2017 Mazda CX-5 Has A Coolant Leak

Diagnosing Coolant Leak Issues in Your 2017 Mazda CX-5 and Effective Repair Strategies

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Reviewed by
Devin Cabugcal
Written by RepairPal Car Genius
Updated January 14, 2025
0%
50% chance it's the
Loose Hose Connections
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25% chance it's the
Radiator
0%
25% chance it's the
Water Pump
The most common reasons a 2017 Mazda CX-5 has a coolant leak are loose hose connections, a broken radiator, or a failed water pump.
  • Loose Hose Connections: A loose hose connection can lead to vacuum leaks or fluid loss, resulting in poor engine performance or overheating.
  • Radiator: A damaged or clogged radiator can impede coolant flow, resulting in engine overheating and reduced cooling efficiency.
  • Water Pump: A failing water pump can lead to coolant leaks or overheating due to inadequate circulation of coolant in the engine.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2017 Mazda CX-5 has a coolant leak?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

When the head gasket begins to fail, the engine may have no symptoms at all. They only begin to occur when the leak has reached an engine oil passage, engine coolant passage or the engine cylinder.

When that happens, the engine may be very difficult to start, and run roughly when idling. There may be oil or coolant leaking, and the engine may begin to overheat, or at least run hot. At this point, there may be coolant in the engine oil pan — this will look creamy and lighter in color than the oil. Also, the radiator or engine coolant reservoir may have a gurgling sound, the presence engine oil, or smell of combustion. And the check engine light will come on.

The coolant being burned in the engine will produce white exhaust that smells sweet, like engine coolant. When the head gasket fails completely, the engine will overheat within minutes of starting, will stall and then won't restart.

A failing heater core may cause the car's interior to smell like engine coolant. The smell will become worse when the heater is turned on. The engine may also begin to run hotter until the vehicle is repaired.

The worst-case scenario is the engine overheating, which can cause extensive engine damage.

If the heater core is clogged, the air that blows when the heater is turned on will not be very hot.

Problems with the intake manifold gasket can create the following symptoms:

  • Illuminated check engine light
  • Erratic engine performance
  • Oil and coolant leaks
  • Poor gas mileage
  • Stalling

» LEARN MORE: Intake manifold gasket symptoms

A failing radiator can cause the engine to run hot or overheat. Most radiators are made of metal and plastic. The plastic parts can become brittle and crack over time, causing a leak of coolant (typically green or pink in color). All manufacturers have a recommended service interval for coolant renewal. As the coolant ages, the additives breakdown and being to form solid deposits. These deposits will build up in the passages of the cooling system and will eventually clog components, including the radiator. A leaking or clogged radiator must be replaced. Some automatic transmission cars will also have a transmission cooler integrated into the radiator. Lines going to and from the transmission circulate transmission fluid to help cool the transmission in heavy duty applications such as towing or off-roading. If this integrated cooler fails, it can allow transmission fluid and coolant to mix. This will causing shifting issues in addition to overheating.

A coolant leak may be noted from the hoses. Coolant hoses can be damaged by oil leaks, or age. This will lead to swelling or cracking, it is suggested to replace the hoses before they begin leaking to avoid potential overheating.

The bad thermostat can cause two different sets of problems, depending on whether it's stuck open or stuck closed.

A thermostat that is stuck open can cause the engine to run colder than normal and turn on the check engine light. It may also cause poor fuel mileage and the heater to blow cool air.

A thermostat that is stuck closed will cause the vehicle to overheat. If a new thermostat doesn't resolve engine temperature problems, the cooling system needs to be checked for other issues.

» LEARN MORE: Signs of a bad thermostat, and how to fix it

If a vehicle is overheating, a bad thermostat could be the problem, and a damaged thermostat housing is more likely to produce a coolant leak, either from a cracked or warped housing or a failed seal to the engine. The thermostat housing can be made of metal or plastic. And the housing can be a stand-alone part that is separate from the thermostat, or (on later model vehicles) can be integrated with the thermostat and replaced as a single unit.

The two most common signs of a bad pump are leaks and noises.

Leaking water pumps can result in damage to the drive and timing belts, and cause the engine to overheat. A failed water pump can be caused by other problems in the cooling system, such as a bad thermostat, radiator or head gasket.

What are the initial diagnostic steps to identify the source of a coolant leak in a 2017 Mazda CX-5?

To effectively identify the source of a coolant leak in your 2017 Mazda CX-5, start with a thorough visual inspection of the vehicle's undercarriage and engine bay. Look for any visible signs of coolant pooling or staining around critical components such as the radiator, hoses, and water pump. Next, check the coolant levels in both the reservoir and radiator; a significant drop can indicate a leak. If these initial checks do not reveal the issue, consider performing a pressure test on the cooling system, which can help pinpoint leaks by pressurizing the system and revealing weak spots. Additionally, inspect the radiator for corrosion or damage, and examine the hoses for any signs of wear, such as cracks or bulges. Don’t forget to check the water pump for leaks, as a malfunctioning pump can also contribute to coolant loss. Lastly, if you suspect the leak might be inside the vehicle, inspect the heater core, especially if you notice a sweet smell or coolant inside the cabin. By following this structured diagnostic approach, you can efficiently identify and address the source of the coolant leak in your Mazda CX-5.

What are the common causes of a coolant leak in a 2017 Mazda CX-5?

When dealing with coolant leaks in a 2017 Mazda CX-5, it's essential to understand the common culprits that could be causing the problem. One of the primary issues is damaged hoses, which can develop cracks or wear over time, leading to leaks in the cooling system. Additionally, a faulty radiator may be at fault; corrosion or physical damage can compromise its integrity, resulting in coolant escaping. Another potential source of leaks is the water pump, which is responsible for circulating coolant throughout the engine; if it malfunctions or develops a leak, it can lead to significant coolant loss. Don't overlook the radiator cap, as a cracked or faulty cap can also allow coolant to escape. Furthermore, loose or damaged clamps that secure the hoses can contribute to leaks, as they may not hold the hoses tightly enough. Lastly, a leaking heater core can cause coolant to seep into the vehicle's interior or onto the ground, indicating a more serious issue. Addressing these problems promptly is crucial to prevent overheating and potential engine damage, making it advisable for DIY enthusiasts to inspect these components regularly.

How urgent is it to address a coolant leak in a 2017 Mazda CX-5?

Addressing a coolant leak in your 2017 Mazda CX-5 is not just a matter of convenience; it is a crucial step in maintaining the health and safety of your vehicle. Coolant plays a vital role in regulating engine temperature, and a leak can quickly escalate into severe overheating, leading to catastrophic engine damage. For DIY enthusiasts, understanding the urgency of this issue is essential. Ignoring a coolant leak can result in the engine running excessively hot, which not only risks engine failure but can also lead to costly repairs that could have been avoided with timely intervention. Additionally, a coolant leak can diminish your vehicle's performance and fuel efficiency, making it imperative to act swiftly. By addressing the leak early, you not only safeguard your engine and cooling system but also save yourself time and money in the long run. Therefore, if you notice any signs of a coolant leak, it is advisable to investigate and resolve the issue as soon as possible to ensure your Mazda CX-5 operates safely and efficiently.

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2017 Mazda CX-5 Coolant Leak Causes & Repair Costs