If the engine runs too hot for too long, it can jam or crack, leading to repair costs of up to $10,000 in some models. For these reasons and more, it's best to deal with coolant leaks before they become serious.
Repair costs depend on the cause of the leak. For example, replacing a leaky heatsink washer can cost as little as $15. But if the leak is due to a blown head gasket, repair costs can be as high as $1,000 to $2,000 or more.
Before you can fix a coolant leak, you need to figure out what's causing it. In this guide, I cover everything you need to know about coolant leaks, including causes, repair costs, and more.
Broken Radiator
Your car radiator is located at the front of the engine for optimal airflow and cooling.
However, that also exposes it to more road dirt, debris from other vehicles, and more. If the radiator is punctured by corrosion or other damage, coolant may leak.
Repair cost
Replacing a leaky radiator clamp can cost as little as $15 if you do it yourself.
For cracks as small as hairs, radiator stopper products are very effective and cost less than $50. However, if you need to solder or need to replace the heatsink, it will cost you $1,000 to $1,500 or more.
Faulty water pump
Antifreeze can also leak due to a problem with the water pump, a belt-driven device that circulates coolant through the system. If coolant is low, contaminated, or belts are problematic, the pump can overheat and cause gaskets and seals to leak.
Repair cost
Estimates by RepairPal and Kelley Blue Book show water pump replacement costs ranging from $400 to $900.
If timing belts are an issue, costs are slightly lower from $367 to $756. The gaskets and washers can be replaced, but a simple pump replacement is often more feasible.
The radiator cap is worn out
Yes, even something as simple as a damaged or loose radiator cap can cause your car to leak coolant. Over time, gaskets in the lid can also dry out and crack, causing pressurized antifreeze to escape.
Repair cost
How much does it cost to repair a coolant leak caused by a leaky radiator cap? If the plug only needs tightening, the repair may not cost anything.
However, if you need to replace the cap, you can spend under $50 for a new one at the auto parts store.
Expansion tank cracked
The expansion tank, or coolant reservoir, is essentially a plastic container that holds antifreeze for the engine. It is located next to the engine and connects to the radiator via a rubber hose. If the reservoir is cracked or the hose is loose or broken, coolant will leak underneath your car.
Repair cost
In my experience, replacing an expansion tank typically costs $400 to $450, including about $60 to $80 in labor costs.
If the tank is in good condition but needs replacing the hose, the price ranges from $150 to $450 or more. You can also do these repairs yourself to reduce overall costs.
Blower head washer
The head gasket is what seals the connection between your car's engine block and the cylinder head so antifreeze can pass between them.
Head gaskets typically extend the life of the engine, but can dry out and crack if the engine is constantly overheated, causing coolant to leak out.
Repair cost
Replacing the head gasket is very expensive due to the lengthy repair time.
I estimate the average cost to be around $1800 to $2200. Of this amount, about $1,100 to $1,400 is spent on labor. For small cracks, you can also consider using a specialized head gasket sealer for $50 to $100.