Guidelines for replacing car hoses in 7 easy steps

Today's engines are compact and more powerful than ever before. They generate a lot more heat inside engine compartments, where the space available is being reduced.

When to replace coolant hoses

When inspecting cooling system hoses, a four-year replacement cycle is the basic rule of thumb, but is by no means precise. Vehicles operating under severe conditions or vehicles that are not driven often may require more frequent replacements. Therefore, it is imperative to periodically inspect hoses – even hoses less than four years old – for damage from the major hose enemies electrochemical degradation, leakage, heat, ozone, abrasion, and oil contamination whenever a vehicle comes in for service.

It should be noted that the number one cause of cooling system hose failure is electrochemical degradation. This is an electrochemical attack from the inside of the hose. It is impossible to detect this from a visual inspection of the hose. In our problem diagnosis section of this site you can read all about how to detect electrochemical degradation and how to prevent it.  

Here below you can find general guidelines on how to replace car hoses. However, remember to always refer to the vehicle manufacturer's recommended procedures for replacement and maintenance of coolant hoses.

How to replace hoses in 7 easy steps


Safety first
Always wait until the engine is cool before working on any part of the cooling system.


Loosen the clamp and remove the old hose. Use Gates handy GAT6060 and GAT6065 tool kits for removing and installing hose clamps and clips. Most hoses should gently twist off the fitting once the clamp is loosened. A rusted clamp can be carefully cut and removed with tin snips. If the hose is stuck to the fitting, do not force or pry it off. Doing so could damage the fitting. Instead, carefully cut the hose lengthwise, then peel the hose off the fitting.


Check the nipple for sharp edges or burrs. It is best to clean the fitting with a wire brush to make sure it is clean and smooth.


Before installing the new hose, inspect the other cooling system service parts: thermostat, water pump and pressure cap(s).


Install the new hose. Slip the new clamp onto the hose and then push the hose onto the fitting, installing the engine end first. Lubricating the nipple with a small amount of washing-up liquid will make it easier to push the hose onto the fitting, without affecting the hose quality.
Check that the hose is shouldered well beyond the edge of the fitting.  

Caution: hose clamps come in very different types, each designed to meet different hose specifications so make sure you install the correct style and size of clamps.


Proceed and tighten the new hose clamps. Clamp the hose into position between the nipple and the hose end.

Caution: a clamp tightened over the nipple will eventually cut the hose tube.


Do a final visual inspection to ensure there are no leaks after the cooling system refill.
Keep in mind that some leaks will become obvious when the engine is cold, but others only when it is hot.