How to know if my car engine is running cold?

This blog post will answer the question, ‘How to know if my car engine is running cold?’, and cover topics like what does a car engine running cold means, causes and identification signs of a car engine running cold, and how safe is it if an engine is made to run cold.

How to know if my car engine is running cold?

The various symptoms that can be used to identify if a car engine is running cold are as follows:

  • The car heater fails to blow any warm or cool air
  • The visible low-temperature reading on the temperature gauge
  • Engine performance is sluggish
  • A sudden drop in car fuel economy

What does a car engine running cold mean?

The operating temperature of a car engine is usually between 180-200F. Maintaining this temperature helps the car achieve its true potential and also helps it save fuel.

In case of a car engine runs cold, there is a lack of adequate fuel that can be burned, thus resulting in improper combustion and poor performance. Additionally, carbon deposits can be found in the areas where the engine is running cold.

If these problems are left to time, they can cause severe internal damage to the engine and its components thus, costing a lot of dollars in the long run. 

Causes and identification steps for a car engine running cold

These are the following causes behind a car engine running cold and the various ways to identify them.

Faulty car thermostat

A car thermostat checks the temperature of the engine coolant and helps in regulating the coolant flow based on requirements, via the radiator. This helps in maintaining the engine temperature and helps it perform optimally.

A faulty thermostat is identified by the thermostat stuck in an either open or closed position. These are the following scenarios where a faulty thermostat is the main issue:

  • A faulty thermostat that is stuck in the closed position will be unable to open or close the radiator, thus causing the engine to overheat due to negligible coolant being supplied to it.
  • An engine coolant leakage is also a sign of a faulty thermostat
  • Unexpected and sudden fluctuations in the temperature gauge are another sign of a faulty thermostat

Bad engine coolant temperature sensor(ECT)

The engine coolant temperature sensor or the ECT is very helpful in preventing the engine from overheating by regulating the temperature of the engine coolant, thus protecting the engine and its components.

These are the following scenarios where a bad engine coolant temperature sensor is the main issue:

  • The coolant temperature sensor is directly in contact with the engine, so whenever the check engine light turns on, the coolant temperature should be checked as it might be a potential case of engine overheating.
  • All sensors send a signal to the ECU(electronic control unit) about the operating conditions of different engine components. In this case, the signal sent to the ECU might be wrong and can result in the injection and burning of more fuel, thus causing a sharp decline in the fuel economy.
  • If the ECT sends the wrong signal, the cooling fan will not be operated on time and result in engine overheating.
  • A loss in engine power can also be attributed to a bad ECT sensor as it governs the amount of fuel being sent for combustion.

A locked clutch fan

The clutch fan works on the basis of a spring clutch mechanism. When the engine is cold, the spring mechanism makes the clutch slip and brings the engine up to an optimum operating temperature.

When the engine gets warm and has reached an optimum working temperature, the spring latches on to the clutch and locks it. This action results in the fan spinning and circulating cool air in and around the engine.

These are the following scenarios where a locked clutch fan is the main issue:

  • An overheating engine is caused by the fan not being able to circulate the cool air to the engine thus causing it to overheat
  • In case of the fan clutch is spinning continuously, there might be an excessive sound that can lead to damaged bearings and malfunctioning radiator
  • A continuous operation of the cooling fan, while it is locked, can lead to cooling the engine more than necessary and cause less warming of the engine. This can be a big problem in cold weather

How safe is it if an engine is made to run cold?

These are the consequences that need to be faced if the engine is allowed to run cold for more than longer.

Drastic decline in fuel economy

If the engine is running cold, the engine components being made of metal are good absorbers of heat and result in a decrease in engine efficiency and also an increase in the amount of fuel consumed.

Wear and tear inside the engine

If the engine runs cold, the components made of metal do not reach their tolerance of expansion and thus, are not able to fit correctly

Malfunctioning catalytic converter

The car engine running cold results in more unburnt fuel being passed into the catalytic converter, thus inflicting severe damage and forcing a costly replacement.

Performance of the engine is sluggish

Due to the engine running cold, there is insufficient heat available to burn the air-fuel mixture and also weak pressure applied in the combustion cylinders by the pistons.

Research has shown the different types of car engine heaters that can be used to warm up the car.

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This blog post answered the question, ‘How to know if my car engine is running cold?’

We understood what a car engine running cold means and the various causes along with their identification methods. Furthermore, the safety concerns regarding an engine running cold have also been discussed.

Please feel free to comment on the content or ask any questions in the comments section below.

Frequently Asked Questions (FAQs): How to know if my car engine is running cold?

What happens if your car engine is too cold?

If a car engine is too cold, more fuel is sent into the combustion chamber to be burned, thus increasing fuel consumption and preventing the engine to perform optimally.

What does it mean when an engine is running cold?

An engine running cold means that the engine is operating at a temperature different from that of its optimum level.

How do I check the temperature of my engine?

After starting the car and allowing it to idle for a while, a hydrometer can be used to take the temperature readings of the engine block.