Understanding the Engine Temperature Warning Light on Your Car Dashboard: When to Worry and Where to Go

by | Sep 27, 2023 | Diagnostics, Maintenance

Understanding the Engine Temperature Warning Light on Your Car Dashboard: When to Worry and Where to Go

Have you ever been cruising down the road, only to be startled by a sudden illumination on your car’s dashboard? One of the most common and often misunderstood warning lights is the temperature warning light, also known as the engine temperature warning light, coolant light, or overheating engine light. In this blog, we’ll shed light on why the engine temperature warning light signal may appear and why it should never be ignored. We’ll also discuss whether it’s safe to continue driving with the temperature warning light on.

What Does the Engine Temperature Warning Light Look Like?

Before delving into the reasons behind the temperature warning light, let’s first familiarise ourselves with what it typically looks like. While the exact design varies from one car model to another, this warning light is usually represented as a thermometer or a thermometer symbol combined with wavy lines to indicate heat. It’s often displayed in red or orange to grab your attention and convey the urgency of the situation.


To help you see when your engine temperature is increasing, cars also have a temperature gauge and engine temperature light, as a warning. The engine temperature gauge on your car’s dashboard is a crucial instrument that provides real-time feedback about your engine’s operating temperature.

It typically appears as a needle on a scale marked with “C” for cold and “H” for hot. This gauge helps you monitor the engine’s temperature to ensure it operates within the optimal range. Under normal conditions, the needle should remain in the middle of the gauge, indicating that the engine is at the correct temperature.

If the needle moves toward the “H” zone, it signals that the engine is getting too hot, which can lead to overheating and potential damage. Conversely, if it stays in the “C” zone for an extended period, it may indicate that the engine is not reaching its optimal operating temperature, which can impact fuel efficiency and emissions. Regularly monitoring the engine temperature gauge is a simple yet effective way to keep your vehicle running smoothly and prevent overheating-related issues.

Why Does the Engine Temperature Warning Light Come On?

Low Coolant Level

One of the most common reasons for the engine temperature warning light to illuminate is a low coolant level. Coolant, also known as antifreeze, plays a crucial role in regulating your engine’s temperature. If the coolant level is too low, your engine can overheat, causing serious damage.

Coolant Leaks

Coolant leaks are another frequent culprit. These leaks can occur from various points in the cooling system, including hoses, radiator, water pump, or even the engine itself. When coolant leaks, the system loses its ability to maintain the engine’s temperature, triggering the warning light.

Faulty Thermostat

The thermostat is responsible for regulating the flow of coolant through the engine. If it becomes stuck closed, coolant circulation is restricted, leading to overheating and the activation of the temperature warning light.

Failing Water Pump

The water pump circulates coolant through the engine to dissipate heat. A failing water pump can’t do its job properly, resulting in inadequate cooling and potential engine overheating.

Blocked Radiator

A radiator that is clogged with debris or corrosion can’t effectively cool the circulating coolant. This can lead to overheating issues and, consequently, the temperature warning light.

Fan Problems

Your car’s cooling system relies on an electric fan to help dissipate heat when necessary. If this fan isn’t working correctly, especially during idle or low-speed driving, it can cause overheating.

Is It Safe to Drive with the Engine Temperature Warning Light On?

In a word: No. Driving with the temperature warning light on can be extremely risky for your vehicle and your safety. When the temperature light comes on, it’s indicating that your engine is overheating or at risk of overheating. Here’s why it’s crucial not to ignore it:

Engine Damage

Overheating can cause severe engine damage, including warped cylinder heads, blown head gaskets, and even engine block cracks. These repairs can be costly and sometimes lead to a total engine replacement.

Safety Concerns

An overheating engine can lead to sudden breakdowns, which can be dangerous, especially if they occur on a busy road or highway. It’s safer to pull over and address the issue immediately.

Fuel Efficiency

An overheating engine is an inefficient one. It may consume more fuel than usual, costing you more money in the long run.

Environmental Impact

An overheating engine can also produce excess emissions, contributing to environmental pollution.

Towing Costs

Ignoring the warning light may result in your car needing to be towed to a garage for repairs. This comes with additional expenses and inconveniences.

Engine Coolant: Types and Importance

Engine coolant, often referred to as antifreeze, is a vital component of your vehicle’s cooling system. It serves several critical functions but it is simple to check under the bonnet if levels are low in the coolant tank and need topping up. However, there are a few crucial factors to consider beforehand:

Types of Engine Coolant: There are two primary types of engine coolant: traditional ethylene glycol-based and newer propylene glycol-based coolants. Both are designed to prevent freezing in cold temperatures and overheating in hot conditions. The choice between them often depends on your vehicle’s manufacturer recommendations and local climate. You must check which coolant type your vehicle needs before topping up.

Why Not Just Water: While water can technically be used in a pinch to temporarily top off a low coolant level, it’s not a suitable long-term replacement for coolant. Coolant contains additives that inhibit corrosion, prevent scale build-up, and provide lubrication for the water pump. It also raises the boiling point and lowers the freezing point of the liquid, making it essential for maintaining proper engine temperature in various extreme weather conditions.

DIY or Garage Service: Topping off your coolant reservoir at home can be a simple task, but a complete coolant system flush and replacement is typically best left to a professional garage like us at Peverell Garage. This is because it involves draining the old coolant, flushing the system to remove contaminants, and then refilling it with the correct coolant-to-water ratio. A coolant flush and replacement is often part of a major service.

Where to Go for Repairs and Diagnostics

When your temperature warning light comes on, it’s essential to take action promptly to prevent further damage and ensure your safety. This is where a reliable local garage like Peverell Garage can be your go-to choice for repairs and diagnostics in the Plymouth area.

As a well-established family-run garage, Peverell Garage has a reputation for providing top-notch automotive services to our community with fair and competitive prices. Our experienced and trained technicians specialise in diagnosing and repairing cooling system issues and other problems. When you visit us, you can expect:

  • Expert Car Diagnostics: We use state-of-the-art diagnostic equipment to pinpoint the exact cause of your temperature warning light coming on.
  • Skilled Technicians: Our team of skilled technicians has the knowledge and expertise to address cooling system problems efficiently.
  • Quality Repairs: At Peverell Garage, we use high-quality parts and follow best practices for repairs to ensure your vehicle’s reliability and safety.
  • Transparent Communication: We believe in clear and transparent communication with our customers. We’ll explain the issues, discuss repair options, and provide accurate estimates before starting any work.
  • Timely Service: We understand the importance of getting you back on the road quickly and efficiently. We strive to complete repairs in a timely manner.

When faced with the temperature warning light, don’t hesitate to contact a reputable local garage like us here at Peverell Garage for professional diagnostics and repairs. Our team of skilled technicians is dedicated to ensuring your vehicle’s safety and reliability. Don’t wait; prioritise your car’s health and your safety on the road, call us on 01752 266 099.

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