A car smelling coolant but no leaks detected can make any driver panic. This issue may indicate an internal leakage due to worn or damaged components. Things may worsen if the coolant level decreases and the car begins to overheat.
On the upside, if you can’t spot any coolant leakage, there’s a chance the issue is still in its early stages. You can prevent further damage by diagnosing and fixing the root cause of the problem immediately.
Herein, I’ll help you discover why your car smells like coolant but no leak and how to address the problem. You’ll also learn the symptoms to look for when this issue occurs.
But first, let’s see why coolant is vital for your vehicle.
Question: Why Does Your Car Need Coolant?
Coolant, also called radiator fluid or antifreeze, is critical to your car’s engine cooling system. It runs through the engine to keep it within the correct operating temperature and prevent overheating.
Also, coolant lubricates certain moving parts along the way. As a result, this fluid prevents premature wear or damage to the head gasket, water pump, piston, and cylinder. Lack of coolant can cause these parts to corrode, release deposits, and clog the passageways.
Coolant acts as an antifreeze during winter. It lowers water’s freezing point to prevent it from freezing during the cold months. If water freezes in the engine cooling system, it forms a crystal lattice, hampering the cooling process. As a result, the engine overheats, and parts get damaged.
Worn-out or damaged parts in the cooling system can cause coolant leakage. An internal coolant leak is often hard to detect, especially while driving. You may notice a sweet aroma from the engine bay but fail to detect leaks.
Answer: Signs of Internal Coolant Leak
An internal coolant leak may cause your car to smell coolant but no leaks. As mentioned above, the sweet aroma from the vehicle after driving indicates a coolant leak. You can smell it in the cabin or after moving out of the car.
Besides the smell, other symptoms of an internal coolant leak include the following:
White Smoke From the Exhaust
Exhaust smoke can let you know if your car has a problem. Smoke from the exhaust may range from black, blue, and white.
Seeing your car’s exhaust emitting white smoke could indicate coolant leaking into the combustion chamber.
The combustion chamber burns off this coolant and releases it through the exhaust as white smoke. You’ll likely see this smoke while starting the engine or during acceleration.
White Smoke Under the Hood
Coolant can leak and burn in the engine bay as white smoke. So, if your car smells like coolant but no leak, check the engine compartment. An overheated engine will force coolant out of the system. This coolant may land on the overheated parts and burn as white smoke.
Low Coolant Level
Does the coolant level in the reservoir keep dropping after refilling? If this happens, but you can’t detect a leak, your car might have an internal coolant leak.
Unusual Engine Performance
Various engine performance issues can indicate an internal coolant leak. The most common performance issues include the engine overheating, loss of power, poor gas mileage, and dashboard warning lights. Note that these issues could also indicate other problems with your auto.
Question: Why Does My Car Smell Like Coolant But No Leak?
Below are the reasons your car smells like coolant, but you can’t detect any external leaks.
- Blown head gasket
- Faulty radiator cap
- Punctured radiator
- Cracked heater core
Answer: Blown Head Gasket
Your car’s head gasket seals the combustion chamber and prevents coolant from entering the cylinders. Overheating or age can cause the gasket to blow or wear out and leak coolant into the combustion chamber.
A broken head gasket doesn’t leak coolant to the ground. So, if you can’t detect any leak externally, the most obvious sign will be the smell of exhaust smoke. The damaged gasket will allow coolant into the combustion chamber, where it’ll burn and escape through the exhaust as white smoke.
Besides the white smoke from the exhaust, you may notice a sweet aroma from the engine compartment. The only way to fix this issue is to replace the damaged head gasket.
Answer: Faulty Radiator Cap
The radiator cap (radiator pressure cap) helps to keep the pressurized hot coolant within the radiator. It ensures the coolant pressure remains around 13 to 16 PSI. If the pressure goes out of this range or what the manufacturer recommends, the cap may give in to the excessive force and allow the coolant to leak.
Besides, the radiator cap wears out over time and causes coolant to leak. Coolant leaking from the radiator may drip on the heated engine. The burning coolant will emit a sweet aroma and white smoke from the engine bay.
Before fixing the faulty radiator cap, ensure that no overflow in the coolant reservoir causes an increase in pressure. Then, replace the radiator pressure cap and tighten it correctly.
Always check the manufacturer-recommended pressure rating when replacing the radiator cap. Installing a higher-PSI radiator cap than the original can expose your radiator to more pressure. The excessive pressure may strain or damage parts like hoses, gaskets, heater core, and water pump seal.
Answer: Punctured Radiator
A punctured or cracked radiator could be why your car smells like coolant but no leak. Over time, rust and corrosion can accumulate on the radiator and cause it to wear out. This is one of the maintenance problems that can cause defects in the radiator.
If you fail to clean the radiator, dirt and sludge accumulate and cause rusting. Rust eats up the metal surfaces and causes leaks. Moreover, radiator pipes may wear out and leak coolant to the engine.
When coolant from the radiator or pipes lands on an overheated engine block, it may burn and emit white smoke. You may also notice a sweet scent of the heated coolant when you go near the engine bay.
Unfortunately, fixing a punctured radiator can be daunting and costly. It’s best to seek professional help to repair or replace it.
Answer: Cracked Heater Core
Your vehicle’s climate control system works with the heater core to warm up the cabin. It also helps to defog and defrost the windows to ensure clear visibility.
This component draws warm air from the heated coolant and circulates it in the cabin. The hot coolant will flow through the heater core to exchange heat. Note that a functional heater core doesn’t allow the coolant to come into contact with the air.
The radiator fans blow air over the heater core, and heat from the coolant warms it. Then, the heater core circulates this air in your car’s cabin. If the heater core cracks, the coolant may leak and mix with the air. As the warm air circulates in your car, you may notice a sweet aroma of the coolant.
You can fix a cracked heater core by applying sealant on the leaking part. Alternatively, bypass the heater core and drive the car to a mechanic to replace a damaged heater core.
Final Thoughts
I’ve detailed some reasons your car smells like coolant but no leak detected. Your vehicle might have a blown head gasket, cracked heater core, faulty radiator cap, or punctured radiator. If you can’t detect any leak, look for other symptoms like white smoke from the exhaust or low coolant level.
Once you determine the cause, fix it promptly to prevent further damage. Ignoring coolant leaks for an extended period can cause the engine to overheat and succumb to irreversible damage. Lastly, maintain your car’s cooling system to ensure optimal performance.