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Air Bubbles In The Cooling System: Not As Harmless As They Sound

by Jacob Scott

If you're a new trucker, still getting used to being out on the open road by yourself, you know that keeping an eye on how everything in the truck is working is essential both for safety and for your own peace of mind. No matter how much training you have, finally driving a semi truck can still be nerve-wracking, and knowing that your truck is running well can keep you calm. So if you see something alarming start to happen, you're going to want to know what it is and why it's happening. One thing you might see is a sudden spike in your temperature gauge. Chances are this is due to an air bubble in the cooling system. As harmless as that sounds, it can have repercussions, and you need to get the cooling system checked out quickly.

Bubbles Cause a Lack of Coolant

Your cooling system keeps your truck engine cool by running coolant through the system. If no coolant appears in part of the system, that part will start to get very hot. Your truck's thermometer will register that as overheating, and you'll see the needle on your dashboard gauge fly up.

With an air bubble, that rise is sometimes very temporary, indicating that the bubble's moved on. You might see this if the bubble is due to a random bit of air that got into the system when the radiator was last drained. Other times, though, the bubble stays where it is, creating a major overheating risk that can ruin your engine. You can see this if the air bubble is due to a constant leak in the system. However, it's impossible to tell which one it is unless you have someone check out the system. So, if you see your temperature gauge spike suddenly, don't assume it's a harmless blip.

Overheating Causes More Damage Than You Ever Want to See

If you ignore the spike, it could happen again and again until your engine overheats and blows out the radiator. A number of engine components can crack or sustain other damage when this happens. As annoying as having to get the engine checked can be, it's a lot more cost-effective -- and safer -- than taking a risk and seeing your truck's engine destroyed.

There's not much you can do to prevent a bit of air from getting trapped when having work done on the radiator, other than ensuring the repair techs you go to are skilled and try to do the best they can to protect the system. But you can prevent or stop leaks and cracks by having your cooling system and engine inspected frequently. You want to ensure that there are no parts that look like they are about to crack or come loose. Talk to your regular truck mechanic about a suitable maintenance schedule given how much you'll be driving.