Where is the problem when you smell coolant in the engine compartment?
3 Answers
The reasons for smelling coolant in the engine compartment are as follows: The coolant has not been replaced for a long time. The service life of ordinary coolant is generally 3 years, while long-life coolant lasts only about six years. Not replacing it for a long time may cause the corrosion inhibitor in the coolant to lose its effectiveness, leading to changes in the composition ratio, which results in an odor from the coolant. Coolant overflow or leakage. When it encounters the high-temperature engine and drips onto the engine block or exhaust manifold, the coolant boils and evaporates, producing an odor. How to determine if there is a lack of coolant: Observe the coolant warning light on the dashboard. If it lights up, it is likely due to a lack of coolant, although it could also be caused by excessively high cylinder temperature. Check the coolant reservoir. If the liquid level is below the minimum mark (MIN), do not continue driving and add coolant promptly. Check the water level scale mark on the coolant tank. The normal coolant level should be between the maximum and minimum water levels. Whether there is a lack of coolant depends on the scale. If the coolant is below the minimum water level, it indicates a lack of coolant.
Last time my car also emitted that sweet antifreeze smell, and it turned out to be a deteriorated radiator. Antifreeze mainly circulates in the water cooling system, and leaks usually occur in just a few spots: Radiator edge seepage is most common, as plastic parts and metal interfaces deform over time; the heater hose connection behind the dashboard, if leaking, will release a particularly noticeable odor through the AC vents; and if the water pump seal wears out, you can spot pinkish crystals around the pump body when opening the hood. The most troublesome issue is a blown head gasket, where antifreeze mixes with engine oil—checking the oil cap will reveal milky foam. If you smell this on the road, it's best to stop and inspect immediately, as high-pressure, high-temperature antifreeze spray is no joke.
Ah, I ran into this issue last year! That sweet syrup smell of coolant is so distinctive. Focus on these key areas: First, check if the rubber hoses at the radiator's upper and lower pipe connections are damp—older cars often have loose hose clamps. Then inspect the filler cap; a cracked seal can also leak vapor. For turbocharged cars, take a look at the intercooler connecting pipes—my friend’s car once had a tiny hole there from a rock impact. If you notice white smoke with a sweet smell from the exhaust when starting a cold engine, get the cylinder head gasket checked ASAP—it’s likely leaking into the combustion chamber. And remember, never open the radiator cap directly when the engine is hot—high-temperature steam can scald your hands!
