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.
To effectively diagnose a coolant leak in your 2014 Toyota Highlander, start with a thorough initial inspection of the vehicle. Look for visible signs of coolant, such as puddles or stains under the car and around the engine bay, as coolant typically has a sweet smell and distinct color. Next, check the coolant level in the reservoir, ensuring it falls between the "MIN" and "MAX" lines, which can indicate whether there is a significant leak. A visual inspection of the cooling system components, including the radiator and hoses, is crucial; pay close attention to connection points where leaks commonly occur. Cleaning the engine area can also help reveal smaller leaks that might be obscured by dirt. If these preliminary checks do not yield results, using a cooling system pressure tester can be an effective method to identify hidden leaks. By pressurizing the system, you can observe any pressure drops that indicate a leak. If necessary, introduce a UV dye into the coolant and inspect with a black light after running the engine, as this can highlight leaks that are otherwise difficult to see. Additionally, consider checking for combustion gases in the coolant, which may suggest more serious issues like a head gasket leak. If you still cannot locate the source of the leak, monitoring the vehicle on cardboard for a couple of days can help pinpoint the area of leakage. Should these DIY methods prove challenging or inconclusive, seeking a professional diagnosis is advisable, as mechanics have specialized tools to accurately identify and address coolant leaks.
When diagnosing a coolant leak in a 2014 Toyota Highlander, it's essential to consider several common problems that could be at play. One of the primary culprits is damaged hoses, which can develop cracks or wear over time, leading to leaks in the cooling system. Additionally, a faulty radiator may be responsible, as corrosion or physical damage can create leaks at various points, including the radiator cap. The water pump is another critical component; if its seals fail, it can result in slow leaks that may not be immediately noticeable but can lead to significant issues over time. Worn gaskets, particularly the head gasket, can also allow coolant to escape or mix with engine oil, while loose or corroded connections at hose fittings can exacerbate the problem. Furthermore, issues with the coolant reservoir, such as cracks, can lead to drops in coolant levels. Regular maintenance is crucial, as neglecting to change the coolant can lead to corrosion and increased leak potential. Lastly, factors like driving conditions and the vehicle's age can influence the likelihood of leaks, making it vital to conduct regular inspections to catch any issues early.
Not sure what's wrong?
Get help from a trusted expert
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
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.
Addressing a coolant leak in your 2014 Toyota Highlander is not just a matter of routine maintenance; it is an urgent issue that demands immediate attention. A coolant leak can lead to severe engine overheating, which poses a significant risk of catastrophic damage, including warping the engine head or cracking the engine block. These repairs can be financially burdensome, often costing thousands of dollars. Moreover, neglecting a coolant leak can result in the engine running out of coolant entirely, leading to a complete engine failure that could leave you stranded and facing even higher repair costs. Safety is another critical concern; driving with a coolant leak increases the risk of sudden overheating while on the road, potentially resulting in dangerous situations. Regularly checking your coolant levels and being vigilant for signs of a leak—such as a sweet smell or visible puddles—can help you catch issues early. If you suspect a leak, it is advisable to seek a professional diagnosis promptly, as the cost of diagnosis is relatively low compared to the potential expenses of extensive engine repairs. In summary, the urgency of addressing a coolant leak cannot be overstated; taking swift action is essential to protect your vehicle and ensure your safety on the road.
Read about related problems experienced by other Toyota Highlander drivers like you.
See what others are asking about their Toyota Highlander. Get answers from RepairPal's community of auto experts and enthusiasts.