Car Problem Diagnosis: Sweet Smell

by Geoffrey Weed
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Public Domain, Wikimedia Commons

There are so many things that can go wrong inside a car that it can often seem overwhelming. For those who know little or nothing about cars this is especially true. The important thing for people who don't know cars well is to constantly be on the lookout for symptoms that could indicate that something is wrong with their vehicle. One such symptom is a sweet smell from the exhaust or vents of the car. Such a sweet odor indicates a specific problem, one which can be caused by several different occurrences.


In the vast majority of cases, a strongly sweet smell coming from a car indicates that the car is suffering from a coolant (also sometimes called antifreeze) leak. The odor itself can vary somewhat. Some people describe it as smelling somewhat like maple syrup while others associate it more closely with butterscotch. Others claim that it smells like sweet cinnamon. In any case, regardless of nuances, the sweet smell generally indicates that coolant is leaking somewhere in the vehicle's engine.


The reason for the sweet odor is the fact that automotive coolant has a decidedly sweet smell and taste. This is why it's so important to keep coolant away from pets and children. Its sweet aroma can entice animals and sometimes even people into tasting it. Sadly, its sweet taste may provoke them to drink even more. Coolant, however, is toxic and can kill in high enough doses.


A leak in your car's coolant system can cause serious problems. The worst potential outcome is catastrophic engine failure due to overheating. If you detect an unexplained sweet smell coming from your car, it's of extreme importance that you treat the underlying problem as soon as possible. Within even a short period of time an engine that is running without adequate coolant can overheat and seize.


Unfortunately, there are many potential sources of coolant leakage located throughout most car engines. If you think that you have a coolant leak, and you aren't a certified mechanic, your best bet is to take your car in for immediate service. Automotive professionals will be able to locate the source of the leak and, in most cases, fix it relatively inexpensively. If you wait too long and the leak causes engine damage from overheating, the costs can be astronomical and the damage could actually total an older vehicle.


Potential financial concerns and damage to your car are not the only reasons to treat a sweet smell. As mentioned earlier, automotive coolant is extremely toxic. It contains a large amount of a poisonous chemical called ethylene glycol. A dose of roughly 0.1 ml of ethylene glycol per kilogram of body weight is considered deadly in humans. While it is unlikely that a person could ingest this amount via vaporized coolant from a leak, it is potentially possible. Also, leaked coolant can be found by animals or children and ingested. This is another reason that it is important to treat that sweet smell quickly and stop the leak from getting worse.

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