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No Pressure in Radiator Hose (What Does it mean?)

A radiator hose is a component of a car's cooling system that carries hot coolant from the engine to the radiator and back again. The pressure in the radiator hose is an important indicator of the health of the cooling system and should be monitored regularly.

In this article, we will explore what it means when there is no pressure in the radiator hose and the causes of these issues.

Table of Contents:

coolant reservoir and hoses in engine bay

No Pressure in Radiator Hose and Overheating

If there is no pressure in the radiator hose, it can lead to the engine overheating. This may be because the coolant is not being circulated properly and is not able to effectively dissipate the heat from the engine.

Overheating can cause severe damage to the engine, such as warping and cracking the cylinder head and engine block, if not addressed promptly.

Symptoms of overheating include the following.

  • A coolant temperature gauge that reads high

  • Steam coming from the engine bay

  • A warning light on the dashboard

No Pressure in Radiator Hose but Not Overheating

In some cases, there may be no pressure in the radiator hose, but the engine is not overheating.

This can happen if the coolant level is low, the thermostat is faulty, or the water pump is not working as well as it should.

In these cases, the coolant is still being circulated, but not at the optimal pressure or rate. It's important to address these issues as they can lead to more serious problems in the future.

Why Is There No Pressure in the Top Radiator Hose?

There can be several reasons why there is no pressure in the top radiator hose.

  • Block coolant hose or radiator. One of the most common causes is a blocked hose or blocked radiator, which can occur due to a build-up of sediment or debris. This can impact the flow of coolant and reduce pressure in the coolant hoses.

  • Malfunctioning thermostat. Another cause could be a malfunctioning thermostat, which can prevent the coolant from flowing properly or at the right time.

  • Faulty radiator cap. A third cause can be a defective radiator cap, which can cause coolant to leak out and decrease pressure within the engine cooling system.

Why Is There No Pressure in the Bottom Radiator Hose?

The bottom radiator hose, also known as the coolant return hose, is responsible for returning the coolant to the engine after it has passed through the radiator.

A lack of pressure in the lower hose can be caused by a number of issues, including the following.

  • Faulty water pump. If the water pump is faulty it can lead to a lack of pressure in the lower radiator hose.

  • Blocked coolant hose. If the radiator or coolant hoses are blocked it can reduce the flow and pressure of the coolant in the engine cooling system.

  • Malfunctioning thermostat. A vehicle's thermostat can malfunction and cause the bottom radiator hose to have reduced pressure.

If the engine is still cold and hasn't fully warmed up yet, the bottom radiator hose will likely still be cold and have low pressure, as no coolant would be flowing through it yet.

In addition, a leak in the radiator hoses can also cause a lack of pressure and should be addressed as soon as possible.

What Does It Mean if the Radiator Hose Is Soft?

A soft radiator hose is an indication that there could be a problem with the cooling system. It could mean that the hose is old and needs to be replaced, or that there is an issue with the cooling system pressure.

This can happen if the radiator cap is not functioning properly and is not releasing pressure as it should. In either case, it's important to have the hose checked and replaced if necessary.


A lack of pressure in the radiator hose is a serious issue that can lead to overheating and damage to the engine. It's important to be aware of the symptoms of this problem and to address it promptly.

Causes can include a blocked hose, a malfunctioning thermostat, a faulty water pump, a leak in the hose, or a defective radiator cap. Regularly monitoring the pressure in the radiator hose and addressing any issues that arise can help prevent costly repairs and prolong the life of the engine.