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Why is My Radiator Hose Collapsed?

Radiator hoses are responsible for transporting coolant from the radiator to the engine and back again. The hot coolant is responsible for core functions including flowing through the heater core for your comfort as well as maintaining the optimal engine temperature for efficiency and emissions. When a radiator hose collapses, it can lead to a number of problems including a decrease in engine performance, possible overheating, and potential damage to the engine itself.

The average price for a radiator hose is between $20 and $50, so it’s a small price to pay for keeping your car working well. In this article, we'll explore the reasons why radiator hoses collapse, the signs to look for, and the steps you can take to prevent it from happening.

Common Causes of a Collapsed Radiator Hose 

The overarching reason that a radiator hose collapses is due to a vacuum that’s created in the cooling system. When that happens, it creates suction on the weakest or softest part of the system, which is one of the rubber hoses. However, the reason behind it can vary. 

1. Leaking coolant

A coolant leak can occur from anywhere in the cooling system: the radiator, water pump, thermostat housing, heater core, hoses, fittings, or even internally or externally from the engine. When the coolant level drops to the point where there’s an air gap in the cooling system and the engine is shut off, the cooling antifreeze and surrounding parts make the air contract too.

Like sucking on a milkshake that’s too thick to pass through the straw easily, the suction squishes the radiator hose down. Adding coolant can temporarily remedy the situation, although the leak will need to be dealt with.

2. Bad radiator cap

One of the most prevalent causes for a collapsed radiator hose is a radiator cap that doesn’t regulate the cooling system’s pressure properly. The radiator cap is designed to maintain a specific pressure level within the cooling system, which helps to prevent overheating. If the cap is damaged or not functioning properly, it may not be able to regulate the pressure, and lower pressure than normal can potentially cause the radiator hose to collapse as the engine cools.

3. Loose hose clamp

The radiator hoses fasten the ends of each hose airtight, and hose clamps at other places throughout the cooling system do the same thing. A loose clamp can allow air to be sucked into the cooling system or have coolant push out when the conditions are right. Then, when the engine turns off and there’s no longer that slight positive pressure inside, the hose can seal again, collapsing on itself in the same way as if there is a coolant leak.

Tightening the hose clamp and topping up the cooling system will often correct the condition.

4. Clogged hose or radiator

Imagine that corrosion, debris, or gelling coolant gather in a hose, a reduced fitting, or a thin tube through the radiator core. The water pump continues trying to circulate the coolant, but to no real effect. It creates suction on the side that supplies the water pump and the hose squeezes down, flattening along the least reinforced section which is usually a straight stretch of hose.

5. Wear and tear

The varying conditions in an engine – positive pressure and vacuum – are no problem for hoses that are in good shape. But once the rubber has begun to deteriorate and show signs of cracking, cuts, hardening, or bulges, it isn’t so resilient anymore. After several years and 60,000 miles or more, the hose may not be able to withstand those fluctuations. It can bulge, but more often, the hose will collapse.

Only a replacement hose can correct the effects of wear and tear.

How to Prevent a Radiator Hose From Collapsing

If you find your car overheating or there’s a hose that collapses when the engine’s off, attention is required somewhere. In most cases, the way to prevent it is by correcting whatever problem is causing the condition in the first place. That could be as simple as flushing the coolant to get rid of restriction-causing debris, changing a failed radiator cap, fixing a head gasket, or replacing the radiator or other components.

But if you stay on track with your car maintenance, you may be able to identify and correct issues before you encounter a collapsed hose. Here are a few good practices to include during an inspection at every oil change:

  • Keep an eye on the coolant condition and flush it if it’s acidic, isn’t strong enough, or has debris.
  • Squeeze each hose and ensure it bounces back immediately.
  • Inspect for cracks and cuts on the hoses.
  • Watch for high temperature warnings on the driver instrument cluster.

Trust AutoZone for your cooling system parts and fluids including radiator hoses and engine coolant. Get your parts fast the way it’s most convenient for you with online orders and in-store purchases along with Trustworthy Advice from AutoZone associates. If the job is too big for you, seek out one of our Preferred Shops to help you do the job.

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FAQ/People Also Ask 

How do I know if my radiator hose has collapsed?

If your engine is overheating, the coolant level is low, or the radiator hose has visibly flattened with the engine running or not, it’s a cause for concern.

Can I drive my car if the radiator hose has collapsed?

If your radiator hose has collapsed, the coolant flow is restricted and can quickly contribute to overheating. It’s not a good idea to drive your car in that state.

How can I prevent my radiator hose from collapsing?

Preventative maintenance for your cooling system is the best way to keep your radiator hoses in good condition for as long as possible.

How much does it cost to fix a collapsed radiator hose?

The parts you need vary depending on the cause. For the hose itself, $50 in parts is often all it takes for a DIY repair.

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