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.
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 and fix a coolant leak in your 1990 Nissan D21, start with a thorough visual inspection of the engine bay and the area beneath the vehicle. Look for any visible signs of coolant, such as puddles or stains, which can help you identify the general location of the leak. Once you have a potential area, perform a pressure test on the cooling system; this will help you pinpoint the exact source of the leak by pressurizing the system and revealing any weak spots. Next, carefully examine all hoses and connections for any signs of wear, such as cracks or bulges, and replace any damaged parts. Pay special attention to the radiator, as it can often be a source of leaks due to corrosion or damage. Additionally, inspect the water pump and heater core, as these components can also contribute to coolant leaks. Finally, check the head gasket for any signs of failure, as a compromised gasket can lead to significant coolant loss. Once you have identified the source of the leak, you can proceed with the necessary repairs or replacements to restore your vehicle's cooling system to optimal performance. By following this diagnostic approach, you can efficiently address the issue and prevent further overheating problems.
When dealing with coolant leaks in a 1990 Nissan D21, it's essential to understand the various components that may be at fault. One of the most frequent culprits is worn-out hoses, which can crack and leak over time due to exposure to heat and pressure. Additionally, a faulty radiator can lead to significant coolant loss, especially if it has corroded or sustained physical damage. The water pump, responsible for circulating coolant, can also develop leaks, which may go unnoticed until they cause overheating. Another area to inspect is the radiator cap; a cracked or improperly sealed cap can disrupt the system's pressure, resulting in leaks. Furthermore, the radiator core itself can suffer from corrosion or impact damage, leading to coolant escaping. Lastly, ensure that hose clamps are secure and undamaged, as loose or broken clamps can create gaps where coolant can leak. By systematically checking these components, DIYers can effectively diagnose and address coolant leaks, helping to maintain the health of their Nissan D21.
Addressing a coolant leak in your 1990 Nissan D21 is not just a matter of routine maintenance; it is an urgent necessity to safeguard your vehicle's engine and your safety on the road. Coolant plays a vital role in regulating engine temperature, and any leak can lead to overheating, which poses a significant risk of severe engine damage, including warped cylinder heads and blown head gaskets. These repairs can be financially burdensome and time-consuming. Moreover, a coolant leak can create immediate safety hazards, such as the risk of sudden engine failure while driving or even the potential for a fire if the leak is substantial. Additionally, low coolant levels can exacerbate overheating issues, further increasing the likelihood of catastrophic engine damage. Therefore, it is imperative to address any signs of a coolant leak promptly to avoid costly repairs and ensure your vehicle remains safe and reliable on the road.
See what others are asking about their Nissan D21. Get answers from RepairPal's community of auto experts and enthusiasts.
Read about related problems experienced by other Nissan D21 drivers like you.
