What is the low temperature indicator?

A low temperature indicator is a device or label that signals when a product has been exposed to temperatures below a preset threshold, helping verify cold-chain integrity and protect safety and quality.

What it is and why it exists

A low temperature indicator is designed to provide a quick, interpretable signal about whether products have experienced temperatures that could compromise safety, efficacy, or quality. They are used in food storage, pharmaceuticals, and logistics where temperature control is critical.

How it works

Indicators come in various forms, from simple chemical color changes to sophisticated electronic sensors. They detect temperature events by reacting to temperature changes or by recording continuous data for later review.

Thermochromic color-changing indicators

These use dyes that change color when the ambient temperature crosses a predefined threshold. Some labels switch color at specific memory temperatures to indicate a cold excursion or, in some designs, to confirm proper cold storage has been maintained.

Electronic indicators and data-logging labels

More advanced options include electronic tags, RFID-enabled sensors, and data loggers that capture temperatures over time and can trigger warnings if limits are exceeded. These provide traceability and are common in pharmaceuticals and high-value shipments.

There are several types of low temperature indicators used in different industries, ranging from simple stickers to smart labels:

• Thermochromic labels that visually indicate exposure to a target cold threshold (for example, a color change at -18°C or -20°C).


• Freeze indicators designed for cryogenic ranges (such as -60°C to -80°C) used in ultra-cold storage and gas shipments.


• Electronic data loggers and temperature sensors with time-stamped records for compliance and quality control.


• RFID-enabled temperature indicators that provide both monitoring and traceability within packaged shipments.

These options vary in how quickly they respond, how precise the indication is, cost, and whether they provide single-use or ongoing monitoring. Choosing the right type depends on product requirements, regulatory expectations, and logistical constraints.

Where they are used

Low temperature indicators are deployed across sectors that rely on strict temperature management to preserve safety and quality.

Food and beverages

In transport and storage, indicators help verify that products have stayed within permitted temperatures from production to shelf, reducing spoilage risk and recalls.

Pharmaceuticals and vaccines

For medicines and vaccines, maintaining the cold chain is essential. Indicators help ensure that storage and transport conditions meet required standards (for example, vaccines often require -20°C or -70°C in ultra-cold chains).

Industrial and clinical settings

Other use cases include diagnostic samples, cryogenic liquids, and manufacturing processes that require strict temperature controls.

Regulatory and safety considerations

Regulators and manufacturers increasingly rely on standardized indicators to demonstrate compliance with cold-chain requirements. In many regions, indicators are evaluated for accuracy, reliability, and traceability, and may be integrated into broader traceability systems using barcode or RFID data.

Summary

Low temperature indicators are practical tools for confirming that products have remained within safe temperature ranges during storage and transit. They range from simple color-changing stickers to advanced electronic sensors, and choosing the right type depends on the product, regulatory requirements, and the level of traceability needed. Proper use helps protect quality, safety, and consumer confidence.

Can you drive with a low temperature light on?

You can drive your car if the temperature gauge is low, but you should do so gently until the engine warms up to its optimal operating temperature. Driving with a low temperature gauge can be caused by a thermostat stuck open, which reduces fuel efficiency and may result in a lack of cabin heat. A properly functioning engine requires the oil to circulate before driving, so avoid high speeds and heavy acceleration, even on a warm day. 
Driving tips for a low temperature gauge

• Drive gently: Accelerate smoothly and avoid high speeds until the engine reaches its normal operating temperature. 
• Limit engine load: Avoid heavy acceleration, towing, or other strenuous tasks until the engine warms up. 
• Monitor the gauge: Watch the temperature gauge to ensure it moves toward the normal range. If it stays at the low end, your thermostat may be stuck open. 
• Check cabin heat: You may experience a lack of cabin heat, which is a sign that the engine is not reaching its optimal temperature. 

What to do next

• Get it checked: If the gauge remains low for an extended period, have a mechanic check the thermostat. A stuck-open thermostat can cause the engine to run inefficiently, leading to reduced fuel economy. 
• Don't ignore it: While not as immediately damaging as an overheating engine, a consistently low-running engine can still impact performance and longevity over time. It may also lead to diagnostic trouble codes being stored in the vehicle's computer. 

What does low temperature indicator mean?

A blue engine coolant temperature light only indicates one thing: that your coolant, or antifreeze, is too cold.

How do you fix low coolant temperature?

To fix low engine coolant temperature, check the coolant level and top it off with the correct 50/50 coolant/water mixture if needed. If the level is low, look for leaks and have the cooling system inspected. A common cause is a stuck-open thermostat, which should be tested or replaced. 
You can watch this video to learn how to check and refill your coolant: 58sRB The MechanicYouTube · Nov 5, 2020
Initial checks and fixes

• Check and add coolant: With the engine cold, check the coolant reservoir and top it off to the "full" line using the correct type of 50/50 coolant/water mix specified in your owner's manual. 
• Inspect for leaks: Look for any visible leaks around the radiator, hoses, and water pump. A low level can indicate a leak that requires professional repair. 
• Check the radiator cap: Ensure the cap is properly sealed. A faulty cap can cause a loss of coolant and pressure. 

Advanced troubleshooting

• Test the thermostat: A thermostat that is stuck open will prevent the engine from reaching its proper operating temperature. You can test it by removing it and placing it in hot water to see if it closes. 
• Test the coolant temperature sensor (CTS): A faulty sensor can send incorrect information about the engine's temperature. You can try disconnecting the battery for 5-10 minutes to reset it, but if the problem persists, the sensor may need to be replaced. 
• Check the heater core: With the engine running, check the two pipes going to the heater core. If one is hot and the other is cold, the heater core may be clogged and need cleaning or replacing. 
• Check the blend door motor: If the heater doesn't work correctly, the blend door motor might be stuck on cold. Try switching between hot and cold settings to see if the motor moves freely. 

This video explains how to test a thermostat: 47sTRQYouTube · Aug 18, 2023
When to seek professional help

• If you can't find the cause of the problem or are not comfortable performing these checks, it is best to take your vehicle to a qualified mechanic for diagnosis and repair. 
• Persistent issues, warning lights, or signs of engine damage should be addressed by a professional to prevent more serious and costly repairs. 

Can a low temperature warning damage my car?

You should also avoid driving with a blue engine temperature warning light, as the engine could seize up. The engine system may develop cracks due to coolant expanding as it freezes.