Is your car’s temperature gauge going up and down? Well, we cannot ignore the fact that a car’s temperature gauge is important.
But why? It monitors the temperature of the engine, and the gauge ensures that the engine is working properly. The fluctuating temperature gauge triggers uncertainty and can be a cause of concern.
Nevertheless, understanding why the temp gauge goes up and down is a key aspect of car maintenance.
A fluctuating temperature gauge is an indication that your car needs a routine adjustment, environmental modifications (such as stop-and-go traffic affecting engine temperature), or has potential problems.
Before we go ahead with the causes of the fluctuating temperature gauge, let’s first understand how it works. Just like our body indicates with fever when there is some infection, the car’s temperature gauge plays the same role.
To ensure no harm and guaranteeing smooth working of your car, it is quite essential to ensure that your engine is working properly at its ideal temperature.
Fundamentally, the temperature gauge is a simple but important device that is usually mounted on the dashboard of the vehicle.
Giving real-time input on the engine’s temperature is its main purpose. The temperature gauge works on a straightforward principle: the needle adjusts to the engine temperature as it fluctuates.
When everything is running well, the temperature indicator shows that the engine is running within the permitted temperature range. The moments when the temperature gauge goes up and down, however, are what catch our attention and make us confused.
Effective car maintenance requires an understanding of why the temp gauge goes up and down while driving.
What Is The Engine Temperature Gauge?
On your dashboard, you’ll find the engine temperature gauge. It’ll be one of the tinier dials. It has a needle pointing towards the colder side when the engine is off or only recently switched on. As the motor heats up, the needle will move to somewhere central on the gauge.
This should be the standard operating temperature. Actually, it’s the coolant’s temperature. It removes heat from the engine, dissipating it into the atmosphere via the common radiator.
It’s this needle that will fluctuate. You should always watch this while driving. Rising temperatures are often the first sign of many developing problems.
The temperature gauge sensor is typically located somewhere near the thermostat. Every manufacturer designs its engines differently, though. You may need to look around or make the most of online resources.
It sends an electronic signal to the ECU, altering the needle’s reading on the dashboard display.
Understanding The Temperature Gauge Movement
It’s important that you’re aware of what the normal temperature gauge movement range is. The temperature gauge starts is at the very bottom when the engine is cold because the minimum reading is usually set to 122 degrees Fahrenheit.
As you start driving, the internal combustion of the engine creates a lot of heat. Through thermal laws of physics, the heat of the engine is exchanged with the coolant in an attempt to equalize the temperature difference.
The gauge will start to rise until the engine reaches its optimal running temperature – between 180 and 220 degrees Fahrenheit. Almost every car temperature gauge has a clearly marked spot to signify the optimal temperature.
Once you park the vehicle and turn off the ignition, the internal combustion will cease and the coolant will stop flowing.
Because the coolant temperature sensor is located near the thermostat, it will cool faster than the coolant trapped inside the engine, and show a rapid decline in temperature.
The temperature gauge positions explained are what happens in a mechanically healthy vehicle that is driven optimally.
There are a number of reasons why the gauge might fluctuate, and in the next sections, we’ll go through all the reasons as to why that happens.
How the Car Temperature Gauge Works
The temperature gauge in a car is part of the dashboard instruments, designed to keep track of the engine’s coolant temperature.
It connects to a sensor located near the engine’s cooling passages, constantly measuring the coolant’s temperature and transmitting it to the gauge on the dashboard.
When everything’s working correctly, the gauge should stay within a certain range once the engine has warmed up. However, unexpected changes in temperature readings may suggest an issue with the cooling system.
causes of Temperature Gauge to go up and down
So, you ask, “What causes my car’s temperature gauge to fluctuate?” A plethora of factors are responsible for this anomaly. In most cases, some functioning parts of the cooling component might have gone wrong.
For instance, if you notice the temperature gauge fluctuates from normal to hot, you should suspect a fault-sensitive and inexpensive thermostat.
#1. Stuck-Closed Thermostat.
The thermostat regulates the coolant’s temperature before it returns to cool the engine. Though the thermostat is relatively cheap and replaceable, it can cause trouble for your car once it gets bad.
If it gets stuck and refuses to open, the coolant cannot flow to the engine to cool off the engine. This causes the engine to start overheating. When the engine begins overheating, the car temperature gauge can go hot and then return to normal.
After the 1980s, most cars that were manufactured had a closed-circuit type of cooling system with a reservoir tank that features a visible marking to determine the coolant level. It is, therefore, essential to regularly check this level to guard against coolant leakage.
If you notice a minute leak, you should rectify the leakage without delay because a low coolant level can cause your car temperature to fluctuate.
If your thermostat is partially stuck, then you are surely going to see your car temperature go down while driving. This is simply because the coolant is constantly being released into the engine, which causes the temperature to drop rather than climb up.
When a thermostat is functioning correctly, it only allows either warm or cool coolant to enter the engine, thus regulating the overall temperature of the car engine.
Though a partially stuck thermostat may not necessarily hurt your car, it can surely lead to increased fuel consumption. You are therefore advised to change the inexpensive thermostat than spend many bucks on your fuel purchase.
If the thermostat is functioning well, then the gauge may simply be broken.
#2. Engine getting Overheated.
Experts have confirmed that when your engine’s temperature goes higher than 2300F, your engine is said to be overheated.
If the temperature goes beyond 2450F, serious havoc might happen to your engine. This is more reason you should pay attention to an engine getting overheated.
Apart from a bad battery, one of the many reasons your car’s engine won’t start is that the car’s engine is overheated, accompanied by a significant loss of coolant.
The overheated temperature can further warp the cylinder head, thereby weakening the pressure the engine needs to start the car.
Over time, if the issue is not attended to, the pistons end up wielding themselves into the cylinder, which is catastrophic for your car’s engine. This means you will need a complete overhaul of a car engine.
Another similar problem you may notice in your car is that your car temperature gauge goes straight too high. Your first guess can be your engine is overheated.
Well, you are half correct! In this case, several reasons can lead to this sudden shooting up of your car temperature.
Your thermostat can be broken, or your car’s coolant level may have diminished. In either case, there is not enough circulation of coolant to cool down the running engine, thereby resulting in it getting overheated.
#3. Lousy Radiator Fan.
Closely located to the reservoir tank is the radiator fan. The fan is expected to pull air through the radiator when your car is not moving fast enough to draw in air.
Having a failing fan can be erratic and can cause your engine to get overheated. A lousy radiator fan can lead to a fluctuating temperature gauge.
#4. Head Gasket Blown.
Perhaps, in recent times you have discovered your car temperature gauge rises then falls. The possible cause of this irregularity is that the head gasket may be defective.
Located between the cylinder head and the engine block, the head gasket maintains internal combustion. It allows easy circulation of the coolant and oil throughout the engine for cooling and lubrication, respectively.
Due to serious engine overheating, the head gasket can become warped and cause the oil and coolant to mix together to form oil-coolant.
If the oil in the coolant circulates around the engine and the radiator, it can lead to the formation of clogs and sediments which cluster along the coolant passageways.
The clogs can prevent the flow of coolant, thus leading to an overheated engine.
Usually, an automobile with a defective head gasket cannot last longer than a month. The engine will be seriously damaged if the blown head gasket is continuously used without replacement. You are advised not to drive your car around when you have a faulty gasket.
A sure way to know you have a blown head gasket is when you notice white smoke coming from the tailpipe, unusual loss of coolant without a leak, and your engine getting overheated.
#5. Bad Radiator.
Most drivers experience an unpalatable experience because their car temperature gauge goes up while idling or in traffic. This can be frustrating and confusing for drivers. The most probable reasons can be a broken fan and a bad radiator.
The radiator regulates the temperature of the coolant. When you notice sludges form in the radiator, this means the radiator and its fan has gone wrong and need immediate replacement.
If the radiator is not changed sooner than later, the color of your coolant changes from yellow to rusty color, which means it has becomes inefficient for cooling down the engine. A better alternative to an iron radiator is an aluminum radiator.
The aluminum radiator boasts corrosion resistance, durability, and excellent heat output. Owing to their efficient thermal properties, aluminum radiators provide more heat than any other material.
A related cause for increased temperature while your car is idling is a bad radiator cap. When your car’s radiator cap is not properly sealed, air can penetrate into the radiator, producing air pockets in the heater core and radiator hoses.
The result is that the car engine will begin to overheat since there is no stable temperature of the coolant throughout the engine. Symptoms of a failing radiator cap include an overflowing coolant reservoir, collapsed radiator pipe, and leakage in the coolant level.
#6. Faulty Cooling System.
So, if you find your car temperature gauge rising but your car is not overheating, there might be a few reasons: a bad radiator, reduced coolant level, a defective thermostat, or a faulty water pump.
A bad water pump can also cause the car’s temperature to move straight too high. A water pump pumps coolant through the cylinder head and engine block, thus regulating the engine’s temperature.
When your water pump develops a fault, it will be unable to pump coolant throughout the engine. This invariably leads to engine overheating.
If there is no quick intervention, the cylinder head can become warped, and the head gasket gets distorted, leading to a sudden increase in the car temperature. Often, this can cause the engine to seize up or refuse to start.
A common reason your car temperature gauge goes up and down, and no heat is emitted, is that your cooling system is faulty. You may want to check out clogged components such as the heater core, radiator hose, coolant level, thermostat, or water pump.
The coolant passageway might be blocked with sediments or rust. You should consider replacing the rusty components.
The primary reason your car temperature gauge goes up and down while driving is simply because a component in your cooling system is not functioning correctly.
This could be the thermostat valve, radiator hoses, radiator fan, temperature gauge, or the coolant itself that circulates around and cools off the engine.
You can either invite a professional car mechanic to fix these issues or easily replace most faulty components by yourself.
Diagnosing Fluctuating Temperature Gauge Issues
To ensure the proper working of the car, it is a must for you to understand why the temp gauge goes up and down while driving. Let’s have some know-how.
#1. Visual Inspection.
Check if there are puddles or dirt beneath the car or around the connectors or the hoses. This can lead to fluctuations in the temperature gauge.
#2. Temperature of the Coolant.
If there are low coolant levels, they may cause the temperature gauge to fluctuate because they interfere with the cooling system’s efficacy.
#3. Operation of the Thermostat.
There may be a fault of the thermostat as well. To check if it is working properly, know that a properly working thermostat should stabilize the gauge by opening at a certain temperature. If the gauge continues to fluctuates, the thermostat must need a replacement.
#4. Examination of the Radiator.
Some clogs or debris in the radiator impedes the thermostat to cool down.
How To Fix If Car Temperature Gauge Goes Up And Down
#1. Replace Thermostat.
On average, you will spend $125 to $300 to replace the car thermostat. However, it’s not a difficult job to do yourself.
Start by locating the thermostat. It is probably located where the top radiator hose joins the engine, but it could also be on the bottom hose. Remove the clamp and catch the coolant in a bucket underneath.
Remove the old thermostat and put a new gasket in place. You can now put on the new thermostat, replace the parts, and fill the system back up with coolant.
#2. Fill Cooling System.
A professional coolant flush will cost between $65 and $150 on average. However, this is another job that can be done at home.
Drain the radiator and fill it back up with distilled water. Let the vehicle run for ten minutes. Shut off the engine and drain the dirty water from the system. Put fresh coolant into the system, mixed as recommended by your automaker.
#3. Bleed Cooling System.
You can also bleed the cooling system if you notice air getting trapped. Take off the radiator cap and fill it with coolant as much as you can. Start the engine and turn the heat on high with the fan on low.
Continue topping off the coolant as the levels drop. Loosen up the bleed valves and rev the engine a few times to circulate the coolant. Do this until the temperature stops fluctuating.
#4. Replace Temperature Gauge Sensor or Gauge.
The cost to replace the temperature gauge sensor should be between $200 and $450. You could need to change the coolant temperature sensor on the top or side of the engine. There’s also a chance that the gauges themselves are to blame.
Make sure you perform proper diagnostics before you start replacing parts. Otherwise, you could waste money on unnecessary repairs.
#5. Replace Computer Module.
This is the most expensive repair of all the options. On average, a new Engine Control Module costs about $300 to $1,500 for parts and labor.
A good code scanner should reveal if there’s an issue with the Engine Control Module. You may also notice other unusual symptoms as this central hub starts to fail.
Preventative Maintenance Tips
Regular maintenance can keep your car’s temperature steady.
- Regular Coolant Level Checks: Checking the coolant level every few months can prevent overheating.
- Inspecting Belts and Hoses: Ensure belts and hoses are in good condition to avoid unexpected coolant loss.
- Thermostat and Radiator Maintenance: Routine inspections help catch early signs of wear, preventing sudden temperature changes.
FAQs.
Q: What does it mean when your temperature gauge goes up and down?
This simply means that your engine is overheated. An overheated engine can be caused by several factors.
These factors may include leakage in the coolant level, a clogged radiator hose, a defective thermostat, a bad water pump, and failed radiator fan.
The car temperature gauge might also be the culprit if it has developed a fault.
Q: Is it normal for a car temperature gauge to fluctuate?
Typically, a car temperature gauge is built to last for a long time and slowly rise from cold and stay in the middle.
So, when you see the indicator starts fluctuating, you should be quick to check out what exactly is wrong and rectify it without delay.
Q: Should my temperature gauge be in the middle?
The car temperature gauge slowly moves from cold to the middle after driving for a few minutes.
The average level of the temperature gauge, when your vehicle is fully working is about the center. Anything apart from this level calls for swift attention.
If the gauge remains in the cold after the engine has run for a very long time, it could mean the car gauge is broken or the thermostat is partially stuck.
However, if the temperature gauge goes too high, the engine is overheated and likely caused by a faulty cooling system or warped head gasket.
Q: What does it mean when your temperature gauge stays cold?
Your temperature gauge ordinarily stays cold until your engine has run enough. Then, it starts climbing up slowly. If the temperature gauge is stuck in the cold, the car gauge could either be broken, or the thermostat has gone faulty.
If the thermostat continuously releases coolant to the engine, the engine becomes cool and can affect the fuel economy and the car’s performance.
Q: Where should your temperature gauge be on your car?
Typically, there are markings for hot and cold on the temperature gauge. If you observe very well, you will also see a marking in the middle.
This middle marking indicates the average temperature for your car. The needle of your car’s temperature gauge slowly moves after you engage your engine.
After a long distance, if your car is behaving normally, the car gauge stays in the middle. Ideally, the temperature for your vehicle should be between 195 degrees and 220 degrees, which is about the middle marking of the gauge.
Final words
Your car temperature gauge might be proving funny as it fluctuates erratically. Common reasons for this irregularity include a lousy radiator, defective water pump, leakage in the coolant level, and faulty thermostat. Also, a blown head gasket can be a chief culprit.
You must replace any defective component as soon as possible to avoid further damage to the car’s engine if you notice your car’s temperature goes up and down. You can replace them by getting the right tools.