Was thinking about using this before my next oil change, car only has 36k miles on it, but I don't really know how well it was taken care of by the previous owner. Does anyone have any experience with this product, or any Liqui Molly products for that matter?

 

Just warm the car up and drain the oil then be sure to put some good synthetic in it as required. I don't think that additive stuff does a whole lot except cost you more money. If you are concerned, change the oil and filter, drive it for 1000 miles and change it again. I changed out my drain plug for a magnetic one so I'll see what I get on that the next change on mine.

 

I've used the generic "oil cleaner" solvents on used cars I've purchased before.
It works IF the engine oil is extremely thick / sludged / chunky.
If the existing oil flows with ease and there's little to no 'curds', then it's not necessary.
As stated above, warm the engine to running temp, drain the oil / change filter, and install your favorite brand synthetic oil.

- Erik