Looks like I dug up an old thread, but my issue is on topic.
Last week and about 50 miles ago I added distilled water to my coolant reservoir tank, which was just below the 'add/low' mark. Today while I was out running errands I noticed a whiff of antifreeze, but it typically has done that in the past after shutting it down after a drive, but no leaks ever found. Today the smell was much stronger.
After I arrived home, I found a large puddle on the garage floor, a mix of motor oil and orange antifreeze. Nothing visible topside while looking with a bright LED flashlight so I put it up on the lift and pulled the underbelly cover to see what I could find.
There are signs of residual wetness, both antifreeze and oil on the belly pan towards the right rear, which smells like antifreeze, and oil slinging from the large pulley on the bottom right of the engine, slinging all around from leaking while running. Not enough to get the accessory belt wet. The insulation around the oil pan is dry inside. There are no apparent coolant leaks anywhere, no wetness visible from the top or bottom.
Could the water pump be leaking both oil and antifreeze? Maybe I caught this early enough, as I have yet to see the 'low coolant' light come on, as I typically check under the hood often for fluid levels and potential leaks. Definitely no coolant leaking from around the plastic oil filter housing area, which I've found threads here stating that has been a rare cause to others.
I will be taking it in asap to get checked out, as I don't have a way to pressurize the cooling system myself. Or the tools and time to do a water pump change.
Thankfully I have an extended warranty that's still good for a couple years and several thousand miles. I bought my Passat Certified Pre-Owned with 37K miles and paid for the extended warranty.