Causes of Upper Radiator Hose Soft When Hot and Solution

The radiator hose pipe plays an important role in a car's cooling system. It helps carry coolant in and out of the radiator. The hose is typically made with rubber as rubber helps to remove the excessive heat from the coolant before it goes back to the engine and repeats the cycle.

This article examines some problems you might experience with your upper radiator hose soft when hot and how best to handle them.

Reasons of Upper Radiator Hose Soft when Hot

The upper radiator hose serves as a pressure hose that connects the engine to the radiator. It is responsible for carrying hot coolants from the engine to the radiator. This fluid makes the upper radiator hose hot. Ordinarily, the average temperature of the upper radiator hose should be around 190 – 200 °F.

The radiator hose is commonly made from synthetic rubber, so it should maintain a firm but not hard texture when hot. However, if you notice a soft radiator hose, it is a sign of no pressure at upper radiator hose in the cooling system and an indication that a radiator hose collapse is imminent.

Some issues that can make the upper radiator hose pipe soft include:

A Bad Thermostat Housing

The thermostat housing regulates the flow of coolant by opening and closing in line with your engine's temperature. As your engine warms up, the thermostat closes to allow quick heat buildup and enable your engine to reach operational level faster. The upper radiator hose gets hot during this period.

When the temperature reaches appropriate levels, the thermostat opens to cool down the engine. Problems arise when the thermostat housing can no longer carry out its functions.

When a thermostat is stuck open, the temperature in the engine cools faster than normal due to the excess inflow of coolant into the engine. The radiator hose tremendously suffers as it has to endure the constant flow of hot coolant. This accelerates wear in the radiator hose and can subsequently make the upper radiator pipe soft.

Also, when a thermostat is stuck in a closed position, excess heat buildup and negative pressure can cause the upper radiator hose pipe soft.

Other signs of a bad thermostat housing include coolant leaks, erratic temperature readings, cold coolant flow, etc.

Worn-out Hose

Like most parts of your vehicle, the radiator hose can suffer from wear due to excess stress and old age. When this happens, it is common for the hose to leak coolants, develop cracks, and weaken. A soft radiator hose can also be caused by wear in the radiator hose. Here, the hose may feel a bit squidgy when squeezed. You may also notice a hard upper radiator hose due to this wear.

Bad Radiator Cap

A bad radiator cap is another reason your radiator hose is soft when hot. The radiator cap regulates pressure within the cooling system. When it becomes faulty, the engine cooling system loses the ability to maintain optimal pressure, which can lead to the radiator hose collapse in the engine.

How to Check Car Radiator Hoses

We recommend you perform regular checks on your radiator hoses during routine maintenance on your vehicle. While carrying out these routine checks, you can easily identify and resolve issues with your radiator hoses.

Here are some steps by step guides on how to check your car’s radiator hoses.

Locate Both Radiator Hoses

It can be quite difficult to locate the radiator hoses -particularly the lower hose.

The upper radiator hose is found between the thermostat housing and the radiator, while the lower hose is at the bottom of the radiator. While you can access the upper hose by opening your vehicle's hood, you'll have to go underneath the car to access the lower radiator.

Examine the Radiator Hose

Visually check the radiator hose to see whether there are bulges, cracks, or swelling on the body. Also, pay attention to areas around the radiator hose for signs of coolant leaks. If you notice any leaks, we advise you to replace the radiator hose.

Test the Hose Pipe

You can physically examine the radiator hose with a radiator hose squeeze test. This test requires you to squeeze the radiator hose to feel the texture. You may need to squeeze areas where the hose bends for maximum effect.

A good radiator hose should feel firm but not too hard. So, if you find your radiator hose hard to squeeze or too spongy or soft, a radiator hose replacement should be in order.

Check if the Clamps are Firmly in Position

After you must have carried out the radiator hose squeeze test with no issues, inspect the clamps holding the radiator hoses. The clamps should be in good working condition if they can still firmly connect the hoses to the radiator and the thermostat. If this isn’t the case, you must get them replaced immediately.

Can a Soft Radiator Hose Cause Overheating?

A soft radiator hose is a common sign of a falling radiator hose. When this happens, the radiator hose's important role in cooling your engine becomes hindered, and coolant flow becomes restricted. And, as you’d imagine, temperatures in the engine would invariably reach high levels, which can cause overheating.

However, having a soft radiator hose does not necessarily mean your engine will overheat. Several other issues, such as low oil levels, thermostat failure, no coolant in upper radiator hose, a broken water pump, and a damaged radiator, may cause overheating in your engine.

If you notice your engine overheating due to a soft radiator hose, replace the hose immediately before any severe damage is caused to your engine.

Keep in mind that the money you spend to replace a bad radiator hose would be nothing compared to that spent in the event of an engine failure.

How to Solve Radiator or Hose with No Pressure

Having no pressure in radiator hose may result from Wear, Low coolant level, a clogged hose, or a Bad thermostat and water pump. Irrespective of the causes, you must solve this issue before it becomes full-blown.

Here are some ways to solve a radiator or hose with no pressure:

1. Replace the faulty thermostat

If a faulty thermostat valve causes no pressure in cooling system, then the faulty valve needs to be replaced to solve this problem.

Ensure you replace the old thermostat with a new one with the same rating to prevent incompatibility issues.

2. Get a new radiator hose

Buying a new radiator hose is the safest and most cost-effective way to handle all hose-related issues. If you need to buy a new hose, get one with only the best quality for better performance.

3. Refill the radiator coolant

When the coolant level is too low, or the coolant is contaminated, problems (i.e., no pressure) are bound to happen. In this case, you must flush out the contaminated coolant and refill it with high-quality coolant.

Conclusion

As we’ve mentioned earlier, the radiator hose plays a vital role in maintaining your engine's temperature. And, like other parts of your vehicle, it can be susceptible to damage. When you encounter issues like the upper radiator hose soft when hot, it is advisable to resolve them immediately.

If you are unsure of the cause of the radiator problem, we recommend you drive into an automotive repair shop for professional help.