5 Symptoms Of A Bad or Clogged Radiator and Replacement Cost

The radiator is cooling the coolant flowing through your engine. Here's how to tell your radiator is bad and how much it costs to replace it.

Symptoms Of A Bad Or Clogged Radiator

There are few components more well-known than your radiator. But while you might know where your radiator is, knowing how it works and how to tell when something goes wrong is a different story.

If you suspect that you have a faulty radiator, keep reading. I’ll cover the five most common signs that you have a defective radiator, how it works, where it’s at, and how much it costs to replace.

When you’re done reading, you’ll know for sure if your vehicle’s radiator is the problem, and you’ll be well on your way to getting repairs.

Moreover, just because you have a radiator leak or an overheating engine doesn’t mean it’s the radiator for sure. I’ll break down each symptom of a bad or clogged radiator and walk you through everything you need to know below.

Symptoms Of A Clogged or Bad Radiator

The most common symptom of a bad or clogged radiator is an overheating engine. You may also notice a coolant leak under your car or a fluctuating temperature gauge on your dashboard.

Here is a more detailed list of the signs of a bad or clogged radiator to look for:

1. High Temperature Gauge Readings

Overheating Engine E1609789863111

If you’re watching your temperature gauge get precariously high, that’s a sign that something is not working as it should. If the engine gets too hot, it’ll just shut off, which means that the problem has progressed to something a little more serious.

But an overheating engine can be a wide range of problems, including a faulty thermostat, a broken fan, or coolant leaks. You’ll need to do a little more troubleshooting to pinpoint the problem.

RELATED: 9 Causes of an Overheating Car Engine

2. Coolant Leaks

Car Leak

One of the most common problems with a faulty radiator is a leak. While you’ll usually see leaks underneath your vehicle, that’s not guaranteed. Take a look around your radiator. If you notice any white streaks or coolant puddles, then your radiator has a leak and needs repairs.

RELATED: How to Fix a Coolant Leak

3. Damaged Radiator Fins

Damaged Radiator Fins

Another common problem with radiators is damaged fins. Radiators sit at the front of your vehicle, but the fins are one of the easiest components to damage. While a few smashed fins won’t make your engine overheat, the more smashed fins you have, the less coolant flow you have in your radiator.

Additionally, smashed fins mean there’s a higher possibility that you have a leak.

4. Fluid Discoloration

One of the biggest radiator killers is corrosion. While corrosion shouldn’t be happening inside your cooling system, as the coolant wears down, the likelihood of corrosion building up increases.

Since the corrosion is on the inside of your radiator, you won’t be able to see it, but it will discolor the coolant. Try a coolant flush if your car’s coolant is old, but if it’s relatively new and already severely discolored, you have significant corrosion in your system.

Try a radiator flush to see if you can free up enough of the passageways, but be prepared, as you might have to replace the radiator.

5. Visible Corrosion

Visible corrosion is often the first sign that you’re about to have a more significant problem. Corrosion leads to blown seals, worn down fins, and a litany of other potential issues. While a little corrosion isn’t a huge deal, you should get your radiator looked at by a certified mechanic if there is an excessive amount.

The Function of the Radiator


The radiator is a critical part of your cooling system. As your coolant passes through the engine, it heats up. Given enough time and no cooling method, it will continue to heat up until your engine overheats and shuts off.

Your radiator acts as an integral part of the system that cools your coolant. The coolant travels from one side of the radiator to the other through the small metal fins you see. By thinning out as it goes through the fins, it becomes easier to cool.

Your vehicle does this with the help of an engine fan and by having air naturally flow over it as you drive. This is why the manufacturer puts your vehicle’s radiator at the front of your vehicle.

Radiator Location

Change Radiator

The radiator is one of the most straightforward components to find on your vehicle. It’s always located at the front of your vehicle. That way, it can utilize airflow as you drive to aid in the cooling process.

Typically, you’ll have your vehicle’s bumper/grill area, behind that you’ll have the fan, and behind that, you’ll have the radiator.

The condenser and the radiator look remarkably similar, but they’re not hard to tell apart once you know what you’re looking at. You can tell your condenser apart from your radiator in two ways. First, the condenser is in front of the radiator. Second, the heater core is often much thinner than your radiator.

When you’re locating your vehicle’s radiator, simply look for the larger of the two components and you’ll be in good shape. However, if you’re trying to gain access to your radiator, you might run into problems, as it’s often tightly packed between other components.

Radiator Testing

Radiator Replacement Cost

The average radiator replacement cost is between $550 and $800, depending on the car model and labor costs. While this is an expensive cost, the good news is that a mechanic can repair many radiator problems.

For instance, if one of the fins has a small leak, a certified repair shop can weld the leak shut, saving you a ton of money. Additionally, if the inside of your radiator is gunked up, a mechanic might be able to save it with a coolant flush for about $100.

Just keep in mind that if the flush doesn’t work, you might be in the same predicament and have to replace your radiator.

If you’re mechanically inclined and are trying to save a little money, you can replace your radiator yourself. While typically a little more involved, an aftermarket radiator typically costs between $100 and $200.

When you add in the price of the new coolant that you’ll need, you’ll likely spend around $250 to complete the repairs yourself. If you opt for an OEM replacement part, you can expect to spend a little more in parts compared to an aftermarket replacement.


How do you know if you have a bad radiator?

If your car overheats, it could be due to a bad radiator. It’s also common for the radiator to start leaking, so if you see any coolant leaking under your car, it could be a sign that the radiator is bad. A fluctuating coolant temperature gauge could also be caused by a clogged radiator.

Does a bad radiator affect performance?

The radiator does not affect a car’s performance per se. However, if your coolant temperature overheats, some modern cars’ engine control modules can limit the performance of the engine to prevent it from overheating, which would be fatal to it.

Is it safe to drive with a bad radiator?

No. It is not safe to drive with a bad radiator, whether it is clogged or leaking. If your car starts to overheat, it can blow the head gasket or cause even worse engine damage. So if your radiator is bad, it’s best to get it fixed as soon as possible.

How long does a radiator last?

The car’s radiator is made to last the life of a car. However, you can expect it to last 8 to 10 years, but it all depends on the climate you live in and how you drive and maintain your car.

Magnus Sellén
Written by:

Magnus is the owner and main author of Mechanicbase. He has been working as a car mechanic for over 10 years, and the majority of them specialized in advanced car diagnostics and troubleshooting. Certified Automotive Diagnostic Technician.

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