Noticing any unusual smell in your vehicle can be disconcerting, as you know there may be something off in your powertrain. One of these common odors you may experience is a sweet smell, similar to burning marshmallows. While that may sound like your car is just cooking up a campfire treat, this source of this smell is actually a failure in one of the most important systems in your vehicle.
In this article, we’ll go over the main causes of a sweet smell and what it could mean for your vehicle.
Where Is That Smell Coming From?
If you notice a suspiciously sweet odor from your car, it’s likely the smell of burning coolant. Automotive coolant, or antifreeze, contains ethylene glycol, which is the primary reason for the sweet odor as the coolant burns off.
Coolant burning can occur in a variety of different places within your cooling system, as any leak in the coolant lines can allow for coolant to drip onto hot engine components, instantly burning it off and releasing the smell in question.
Common Coolant Leak Locations
While the exact location of a leak can be difficult to pinpoint, there are some more frequent areas to keep an eye on.
Blown Head Gasket
The head gasket acts as a seal between the engine block and cylinder head, ensuring that oil and coolant are not able to enter the combustion chamber.
Over time, due to high heat or wear, the gasket material will degrade and can reach the point of allowing coolant to leak into the combustion chamber. This internal leakage causes the coolant to burn off as the air-fuel mix is ignited, producing a sweet odor of burning coolant that emanates from your tailpipe.
Head gasket issues are nothing to let linger, as not only can an internal leak cost you crucial coolant volume, it can disrupt the operation of the engine and prevent proper combustion, leading to inefficiency, performance issues, further damage, and even irreparable failures of the engine itself.
Coolant Lines
Coolant lines run throughout the engine bay and carry the necessary amount of coolant to each part of the powertrain. When these lines experience damage or excess wear, it may allow for coolant to leak. While this doesn’t inherently cause coolant burn, since it’s leaking externally rather than into the combustion chamber, it’s possible for these leaks to occur over hot engine components. When the coolant leaks from the lines and drips onto these components, it burns off and causes a similar smell to an internal leak.
However, unlike an internal leak, external coolant leaks generally do not have the same severity as a blown head gasket. While coolant leaks can still cause you to lack adequate fluid for proper cooling, as long as the coolant is regularly topped off, it will typically not cause harm to the other parts of the powertrain.
Heater Core Leak
Your vehicle’s heating system relies on the excess heat absorbed by the coolant to produce that warm flow of air needed to heat your interior. Like any coolant-related component, it’s possible for corrosion and damage to cause leaks that allow coolant to exit the system. Neglected and contaminated coolant can also become acidic and cause further corrosion to the heater core and other components.
With this leak occurring so close to the heater core and inlet into the climate control vents, the smell of burning coolant may become noticeable in your cabin. This can also result in a thin layer of sticky coolant residue building up on the windows and other interior surfaces. If you notice a strong coolant smell in your interior, you should have your vehicle inspected by a trusted professional as soon as possible to prevent you and your passengers from inhaling dangerous coolant fumes as well as further damage to your heater system.
Cooling System Maintenance & Repair in Portland, OR
If you notice a sweet odor coming from your vehicle, or are experiencing any other cooling system-related issues, don’t hesitate to reach out to the experts at Stellar Auto Repair in Portland, OR. Our team has extensive experience in providing high-quality cooling system diagnostics, maintenance, and repair no matter the make or model.
Give us a call or schedule online today to secure your appointment with the premier cooling system service facility in the Portland area!
