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7 Bad Radiator Symptoms You Should Know

August 9, 2022

Your radiator is one of the most important parts in your car. It has two vital jobs: keeping your engine from overheating, and keeping coolant properly circulating through your cooling system’s lines. Bad radiator symptoms can easily fly under the radar though, which can lead to more complicated engine problems later on, which can result in expensive radiator repair fees. 

Radiator hose replacements are less expensive than a full-stack replacement, but can still result in excess and avoidable costs. Read on to learn about the seven bad radiator symptoms you should know to keep your costs down and your car running. 

1. Rough shifting or grinding 

Rough shifting is often one of the first signs of radiator issues, and occurs when the transmission fluid mixes with the thick coolant. This can lead to grinding or otherwise rough shifting, which can indicate cracks in the housing. 

2. Overheating 

Your vehicle can overheat in unsavory driving conditions or due to a lack of coolant. However, temperamental overheating or spontaneous overheating can point to radiator dysfunction. 

Your radiator is responsible for keeping the engine cool via proper circulation of coolant through the lines. If there’s a problem or break somewhere in the system, you’ll notice more frequent instances of overheating, especially in situations where there wouldn’t be a secondary cause – such as winter or during regular driving excursions. 

3. Abnormally low coolant levels 

You’ll have to replace your vehicle’s coolant several times over its lifetime, flushing the lines approximately every 30,000 miles. Depending on your driving habits, this averages to be every 1-3 years – and you may opt to do it sooner depending on how you use your vehicle. If you notice yourself filling up sooner than that, it could indicate radiator issues or insufficiency. 

4. High temperature readings 

Persistently high temperature readings are also one of the most common bad radiator symptoms. This can indicate inefficient coolant use or failure to retain coolant, which can lead to overheating and damage in your engine. 

Keep an eye on the temperature gauge while driving. If you notice it climbing into the red zone with little to no engine strain, there’s a good possibility that your radiator is struggling. 

5. Radiator sludge 

Coolant should never be sludgy. Normally, it’s vibrantly colored and maintains its liquid properties at every point in its cycle. If you notice sludgy, discolored buildup in your radiator or around the area, this could mean that there’s a leak in the system or ineffective use of your radiator due to failure or other problems. 

6. Heater malfunction 

Your radiator can affect your vehicle’s heater – specifically the passenger heater. The cabin heater works with the efficient cycling of coolant in the heater core system, resulting in a warm burst of air that is expelled through the vents. Clogs or leaks result in little to no heater function, as there is not enough coolant cycling to result in warmer air, in those cases. 

7. Corrosion 

Coolant shouldn’t normally eat away at metal or cause corrosion. In fact, it has chemical components called inhibitors to keep it from doing that. However, if you go excessively long times between flushes, you could see some sludge or corrosion form due to the breakdown of these inhibitors – which can lead to cracks or leaks on your coolant system. 

What happens if you have a bad radiator? 

If you have a bad radiator, this means that your radiator isn’t working as well as it should – likely resulting in engine malfunction or overheating. If you choose to continue driving with a bad radiator, you may sustain more permanent engine damage, or higher risks of stalls or accidents.

How do you know if you need a new radiator? 

If you notice excessive temperature irregularities or your engine overheats regularly, you may need a new radiator. It’s important to seek professional diagnostic support to ensure that you aren’t misdiagnosing a different problem, and to help you to get the care you need for your vehicle’s maintenance. 

How do you test if your radiator is working? 

You can test your radiator for blockages, which can help you to assess how well it’s working. First, check your system using our system checklist above. Are there any signs of malfunction? If so, you may want to move onto more in-depth diagnostics such as a radiator cap test. 

Convenient auto repair at home 

Looking for a convenient auto repair solution? Consider the team at RepairSmith. Our experts come to your home and take care of vital services your car needs to function properly. For more information, please connect with us today.