices. Like most repair jobs, this one really depends on the make, model, and year of your vehicle. High-end vehicles tend to have more expensive thermostats in them and the cost of replacing them will set you back quite a bit more. For instance, a Jaguar XJ could end up costing you about $500 for a thermostat repair job from the mechanic.
Typically, however, for most cars that are on the road, you're looking at about $200 to $300 to get your thermostat replaced if there's a problem with it. It can definitely go lower than that as well, and the cost of a thermostat replacement for a very common car like a Toyota Camry could be between $130 and $165.
The cost of replacing your thermostat is much more related to labour rather than the actual technology being used. A new thermostat can be surprisingly cost-effective compared to many parts that you might need to buy for your car when they go wrong. You can buy a new thermostat on a site like Autozone.com for as little as $12. Of course, others can be as expensive as $255.
Can I Repair My Own Thermostat?
If you're looking to save some money on labor costs, which as we've seen can be pretty considerable for a job like this, you couldn't take on the task of replacing the thermostat yourself. All things being equal it's not that complicated of a repair job.
When it comes to do-it-yourself auto repair so we would consider this one a fairly beginner level job. If you're comfortable doing things like changing out your own oil filter, changing a flat tire or that sort of thing then the task of replacing a thermostat shouldn't be too difficult for you either.
The hardest part involved in this task is knowing that you have the right size thermostat replacement, and just locating where the thermostat is in your engine in the first place. There's no standard layout from one model of vehicle to the next, so if you can't see it right away you might have to refer to what engine diagram or your owner's manual to figure out what you're looking for.
The most important thing is to make sure you've got the exact right thermostat that fits your vehicle. As we’ve seen on AutoZone there are hundreds of different thermostats out of there, and if you get the wrong one it's definitely not going to fit. Fortunately, AutoZone can let you search by make, model, and year so you'll be able to get the right one.
In terms of replacing your thermostat yourself, there are definitely some handy guides on the internet that can walk you through the process to make sure you get it done right. If you want to take the easiest route, the best thing you can do is check out some of the videos online made by professional mechanics that show you step-by-step how to get it done. These are exceptionally helpful, and you get to see in real-time the entire process. Often it is easier to follow along with a video than a written guide if you're not sure about what you're doing.
Fortunately, getting it done on your own is not that difficult and doesn't require an abundance of tools either. If you want to replace your own thermostat you just need to make sure you have the following items on hand before you begin:
- The new thermostat
- Socket set
- Some cleaning rags
- Hose clamp pliers
- A drip pan
- A scraper
- Gaskets
- Sealant
- Coolant
Once you have all the materials you need to swap out your thermostat, there are only a few steps to get it done.
- Remove Your Old Thermostat: You'll be able to find your thermostat near the top of the engine. You can check out the manual to find out exactly where it is in your particular make and model of vehicle. It will be attached to a gooseneck housing that connects to the radiator. There should be two or three bolts that you need to remove to get the job done as well.
- Remove and Clean the Gaskets and Mounting: You can use the scraper at this point to remove the old gasket and sealing compound from around the gooseneck and the engine surfaces. Get it cleaned off as well as you can, dry it off with the rag.
- Apply the Sealant: Put some sealant on your new gasket and install the thermostat and new gaskets in place. You might have to hold it in place for several minutes to confirm the seal. Apply a bead of sealant around the new thermostat once it's sealed in place to ensure everything is watertight.
- Add New Coolant: Top off your coolant levels to the level indicated in the coolant tank and you should be ready to go. Start your vehicle and let the engine run for about 15 to 20 minutes to get up to normal temperature and ensure that you have a warm engine rather than a cold one at this point. If everything is warmed up, then the problem is definitely your thermostat and you have fixed the issue. If it's still running cold for some reason, that you have a deeper issue and you may need to take it to a mechanic.
As you can see it's a fairly simple process to replace the thermostat in your vehicle on your own. That means you're going to save yourself quite a bit of time from taking it to the mechanic to get it done, and also potentially a considerable amount of money depending on how much you do if there was that cost you. If you're only paying about $20 for the thermostat for your vehicle, it's definitely a good idea to give it a try on your own. You're looking at maybe 20 minutes worth of Labor to take out the old one and put a new one in once you're sure of what you're doing so that's not too bad of a deal at all.
The Bottom Line
Even though your thermostat is a very simple piece of technology, you can't underestimate how important it is to the overall functioning of your vehicle. Without an adequately working thermostat you can suffer some severe engine damage in the long run. Most of our attention is focused on a thermostat that isn't able to properly regulate heat leading to the damage of an overheated engine. Because of that, a cool engine is often overlooked and is sometimes considered not to be a problem at all.
As we’ve seen, if you have an engine that runs cold all the time it can affect your bottom line. You're going to lose money on gas, and the performance of your vehicle will suffer as a result. There's also the fact that if you are driving on a particularly cold day, you're probably not going to be experiencing a lot of heat either which will make it both inconvenient and uncomfortable for you to deal with.
If you're finding that your engine isn't running as warm as it should, it's a simple matter to troubleshoot and get it fixed either by taking it to a mechanic or getting the job done yourself. There's no reason to let this problem go for longer than it should because you're just going to end up paying more money for gas and suffering a poorly running vehicle until you do. Save yourself the trouble and get it fixed as soon as you can.