The article shown below will describe for you one of six incredibly valuable used oil tests you can use to quickly establish the continued viability of your oil, without ever paying a single dime to an oil analysis lab.

If you are one of the many people who owns a vehicle that is driven infrequently, is commonly driven on low mileage trips and/or is driven or stored in a humid climate or one that often has wide temperature swings, then the performance of a crackle test would likely prove useful. This is a simple DIY test which will tell you if condensation is causing water build-up in your oil.

Why test for water ingression? Because water build-up leads to acid build-up. Acid causes corrosion which leads to pitting. Of course, you don't want pitting inside your vehicle's engine. Even a high TBN extended drain synthetic oil like AMSOIL can eventually be overcome by water/acid build-up. So, it stands to reason that you'd want to know if you were getting water in your oil BEFORE acid build-up depletes your oil's acid fighting ability. THIS is why I recommend performing the crackle test.

However, if performing the blotter spot test prior to the crackle test shows that there is fuel in your oil, performing the crackle test will likely be of little use, since the fuel in your oil will "throw off" your results. This is why the blotter spot test (business card test) is most often performed PRIOR TO the crackle test. If there's fuel in your oil, you may already need an oil change, and the results of the crackle test will not be clear anyway.

To perform the crackle test, you simply place a small quantity of oil onto a hotplate of some sort which is set to a temperature high enough to boil off any water in the oil. Since most engine oils are not volatile until they gets up around 375 degrees F or higher (synthetics much higher than that), you could set the plate to a temp anywhere between 250 and 300 degrees F.

At that temp, when you place the motor oil on the plate, you will hear a crackle as the water boils off. The crackling should occur very quickly as long as the amount of oil you use is small. Of course, if you have no water in your oil, you will hear no crackle.

Of course, the crackle test is not a very accurate test, and it will not tell you how much water you've got in your oil, as a professional oil analysis will, but, it can still provide you with some useful, cheap info.