* Water pump leak: A common culprit. The water pump is located at the front of the engine but a leak might drip down and back, explaining the location of the antifreeze on the garage floor. A failing water pump seal can leak internally or externally.
* Hose leak: A small crack or hole in a hose, particularly one running near the back of the engine, might only leak when under pressure (while driving). These are difficult to spot sometimes.
* Cracked engine block or head gasket: This is a more serious issue. A crack in the engine block or a blown head gasket can allow coolant to seep into the engine, sometimes burning off (causing the smell) and sometimes leaking externally depending on the location of the crack or gasket failure. This is less likely if the leak is small and only occurs intermittently.
* Heater core leak: The heater core is located inside the passenger compartment. A leak here could lead to the antifreeze smell in the cabin, and *some* might leak externally (though less likely to get to the garage floor in the back).
* Transmission cooler leak (if integrated into radiator): The Astro van's transmission cooler is often part of the radiator assembly. A leak in this area can mix transmission fluid and coolant, leading to a sweet smell similar to antifreeze (though often with a burning smell as well).
What to do:
1. Thorough visual inspection: Carefully examine all hoses, clamps, and the water pump for any signs of leaks, cracks, or corrosion. Look for discoloration or staining around potential leak points. Pay close attention to the area near the back of the engine, where you're seeing the drips.
2. Pressure test the cooling system: A mechanic can perform a pressure test on your cooling system. This helps pinpoint the leak by pressurizing the system and observing where the pressure drops.
3. Inspect the engine oil: If there's a head gasket leak, coolant can enter the engine oil, making it look milky or brownish. Check the oil dipstick for any unusual color or consistency.
4. Check the coolant level regularly: Monitor the coolant reservoir to see if the level is dropping, even slightly.
Important: Driving with a low coolant level can lead to engine overheating and serious damage. Do not continue driving the van if the leak is suspected to be significant. Get it checked by a mechanic as soon as possible to diagnose and repair the issue. A small, intermittent leak might become a major problem quickly.
