One fine morning, cruising on your way to work, and discover your car temperature gauge fluctuates inside.
You feel so confused and disturbed. And then there you are stuck, “How on earth will I troubleshoot this mechanical bug?”
Worry no more. That’s why we are here to assist you pinpoint this issue and providing a diagnostic answer.
Well first and foremost, your car temperature gauge is simply a dial which shows how hot or cold the coolant of your engine is. Under normal reason, gradually after you start off car’s engine and have traveled a distance, it should rise.
Well, the needle of your car temperature gauge can falter (up and down), this can be due to a number of things. Stay tuned as we go into detail below.
What causes Car Temperature Gauge to go up and down?
So, you wonder what makes my car temperature gauge fluctuate? A zillion things actually. More often than not, one or more functional parts of the cooling unit has malfunctioned.
If you notice the temperature gauge fluctuates from normal to hot, suspect a cheap thermostat that is sensitive to problems.
#1. Stuck-Closed Thermostat.
The thermostat regulates the temperature of the coolant before the coolant goes back again to cool off the engine. Although the thermostat is relatively cheap and easy to swap out, it can really give your car a run for its money when it goes bad.
If the thermostat becomes stuck, it will not open, hence the coolant will not flow to the engine to cool off the engine and the engine starts overheating. When this happens, the car temperature gauge can become hot and then return to normal.
Most cars made after the 1980s had a closed-circuit type of cooling system with a reservoir tank that has a visible marking to ascertain the coolant level. It is therefore wise to check this level from time to time to prevent coolant leakage. If you notice a minute leak, rectify the leakage straight away, since a missing amount of coolant can make your car temperature fluctuate.
If your thermostat is partially stuck, then you are surely going to see your car temperature go down while you drive. This is simply because some coolant is always being allowed into the engine so that the temperature tends to drop rather than go up.
When the thermostat is working as it should, it will only allow warm coolant or only cool coolant to enter the engine, thus controlling the total temperature of the car engine.
A partially stuck thermostat will not do severe damage to your car but surely, it will cost you increased fuel consumption.
You are therefore better off changing the inexpensive thermostat than to shell out a load of bucks on gas purchase. If the thermostat is indeed working properly, then possibly the gauge is broken.
#2. Engine getting Overheated.
It is generally agreed that once the temperature becomes higher than 2300F, your engine is overheated.
If it gets hotter than 2450F, and havoc befalls your engine. This is more reason you should not ignore an overheating engine.
Apart from a bad battery, one of many reasons why your car won’t start, is because the car engine is overheated, although it has lost coolant too much.
That overheated temperature can further warp the cylinder head, thereby robbing the pressure necessary for starting the car, respectively the car engine.
Over time if the problem is not looked into, the pistons end up welding themselves into the cylinder, that is, your car engine is doomed. A complete overhaul of a car engine is due.
Yet another problem close to this one is that your car temperature gauge goes straight too high. You may think your engine is overheated.
Well you are right, half wrong! In this case, there can be various reasons for the sudden shoot up of your car temperature.
Your thermostat can be defective, or your car coolant level lower. In either case, there is not enough circulation of the coolant to cool the running engine, resulting in it getting overheated.
#3. Lousy Radiator Fan.
Just next to the reservoir tank is the radiator fan. If for some reason your car is not traveling fast enough to pull air through the radiator, the fan is supposed to pull air through.
A failing fan can be erratic to the point that your car gets overheated. A bad radiator fan can also lead to a fickle temperature gauge.
#4. Head Gasket Blown.
Of late you have noticed that your car temperature gauge rises then falls. The likely culprit is that the head gasket may be defective.
The head gasket forms a seal between the cylinder head and block to form a seal for avoid leakage of combustion. It further helps the coolant, and the oil to pass through the engine for cooling and lubricating respectively.
The head gasket can warp if the engine vastly overheats. This can cause mingle of oil-coolant.
If oil in coolant courses round the engine and into the radiator, it can form clogs and sediments which cluster and pile up along the coolant passageways. Clogs can cause the coolant not to flow freely to caution you of an overheated engine.
Usually, an automobile having a bad head gasket can hardly makes a month. If a blown head gasket is used incessantly without replacement the engine will be knocked. You are told not to be driving your car around with a leaky gasket.
A sure sign you have blown head gasket is smoking from tailpipe, losing coolant without a leak, and an overheated engine.
#5. Bad Radiator.
Most drivers have an unpleasant experience when their car temperature gauge rises while idling or stuck in traffic, causing confusion and frustration. Most likely, this is due to a defective fan and radiator.
The radiator is what keeps the coolant temperature at bay. If you see sludge collection in the radiator, this would mean that the radiator and its fan was defective and will be needing replacement.
If the radiator is not replaced, the color of your coolant will change from yellow to rusty color which indicates it is no longer effective at cooling down the engine. A better option than an iron radiator would be an aluminum radiator.
Aluminum radiators provide corrosion resistance and durability along with exceptional heat output. Due to their thermal efficiency, aluminum radiators can achieve higher heat output than any other material.
An associated culprit to higher temperature while the car idling is a defective radiator cap. When the radiator cap is not TIGHT, air will enter the radiator thereby causing air pockets in the heater core and radiator hoses.
The result is that the car engine begins to overheat because there is no steady, stable temperature of the coolant throughout the engine. The signs of a faulty radiator cap would be the coolant reservoir overspilling, collapsed radiator pipe, or leaking coolant level.
#6. Faulty Cooling System.
So, if you notice your car temperature gauge rising but your car is not overheating, it could be a bad radiator, a low coolant level, a faulty thermostat, or a bad water pump.
Bad water pump: A bad water pump can also make the car move straight up to high. The water pump pumps coolant through the cylinder head and engine block of your car to control the temperature of the engine.
When your water pump has a fault, it will not be able to pump the coolant throughout the engine. This will most likely lead to the car overheating. If no action is taken quickly, the cylinder head could become warped, and the head gasket gets distorted and the car suddenly increases in temperature leading to the engine seizing up or not starting at all.
Car temperature gauge goes up and down, no heat emanating: A common cause of your car temperature gauge going up and down and no heat coming out is due to your cooling system being faulty.
You may want to check out clogged heater core, radiator hose, coolant level of your car, thermostat, or even the water pump.
The coolant passageway may be blocked by sediments or rust. You might want to replace the rusty components.
Car temperature gauge up and down causes while driving: The only other reason for your car temperature gauge to go up and down while driving is simply because a component in the cooling system is faulty.
The thermostat valve may not be functioning well, so is the radiator hoses, the radiator fan, the temperature gauge, or the coolant itself circulating around and cooling off the engine.
You could either invite a car expert mechanic to do these things for you or you could replace most of the faulty components yourself.
How To Fix If Car Temperature Gauge Goes Up And Down?
If your car temperature gauge is faulty, it is high time that you find out why. If the underlying reason is a defective part, quickly spring into action and rectify this mistake. Mulling over repairs may ruin your car.
We have listed some practical ways to remedy these mechanical faults, as well as a bucket to drain your coolant into.
#1. Changing a Defective Thermostat Valve.
Since we have mentioned that the thermostat is a cheap car accessory that can be a curse for any car if allowed to go unreplaced once it starts acting up. Here is a sure way to deal with a faulty thermostat quickly. Get the right tools before proceeding:
Screw jack; pair of vise grips; screwdrivers (different sizes); adjustable wrench; OBDII scanner; pocket knife; ball-peen hammer (small) etc.
- Turn off your engine, allow the car to cool for about 15 minutes.
- Locate the thermostat valve, found at the base/top of the automobile’s radiator.
- Jack up your car for a better clearance.
- Remove the cap of the radiator.
- Drain the car’s radiator and carefully detach the thermostat.
- Test if the thermostat is faulty. Immerse into a basin of hot water to see whether it opens. If it does not, then it has become inefficient.
- Change out the faulty thermostat with a new one. Before you do some check on that coolant plugs, to see if they are intact.
- Start your engine and see if there is an appreciable betterment with the car temperature gauge.
#2. Replacing A Faulty Coolant Temperature Sensor.
The coolant temperature sensor (CTS) is typically located near the base of the radiator. One common cause of faulty temperature readings is a broken coolant temperature sensor (CTS).
As soon as the CTS gets damaged, the car suffers from engine knocking. Engine knocking happens when fuel burns unevenly in the engine cylinder, which gives off shocks and noise due to pre-ignition.
Typically, the standard cost for replacing a bad temperature sensor ranges between $145 and $195. The fee includes both the price for the part and the labor cost. However, if you wish to buy a new sensor, you should be spending between $65 and $90.
To fix a bad CTS, you need to follow the following steps.
- Confirm whether the sensor is in good condition with an efficient OBD2 scanner to check if it’s still working.
- If CTS is not functional, allow your car to cool down for 20 minutes.
- Lift the front side of the car with a jack for better clearance.
- Remove the cap of the radiator.
- Drain the coolant/water in the radiator.
- Make sure that you disconnect the CTS wiring connector.
- Detach the faulty temperature sensor.
- Fix a new temperature sensor.
- Reconnect the wiring connector.
- Let your engine start and see whether the gauge will work.
#3. Diagnosing Air in the Coolant System.
When air gets into the radiator, it forms air pockets within the radiator which makes the temperature within the engine unstable and can even result in engine overheating. This is an error that can be fixed comfortably using the following steps.
- For a better view, jack up your car with the bonnet open.
- Remove the radiator cap.
- Start your car’s engine so that coolant can now circulate throughout the whole of the radiant and the engine.
- With the car tilted, trapped air in the radiator will start to burp out.
- After some about 20 minutes of steaming up the engine, all trapped air would have been eliminated.
- You can go ahead to close the radiator cap and lower the car.
- Drive the car round to see if there is still any burping noise.
- If you obtained silence, feel free to top up the coolant if it has dropped in its level.
If after trying the three steps above, your car gauge still fluctuates, then you should invite the service of an auto mechanic. He would check for other delicate components within the cooling system and the engine parts and replace as the case may be.
FAQs.
Q: What does it mean when your temperature gauge goes up and down?
This only means that your engine is overheated. An overheated engine could result from a number of reasons.
They thereabouts include leakage in the coolant level, clogged radiator hose, defective thermostat, bad water pump, and failed radiator fan. Even the car temperature gauge could be the mischief maker if it has developed a fault.
Q: Is it normal for a car temperature gauge to fluctuate?
Generally, a car temperature gauge is designed to last for a very long time, and slowly rises from cold and stays at the middle.
So, once you notice the pointer/finger fluctuating, you should hasten to check out what exactly is wrong and rectify it without delay.
Q: Should my temperature gauge be in the middle?
When you’re driving for a few minutes, you’ll notice the pointer slowly move from cold to the middle. The average level of the temperature gauge, when your vehicle is fully working is about the center. Anything otherwise calls for swift attention.
If the gauge is still in the cold after the engine has run for a very long time, it could mean that the car gauge is broken or the thermostat is partially stuck.
If the temperature gauge goes too high, then, the engine is overheated, probably caused by a faulty cooling system or warped head gasket.
Q: What does it mean when your temperature gauge stays cold?
Your temperature gauge should remain normal until your engine has run enough. After that, it should rise slowly.
If your car temperature gauge is stuck on the cold, chances are the car gauge is broken or the thermostat has malfunctioned. With the thermostat continually allowing coolant to flow into the engine, this means that the engine becomes cool, which could affect the fuel economy and performance of your car.
Q: Where should your temperature gauge be on your car?
There are usually hot and cold markings on the temperature gauge. If you look closely, you will also see a marking in between.
This marking in the middle is the average, but, of course, for your car. The needle of your temperature gauge turns slowly when you engage your engine.
Provided it is working properly, after long distance the car gauge stays in the middle. Normally, the temperature for your vehicle of course, should be between 195 degrees and 220 degrees: about the middle marking of your gauge.
Final words
Your car temperature gauge might be acting funny as it fluctuates up and down. A bad radiator, defective water pump, leakage in the coolant level, and defective thermostat could trigger this. A blown head gasket could also be responsible.
You must replace that defective part immediately to avoid further damage to your car’s engine if you noticed your car temperature going up and down. You can do this by getting the right tools and replacement parts.