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.
When troubleshooting coolant leaks in a BMW 335i, start by examining the most visible and accessible components of the cooling system. Begin with the hose connections, as loose or damaged hoses are often the simplest issues to resolve. Next, inspect the radiator for any signs of cracks or leaks, as this is a common failure point. Pay close attention to the water pump, which can also be a source of leaks if it has failed. If these initial checks do not reveal the problem, move on to the more challenging areas, such as the vent hose connecting the upper radiator hose to the coolant reservoir, as this connection is particularly vulnerable. Additionally, check for leaks between the radiator and the engine, especially on the driver’s side, where coolant may spray onto the serpentine belt, causing further complications. By systematically assessing these components, you can effectively identify and address coolant leaks, ensuring your BMW 335i operates smoothly and preventing potential engine damage.
When tackling coolant leaks in a BMW 335is, it's essential to understand the common problems that can arise within the cooling system. One frequent issue is the failure of the water pump, which can lead to leaks due to wear and tear over time. Additionally, the radiator may develop cracks or corrosion, especially in older models, resulting in coolant escaping. Hoses are another critical area to inspect; they can become brittle and develop leaks at connection points or along their length. The expansion tank is also a common culprit, as it can crack or fail, causing coolant to leak. By being aware of these potential failure modes, you can more effectively diagnose the source of the leak during your visual inspection. This knowledge not only aids in identifying the problem but also helps you prioritize repairs, ensuring that your BMW 335is remains in optimal condition and preventing further engine damage.
Addressing a coolant leak in your BMW 335i is crucial not only for the longevity of your vehicle but also for your safety on the road. Ignoring the symptoms of a coolant leak can lead to severe engine overheating, which may result in costly repairs or even engine failure. Start by identifying the source of the leak, as common culprits include loose hose connections, a damaged radiator, or a malfunctioning water pump. Regularly checking your coolant level is essential; if you notice it dropping below the recommended levels, it’s a clear indication that something is amiss. Inspect the engine bay for visible signs of coolant, such as puddles or spray, particularly around the thermostat, hoses, and radiator. Pay special attention to the vent hose connecting the upper radiator hose to the coolant reservoir, as this area is prone to leaks. If you find any damaged components, prompt repair or replacement is necessary to avoid further complications. By taking these steps, you can effectively manage a coolant leak and maintain the health of your BMW 335i, ensuring a safe and reliable driving experience.
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