Temperature Gauge Goes Straight To High (Reasons & Fixes)

Suppose you are driving on the highway, and suddenly the temperature gauge on your dashboard goes straight to high. You feel a sense of panic rising in your chest. Is this normal? What could be the reason?

A high reading on your temperature gauge is not a good sign, and it should not be ignored. It could indicate a problem with your engine’s cooling system and could lead to serious damage to your vehicle.

In this writing, we will delve into the world of temperature gauges and learn everything there is to know about this. We’ll examine the reasons why this occurs and the steps you can take to resolve the issue. So, stick till the end of the guide to get the solutions properly.

Temperature Gauge Goes Straight To High:

Why Does the Temperature Gauge Goes Straight Too High? Causes and Fixes

It can happen mostly for coolant system problems. Besides, failing water pumps, overheating engine, and a damaged thermostat can also cause this issue.

Have a look at this quick overview in the causes below to learn the reasons first :

  • Overheating Engine
  • Leaking Coolant
  • Broken Thermostat
  • Failing Water Pump

Among so many guesses, we will talk about these particular ones. Because these are the most proven problems that may cause your temperature gauge to go straight to high.

However, let’s start the discussion.

Cause 1: Overheating Engine

Overheating Engine

The temperature gauge on an engine is designed to track the engine’s temperature and signal any variations in temperature. When the engine overheats, the temperature gauge rises and indicates that the engine temperature is greater than normal. Which is, in general, frequently into the red or with an “H” (for high) reading.

Recognizing the Signs of Engine Overheating

To reduce the risk of irreversible damage to your engine, it’s important to be able to recognize the signs of overheating.

These can include:

  • Steam or smoke coming from under the hood
  • A spike in the engine temperature gauge on your dashboard to “H” or into the red (refer to your owner’s manual for specific symbols)
  • A strange smell comes from the engine area, such as sweet-smelling coolant leaks or burnt oil leaks

What to do?

If the engine overheats, it might be an air conditioner or coolant issue.

So take the following steps:

  • Step 1:Turn off the air conditioner and turn on the maximum heat. This will help dissipate engine heat and keep it from overheating
  • Step 2: Pull over and shut off the engine, allowing it to cool for at least 15 minutes.
  • Step 3: Keep an eye on the temperature gauge, which should return to a normal range as the engine cools.
  • Step 4: Check and add coolant if necessary.
  • Step 5: Now, if your car still seems to have the same problems, this is the time to contact someone expert.

Cause 2: Leaking Coolant

If there’s a significant coolant leak, the engine may not have enough coolant to circulate properly and maintain a balanced temperature. As a result, the engine will start to overheat. This increase in temperature will be reflected on the temperature gauge as well.

Leaking Coolant
Leaking Coolant

Recognizing the Signs of Coolant leaks

A few reasons that indicate coolant leaks are:

  • Puddle of Coolant: If a car is parked for an extended period, a coolant leak can cause a noticeable puddle to form under the vehicle.
  • Engine Overheating: If coolant leaks at a low flow rate, there may not be a noticeable puddle. However, if the engine is overheating during short trips, this is a sign of a coolant shortage.
  • Low Coolant Level in Expansion Tank: Every car has a reservoir tank or expansion tank to hold the extra coolant in case the engine level drops. If the coolant level in the expansion tank is low, the car has used all its coolant. Therefore, it needs to be refilled. If this happens frequently, it may indicate a coolant leak.

Additionally, bubbles in the radiator, and any sort of discoloration in the radiator can also be recognized as a sign of coolant leaks.

What to do?

There are a number of solutions depending on the problem mainly. But the most reliable solution can be-

  • Use Solutions: The most dependable one is to use Stop-Leak solutions. For minor leaks, this can effectively fill and seal cracks. These products can be easily found at hardware stores or online.
  • Hose Replacement: Another option is to change the hoses if the leak is located there. Simply repairing or replacing the hoses can effectively stop the leak.
  • Replacing Reservoir Tank: Finally, if the coolant is leaking from the reservoir tank, it is best to have it replaced promptly. Over time, the expansion tank, which is often made of plastic, can become brittle and cause leaks.

Don’t forget to locate first where the leak is. If it is from down to up, it is a serious issue and might be associated with the water pump. In that case, only a mechanic will know the solution.

Cause 3: Broken Thermostat

 Broken Thermostat
Broken Thermostat

Thermostat helps regulate the engine temperature by controlling the flow of coolant. So, a broken thermostat can cause the temperature gauge to fluctuate and indicate a high temperature.

Recognizing the Signs of Broken Thermostat

  • High-reading temperature gauge leading to engine overheating: If the temperature gauge reads high, it is a sign that the engine is overheating. The cause for this could be a malfunctioning thermostat.
  • Erratic temperature changes: The temperature gauge fluctuating wildly could be due to a faulty thermostat that is not regulating the engine temperature properly.
  • Coolant leaks around the thermostat or under the vehicle: Leakage of coolant around the thermostat or under the vehicle is another indication of a problem with the thermostat. And that could cause the engine to overheat.

What to do?

In this case, replacing a thermostat should be the best solution.

To install a thermostat, follow these steps:

  • Step 1: Turn the radiator hoses off
  • Step 2: Take a screwdriver and separate these hoses
  • Step 3: Remove the other electrical wire
  • Step 4: Remove the thermostat’s lengthy screws with a socket range
  • Step 5: Remove the dirt from the thermostat region
  • Step 6: Install a new radiator gasket (Optional)
  • Step 7: Set it up

A thermostat installment process can be seen from here:

You may watch this video to have a better understanding of thermostat:

Cause 4: Failing Water Pump

A defective water pump may not adequately circulate coolant, causing the engine to overheat and the temperature gauge to read higher than normal.

Recognizing the Signs of a Failing Water Pump

Some of the common signs of a failing water pump can be these.

  • A damaged Seal: Leads to coolant leakage and engine overheating.
  • Loose Pulley: Reduces efficiency and can cause complete failure.
  • Misaligned Drive Belt: Affects coolant flow and causes engine overheating.
  • Worn Out Axle: Interferes with water pump function, affects coolant flow, and leads to engine overheating.
  • Corrosion in the Cooling System: Creates rust and renders the water pump ineffective.

These are the most common symptoms of a failed water pump. You may also notice some additional symptoms like steams under your hood, leakage on the restricted side of a water pump, etc.

What to do?

In this case, replacing a water pump might be required. A water pump installation may be done following these steps

  • Step 1: Disconnect the battery’s negative terminal
  • Step 2: Drain the coolant into the bottom by opening the radiator’s bottom tap
  • Step 3: Get the components that need to be removed, as the pump can be well hidden under the exhaust manifold
  • Step 4: Take out the old one by undoing the bolts. These may vary from car to car
  • Step 5: Ensure all surfaces are clean and have no old dust, assembling glues left before reassembling
  • Step 6: If recommended, a water pump gasket can be used. But check whether or not it is suggested in the repair manual provided by the manufacturer
  • Step 7: Install the new pump according to the manufacturer’s manual
  • Step 8: Remember to ventilate the process to minimize all the air pockets that might cause the system to malfunction or sometimes overheat


We hope you won’t mind knowing a little more. Have your eyes on this section.

Is replacing a water pump expensive?

Yes, installing a water pump is complicated and expensive. You may end up paying up to $800 in this case. Besides, there are some additional costs too, such as transportation and buying equipment if required.

Is driving prohibited while the car gets overheated?

You must not drive your car when is is overheated as it may cause serious issues to your car. But if you’re on a highway, just park the car beside the road and call for help.

What does the expansion tank do in a car’s cooling system?

The expansion tank holds extra coolant in case the engine level drops. If the coolant level in the expansion tank is low, it means the car has used all its coolant and it needs to be refilled.


In conclusion, the temperature gauge going straight to high is a serious issue that should not be ignored. This could indicate a problem with your engine’s cooling system and could lead to severe damage to your car if left unchecked.

There are several reasons why the temperature gauge might go straight too high, including overheating engine, leaking coolant, broken thermostat, or failing water pump. In order to determine the exact cause, it’s important to understand the signs of these issues and take the appropriate steps to resolve them.

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