Heat, especially excess heat, is your engine’s worst enemy. And in a country like Australia where temperatures can regularly reach a blistering 45ºC, allowing your engine to overheat can be disastrous.
Your car’s radiator is its guardian against catastrophic temperature increases. It’s responsible for the critical heat exchange function that keeps engine temperatures in the green, and make no mistake: if it’s blocked, damaged, or clogged to the point where it can’t provide stable cooling, you could be on the path to a costly and catastrophic thermal failure.
In short, you need to be sure that your radiator, along with the rest of your car’s cooling system is performing as intended at all times. It begins, however, with an understanding of how your radiator works and it relies on a commitment to replace it quickly if it isn’t working as intended.
High-Pressure Radiators are the Ultimate Temperature Regulators
Believe it or not, if you’ve ever noticed that your car’s radiator resembles a sandwich, that’s precisely what it is. A modern, high-pressure car radiator is basically a core of aluminium tubes that are joined by either copper alloy or aluminium fins and sandwiched between a pair of reservoir tanks: one receives hot coolant from the engine, while the other collects coolant that’s ready to be pumped back into the engine.
What’s important to remember is that car radiators do more than just perform widespread engine cooling. Engines don’t like excessive heat, but heat is still an essential part of efficient combustion; that means in addition to protecting your engine from overheating, your radiator also has a role to play when it comes to:
- Bringing your engine safely up to operating temperature;
- Maintaining the engine temperature’s overall stability; and,
- Ensuring engine temperatures remain within their optimal operating range.
The fact is, no matter how high or low the ambient temperature goes, your radiator is still tasked with regulating engine temperature, and anything from tube or fin damage, to core-clogging coolant contamination can send your engine’s temperature skyrocketing. That’s why it’s crucial to be able to distinguish between the main automotive radiator types, and be prepared to replace yours if you recognize that you have a cooling problem.
How to Tell if Your Radiator is Downflow or Crossflow
Depending on the age and size of your car, there are two types of radiator that it might be equipped with either a downflow or crossflow style unit. They both perform the same cooling and temperature-regulating functions, but if you’re looking at direct replacement car radiators online, or are looking to upgrade your car’s radiator, you need to be aware of the distinctions between them.
Downflow radiators are usually found in older cars with horizontal grille patterns, and feature horizontally positioned reservoirs across the top and bottom of the tube core. Heated coolant moves from the high-pressure top tank to the low-pressure bottom tank with this type of car radiator cooling system, but they’re limited in cooling capacity by their height.
Inversely, the reservoirs on crossflow radiators are positioned along the sides of the core. These types of auto radiators move heated coolant horizontally, are found in newer cars, and are typically comprised of a larger frontal heat transfer area, and a wider, more densely populated core of tubing. These radiators make it possible for their pressure caps to be placed either on the low, or high-pressure side of the core: a simple leakage prevention advantage that downflow radiators don’t have.
The Special Function of Radiators With Transmission Coolers
If your car has an automatic transmission, it’s also possible that your car’s radiator has a built-in transmission oil cooler. Unlike independently mounted transmission coolers, transmission-plumbed radiators are designed to take advantage of the optimal positioning of the engine cooling radiator by:
- Putting the engine radiator’s large cooling core area to use;
- Putting the engine fan’s fresh-air draw to use; and,
- Eliminating the need to install an independent auxiliary transmission cooler.
Invariably, if your car is equipped with an automatic transmission and your radiator is damaged, you need to be concerned about the impact it could also have on your transmission. You need to be able to recognize the telltale signs of radiator damage, and any replacement or aftermarket radiator that you buy will have to have provisions for transmission cooling.
Recognizing the Signs That It’s Time to Replace Your Radiator
No matter how tempting it is to make it just with periodic top-offs, you can’t afford to ignore a damaged or failing radiator, especially if it’s plumbed for transmission cooling. The increased likelihood of a blown head gasket or a catastrophic part seizure due to extreme overheating means that the sooner you’re able to detect the symptoms of an impending radiator failure, the easier it’ll be to prevent an even costlier problem from happening.
Although you’d be hard-pressed to find a vehicle today that isn’t equipped with the temperature gauges and warning lights that would indicate overheating, it’s still important to be able to recognize the visual signs of radiator failure firsthand, including:
- White smoke, steam, or hissing noises under the bonnet;
- Sweet odour of coolant from under the bonnet or inside the passenger compartment; and,
- Green, red, or milky brown coolant under the vehicle.
The reality is, that the cost savings associated with repairing a damaged radiator rarely justifies the risk that you could be incurring if either that repair fails, or it causes yet another problem to occur. More often than not, if you recognize that your radiator is failing, your best bet is to flush your engine clean of any residual coolant, and invest in a new, aluminium-core radiator that has superior cooling and conductivity.
The Final Word
At the end of the day, it doesn’t matter what type of vehicle you have: a damaged radiator can mean instant trouble. Even short periods of overheating can lead to engine seizures, so it’s not a problem that you can afford to ignore.
When failure is imminent, a new, high-pressure car radiator is the best way to keep engine temperatures in the range that they need to be. Radiators aren’t expensive; and when you consider what an overheated engine could wind up costing you, a new core is a more than worthwhile investment.
