I bought the 15L unit, thinking I could clean car parts such as brackets, pulleys, carburetors, and things of that size. It showed up sooner than I expected, and was packaged well. It looked nice coming out of the box, and I was excited to try it out! The first thing I tried was an engine pulley that was caked with dirt and grease. I used a degreaser that was flammable, so I left the heat off. It did an ok job. I ran it three times (30 minutes each), but the pulley was still pretty dirty. After that, I used the heater and tried spraying some Dawn Power wash in there, but that didn't do a whole lot. I think it was too diluted, frankly. The best results I have had so far were with the heat cranked up as far as it went (80° C), and 7 cups of Simple Green (about a 4:1 ratio). I ran that same pulley once, some bolts coated in grease, and a couple of brackets. I ran it 4 times for 30 minutes each, and it removed probably 90% of the gunk. My overall thoughts are: It is a little noisy. Not bad, but louder than I expected. It holds about 3 gallons. It took 3 hours (yes, you read that right) to fully heat up, and I wish it got hotter. This unit is ok. I would probably buy something else more heavy duty for completely caked engine parts like what I tried, if you can. I am going to finish cleaning these parts by hand. I like using it. I don't do well with fumes from brake clean or heavy degreaser, so this is better in that regard since I can just walk away. However, if you are in a time crunch, you will be better off with some degreaser, a scraper, and a wire wheel, or a parts cleaner. I attached before and after photos and a video of it running.