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:
» 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
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.
To effectively diagnose a coolant leak in your 2015 Mercedes-Benz ML350, start by inspecting the coolant reservoir located under the hood. Look for any visible signs of leaks or low coolant levels, as this can indicate a problem. Next, examine the engine area for any obvious signs of coolant dripping, which can help pinpoint the source of the leak. Pay special attention to the radiator, as leaks often occur here; check for any cracks or wet spots that could suggest a failure. Additionally, inspect the head gasket for signs of damage, such as overheating or coolant mixing with oil, which can signal a more serious issue. By following this methodical approach, you can identify the source of the coolant leak and determine the necessary steps for repair.
When diagnosing a coolant leak in your 2015 Mercedes-Benz ML350, it's crucial to understand the common problems that can arise within the cooling system. One of the most frequent culprits is the deterioration of hoses, which can develop cracks or become brittle over time, leading to leaks. Additionally, the water pump is another critical component that can fail, causing coolant to escape. Regular inspections of these parts can help you catch potential issues early. If you notice any signs of coolant leakage, such as puddles under your vehicle or a drop in coolant levels, it's advisable to investigate these areas promptly. Addressing these common causes not only helps in maintaining your vehicle's performance but also prevents more severe engine damage down the line.
Addressing a coolant leak in your 2015 Mercedes-Benz ML350 is not just a matter of routine maintenance; it is a pressing concern that requires immediate attention. Ignoring a coolant leak can lead to severe engine overheating, which may result in catastrophic damage to vital engine components. As the coolant level drops, the engine's ability to maintain optimal operating temperatures diminishes, increasing the risk of engine failure. Furthermore, a persistent leak can escalate into more significant issues, leading to costly repairs that could have been avoided with timely intervention. For DIY enthusiasts, recognizing the urgency of this problem is crucial, as prompt action can safeguard your vehicle's performance and longevity, ensuring that you avoid the pitfalls of neglecting such a critical system.
Read about related problems experienced by other Mercedes-Benz ML350 drivers like you.
See what others are asking about their Mercedes-Benz ML350. Get answers from RepairPal's community of auto experts and enthusiasts.