Today I had the oil changed and the transmission fluid topped off(it was REALLY low apparently) on my recently purchased 2001 Subaru Outback(103,000 miles) Driving home I notice a strong smell coming from my heater/defrost vent at low speed. At highway speeds I couldn’t smell it. Do I just need to let any spilled fluids burn off or is this a serious leak somewhere in the system? I have driven it a total of 15 miles after the oil change.
Did you get the oil changed at a quick lube place? These are notorious for occasionally clumsy work, and it could very well be that someone spilled something somewhere. It’s most likely nothing to worry about-- just look under your car for leaks and regularly check your fluids. If you can have an experianced nose give it a whiff, they could probably identify the smell. Or, you could get an assortment of automotive fluids (which you should keep in the car anyways) and conduct your own smell test. Engine oil, transmission fluids and antifreeze are the likely candidates, and all have very distinctive smells.
I’d be skeptical of the transmission fluid level-- that’s not a fluid that gets consumed. Unless you’ve noticed a leak, I’d double check the level yourself as per the owner’s manual. Different cars have different instructions for checking the level (hot vs. cold, engine running vs. not running, etc) and the quick lube guy may very well have had it wrong.
“Do I just need to let any spilled fluids burn off …”
This is indeed the most likely explanation, considering the recent service. Naturally you will check fluid levels and inspect for leaks but if everything checks out you may assume there was a small spill. Just let it burn off in a day or two.
As already mentioned, it probably is just spilled oil or transmission fluid burning off…however…if the smell is slightly sweet/syrupy, keep a close eye on your coolant level. Outbacks are notorious for internal and external coolant leaks. Subaru supposedly fixed this on their newer generation of cars, but a lot of people are starting to question how good this fix really was. You may have developed a leak that just coincidentally started after your oil/transmission service.