How to Recognize When a Radiator Needs Replacing

by Erin MartiseUpdated July 10, 2023

How to Recognize When a Radiator Needs Replacing. Many car owners use a variety of quick fixes, such as leak sealing products or duct tape, to get a few extra miles out of an old radiator. In the long run, however, replacing the whole radiator is the only solution. Recognizing the difference between a radiator that needs to be repaired and one that needs to be replaced can prevent roadside breakdowns.

Things You'll Need:

Garden hose
Cold water

1. Flush it out

Flush it out. Drain the coolant and flush the radiator with cold water by sticking a garden hose in both the opening at the radiator cap and underneath the radiator in the lower fluid outlet. If your radiator still leaks even after engine deposits and debris have been removed from the inside of the radiator, then replacing the entire unit is your best bet.

2. Inspect the exterior of the radiator for excessive rust

Inspect the exterior of the radiator for excessive rust, which may indicate irreversible damage to the core. Seeing the occasional rusty water stain on the side of the radiator may not indicate any real damage, but if the metal is starting to flake and chip, or if fittings cannot be removed due to excessive oxidation, then it's time to replace the radiator.

3. Replace the radiator if you need to continually add water or coolant on a regular basis

Replace the radiator if you need to continually add water or coolant on a regular basis. Even if you don't see signs of a leak, fluid may still be escaping by turning into steam. This indicates that your cooling system is not doing its job, and that an overheated engine is right around the corner.

4. Recognize that it's time to replace your radiator

Recognize that it's time to replace your radiator and all of the hoses if your car is overheating repeatedly, despite any precautions you have taken to reduce leaks. Duct tape and leak sealers are only temporary solutions, and should only be used in emergency situations. If you have to keep reapplying these methods, it's time to replace the radiator.

5. Use online resources to learn more about your car's cooling system

Use online resources to learn more about your car's cooling system and how to perform basic maintenance on radiators.

Tips

Always check the radiator hoses for sponginess or brittleness before you blame the radiator for leaks. If the leak is coming from the hose or a hose fitting, it will be much less expensive to replace than an entire radiator.