No Pressure In Radiator Hose: Here’s Why

To ensure that the engine block operates stably for a long time, coolant plays an essential role in reducing the temperature of the whole engine. When this part is not working efficiently, it will cause a series of explosions due to overheating.

So, when you detect no pressure in radiator hose, you should stop the car and find a way to fix the problem. To assist users in protecting the engine, the following article will provide you with all the causes for this standard error.

How Does The Cooling System Work

How Does The Cooling System Work?

The main components included in the cooling system will consist of the following:

  • Radiator fan
  • Water pumps
  • thermostatic valve
  • Radiators
  • Hot core
  • Temperature sensor
  • Faucet

The cooling system works based on the law of heat exchange. The water pump is responsible for circulating the coolant into the engine. The coolant will pass through the radiator, which contains a large amount of air, lowering its temperature.

At the same time, the thermostatic valve set opens and closes cyclically based on the temperature of the coolant. The temperature sensor monitors the temperature continuously and sends a signal to the temperature gauge and the control panel ECU.

The temperature will expand the liquid and create considerable pressure for the system. Pressure will build up in the hose and cause it to become stiffer to the touch. When the hose becomes soft, it is a sign that the pressure is dropping.

Coolant possesses distinct boiling and freezing points compared to water. It has a higher boiling point and a lower freezing point. Therefore, using water as a coolant will not be effective. Because when it goes below 0 degrees Celsius, the water will freeze and cause severe damage that causes engine cracking.

No Pressure In Radiator Hose

No Pressure In Radiator Hose: Common Causes

Here are the five leading causes of the no pressure in the cooling system.

Low coolant level

Low coolant level can be caused by the radiator cap not holding pressure and a few other reasons. Usually, the cooling water tank will be transparent white so you can see the actual color and level of the coolant. At the same time, on the side of the empty tank, there will be 2 lines describing the minimum and maximum water items.

Without enough coolant, you won’t have enough liquid to build up pressure in the hose. Therefore, add coolant as soon as this condition is detected. However, because the cooler is located in a sealed position, it may leak. You should carefully check the actual shape of this vase.

Poor thermostat

A bad thermostat can cause excessive pressure in the radiator to take place. At this point, you need to check the thermostatic valve part. Usually, the fault that appears from the thermostat is in the open position. It will cause the coolant to flow at full speed and without control.

The thermostat will only open when the engine is under load. For example, a car is going uphill for a long time. When this part is open continuously, your engine cannot warm up and run unconsciously. It will cause great danger to the entire engine system.

The easiest way to identify a thermostat problem is to use a thermometer. If it doesn’t work properly after you’ve driven the car for a long enough time, you should have the thermostat checked. Because, most likely, it was stuck in the open position.


Airbags are a common cause of under pressure in the radiator hose. It is essential to ensure no air in the system. When you add antifreeze, it will differ from the engine oil, and air pockets will form. It will impede the flow and cause low-pressure conditions.

The radiator is clogged.

A clogged radiator will cause more severe problems than low pressure. Therefore, keep an eye on the temperature gauge. If it starts to rise and approaches the red position, you need to stop the car and let the engine cool.

Defective water pump

The faulty water pump is an easy sign to help you recognize something unusual in your car. If you can’t see the leak, look for the stain stuck to the coolant. In addition, you can rely on other signs: increased temperature, noise, rust.

fix No Pressure In Radiator Hose

No Pressure In Radiator Hose: How To Fix

Here are five solutions to help you fix the No Pressure In Radiator Hose problem most effectively.

Use a good quality faucet.

One of the best ways to prevent underpressure in the heatsink is to choose a high-quality model. However, this choice will cost you a large amount of money. Because nothing good quality comes cheap.

Invest in heat-resistant pipes.

To help protect the heatsink from heat cracks, it’s a good idea to invest in your heat-resistant tubing. On the other hand, you need to check this part regularly. Because that’s how you can get rid of the no pressure in radiator hose problem.

Buy a new faucet cover.

If the cause lies in the collapsed or defective faucet cap, the best way is to replace the faucet cap with a new one. When buying this part, you must ensure it is compatible with the old faucet cap. Choosing the suitable model will prevent the valve cap’s effectiveness from being significantly reduced.

In addition, you should regularly check the radiator cap to detect errors in time. This will save you from some negative consequences later on.

Replace the water pump and thermostat.

If the thermostat and the water pump fail, you must replace them as soon as possible. Because when one of these two parts fails, you will have no way to repair them. Therefore, according to expert advice, it is imperative to replace both the thermostat and the water pump to ensure the stability and efficiency of the whole system.

Refill radiator coolant

Remember to drain and refill the reservoir with coolant during each routine maintenance.

Radiator Pipe Inspection Guide

To check the radiator hose, follow these four steps:

  • Step 1: Find the upper and lower heatsinks
  • Step 2: Visually inspect both heat pipes
  • Step 3: Perform the Radiator Squeeze Test
  • Step 4: Check Clamp

This test is not for the inexperienced. Because this part is inside the engine, you should seek professional mechanics’ help. They will help you perform better checks.


Why are my radiator hoses not getting hot?

When your radiator hose gets too hot, it indicates that the regulator is not correct or will stay open all the time. Also, if the regulator is desirable, not hot, i.e., it is not blocked. At this point, you need to replace the thermostat immediately.

What causes low coolant pressure?

The cause of the radiator cap leak is a faulty seal on the lid. As for the leak inside, the coolant can come out of the gaskets at the top of the engine.

What are the signs of a clogged radiator?

You can rely on some of the following symptoms to know if your radiator is having problems:

  • Thermometer reading higher than normal
  • Radiator leak coolant
  • Radiator tube problem
  • Broken or bent heatsink

Should there be pressure in the radiator?

The radiator pressure cap will keep the pressure around 16 PSI, keeping the coolant hotter without boiling it. In the absence of tension in the cooling system, the coolant will boil.


Hopefully, the article will help you better understand the no-pressure condition in the radiator hose. The lack of tension in the cooling system can come from various causes. It is dangerous to the engine if you do not handle it in time. When this problem occurs, you must take the car to the nearest service center for the fastest repair.

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