What are some common locations for oil leaks on a Smart 451?

Question

The Car

I have a 2010 Smart ForTwo with just under 100k miles. It's a Model 451 with a 1.3L engine.

The Problem

The car is losing oil. There are no spots on the ground when I move the car, but the oil level drops consistently over time (maybe a quart per month/2000 miles or so). The exhaust doesn't smoke nor does it smell like burning oil. There is a dirty, wettish spot on the differential housing just in front of the driver-side axle, but...

Troubleshooting

The most recent time I changed the oil I added some oil-based UV Fluorescent Dye. I've used it in the past to good results, but this time I haven't seen any bright glowing leaks anywhere when I inspect under the car with a UV light. Notably, the wet spot on the differential does not have any dye, so either it's an old leak which still hasn't dried (seems unlikely) or the dye isn't leaking yet. I tested the dye before I filled the engine and it definitely glowed properly under a black light.

The Question

Are there any common locations oil tends to leak on these cars? Is there a way oil could be leaking in such a way to pool onto the differential housing? More importantly, are there any locations which aren't easily seen from beneath (maybe a leak onto another surface, for example)? Is it possible the engine is burning that much oil without smoking?

Answer 1

Is it possible the engine is burning that much oil without smoking? Absolutely! Every car ever made will begin to "consume" oil, without obvious burning, as it ages.

How to fix:

1. Flush the crankcase with BG EPR. Change the oil immediately.
2. While replacing the oil, add Engine Restore.
3. Add ATP Re-Seal to the engine oil as well, 1/2 oz. per quart.

Allow the additives to work for 3,000 miles. Problem solved! Re-apply the Restore with any oil change if you feel you want a boost, but use the Re-Seal only once.