lowcoolantlevel ・ Photo by Wikimedia Commons
Most people don’t check the fluid levels in their cars as often as they should. Especially if a car is a newer model, most people just assume everything’s OK, or that a light will show up on the dashboard if anything is wrong. However, that’s not always the case, and as any car grows older, it needs a little more regular attention.
If you find that your car’s coolant level is down, there are a number of things that could be happening. We tend to suspect the radiator first because that’s where the coolant goes in, right? But in fact there are several places to look that are more likely than a leaky radiator. Let us give an important warning: Never open a radiator or any part of the cooling system when the engine is hot. The system is pressurized, and boiling hot water will shoot out of the opening. That can cause serious injuries.
Start looking for leaks when the engine is cold. You don’t want to stick your hands into a hot engine bay! Some clues to look for include:
Be sure to run your hand along the underside of the radiator and the underside of all the radiator hoses. Sometimes a slow leak isn’t enough to make a puddle, but you’ll lose coolant over time.
If you don’t find anything when the engine is cold, you can drive your car for a bit and let it come up to temperature. Sometimes you can spot a leak when the cooling system is under pressure. Just keep your hands away, because that coolant will be very hot!
Modern cars have an overflow reservoir that holds some extra coolant. The system is designed so that if any coolant pushes past the radiator cap, it goes into the reservoir. Then when the engine cools, some coolant in the reservoir goes back into the engine.
The reservoir is not usually pressurized, but check to see if it’s leaking, or if the tubes that connect the reservoir to the radiator may be leaking. There are always minimum and maximum marks on the side of the reservoir to indicate the correct coolant level.
There are several locations in your car’s cooling system where leaks tend to occur. These locations include:
These places are less likely to be leaking, but if you haven’t found the leak, they’re worth checking.
If you look all over the outside of your engine and can’t find anything, it could be a head gasket problem. However, this is a rare problem, so it’s unlikely and should be diagnosed by a professional.
Here’s how it works: As the coolant circulates through the engine, some of it goes up into the cylinder head to cool that part of the engine. If the gasket between the engine block and the head starts to leak, some coolant can end up in the cylinders, or in the engine’s oil system. You can usually tell a head gasket problem if you’re seeing a lot of steam come out the exhaust pipe, or if you find engine oil floating in the coolant reservoir. You can also check the oil. If it looks like a milkshake, you’ve got coolant in your oil. Consult a good mechanic immediately if you find any of these conditions.
If you look all the way around your engine and you can’t find any leaks, or any sign of a leaky heating system or head gasket, you have two options. The first is to carry some coolant around in the trunk and check your car’s coolant level frequently. Many people with older cars do this. You do run the risk of getting stranded someday with this strategy. Pro tip: Make sure you use the right kind of coolant for your car. Some brands require special coolant, and using the wrong product can damage your car. Check your owner’s manual to be sure.
The other option is to take your car to a professional mechanic. They’ll pressure-test the cooling system and should be able to track down the reason for low coolant levels. This costs some money, but it’s really the better option if you want to keep your car running at its best.