How Does a Radiator Work?

Your engine produces a lot of heat. Fortunately, coolant keeps it from overheating. As it flows through and around the engine, the coolant absorbs the heat and carries it to the radiator.

When it reaches the radiator, the coolant flows into tubes. The car’s movement forces air through the rows that run between the tubes, cooling down the coolant as it goes. This dissipates the heat through the vehicle’s grille, and then the coolant is run back into the engine to continue cooling it. As long as the radiator is able to dispel heat quickly enough to keep the coolant efficient, the engine is able to run without overheating.

If the radiator isn’t running efficiently, or isn’t adequate for the horsepower being produced, the engine will overheat.

When to Replace a Radiator

Radiators tend to last 8-10 years if they’re properly maintained. People generally only need a new radiator if theirs has been damaged or if they need a more powerful one.

Common Radiator Problems

Pressure Problems

If your radiator cap goes south, you could have issues with either too much or too little pressure in your radiator. Either problem ends the same way: your engine overheats. In this instance, you could just replace your radiator cap.

Pressure problems can also be caused by leaks, and leaks can be caused by pressure problems. At a shop, they can test the radiator’s pressure to see if this is the issue.

Leaks

Coolant leaks aren’t just annoying, they’re also dangerous. Antifreeze is extremely toxic, and has killed more than one household pet. If you see a leak, it may not mean you need to replace your whole radiator. Most of the time leaks are caused by older hoses, but sometimes leaks can be caused by cracked radiators, failing water pumps, or other unusual causes.

While a leak indicates that something isn’t working and that you should check your hoses, problems at any point in the cooling system can cause a loss of pressure and subsequent leak.

Rust and Corrosion

What if you haven’t upgraded your engine but it just randomly started overheating? Well, it’s likely due to rust, debris, or other ‘junk’ preventing your radiator from operating the way it should. In this case, you’ll need to flush out your radiator or consider swapping in a new one.

At least once a year, you should make time to clean your radiator as a way of preventing this. You can also invest in an aluminum radiator, which is less susceptible to corrosion.

Upgrading Your Radiator

The other reason to replace a radiator is a lot more fun. As you start adding cold air intakes and tuning your engine, it’s going to produce more horsepower. And more horsepower leads to more heat. To protect your engine you’ll need to improve the radiator to keep up.

When it comes to replacement radiators, you’ll quickly find that you have a lot of options.

Key Features of Car Radiators

There are a lot of factors to consider if you’re purchasing a replacement radiator. Here are some of the top features to consider before selecting a new radiator for your vehicle.

Radiator Size

Bigger is better. At least with radiators. A larger radiator will have more surface area which allows for faster cooling. But before you rush out and buy the biggest radiator available, consider this:

• Underhold Space – Engine bays are usually cramped. The more limited the space is, the less airflow you have. That’s the opposite of what you want. Pick a radiator that will fit in the space you have available.
• Construction – It’s possible to get more cooling area in a smaller package. Choosing a radiator with more rows or one that’s made out of aluminum can give you the same cooling power as a larger unit.

Radiator Rows

In a radiator, coolant flows through tubes and over fins. Adding rows increases the total surface area fluid can flow over. This usually means faster cooling. Row number needs to be balanced with tube width to calculate for total cooling. A 2-row radiator with 1-inch tubes will cool more quickly than a 3-row radiator with ⅝-inch tubes.

One downside to adding rows is that it can make a radiator thicker, which restricts air and reduces cooling capability.

This is one of the many issues that has been helped by making radiators out of aluminum rather than copper-brass. Aluminum radiators can have more rows and wider tubes without adding significant thickness or weight.

What Type of Car Radiator Do You Need?

Now that you know the key features to look for in a new radiator, it’s time to decide which one to go with. There are radiator options for any kind of driver. Which will work best depends on you and your build.

Daily Driver

If you’re looking for a replacement radiator for a vehicle with no modifications, the stock radiator is usually the best choice. It’s easy to install, won’t require any modifications, and has already demonstrated its ability to adequately cool your engine.

You may also want to consider a stock replacement for a classic vehicle if you’re trying to be period-correct.

Functional Upgrade

If you’ve upgraded your stock equipment, then you’ll want an aftermarket radiator designed to accommodate more power.

For classics, simply upgrading to a radiator with an aluminum core will make a huge difference. Even when sized to be a direct replacement, they offer better cooling power and lighter weight.

Most vehicles made after the 1980s will already have an aluminum radiator, but increasing rows or investing in a larger radiator can improve cooling power.

Performance Radiators

Performance radiators can increase your coolant capacity and surface area for faster cooling. While some of these radiators require modifications to fit, they offer major cooling advantages.