It is often difficult to know for sure how long your oil might last before it needs a change. The type of car you drive, the size of the engine, the age of the engine, the type of driving you do and the type of oil that is in your crankcase will ALL have a significant effect on the longevity of the oil. .
Of course, quick lubricants will continue to tell you that 3,000 mile changes are a necessity, and, for SOME people, that may be true. However, for the vast majority of us this has not been necessary for many years. Unfortunately, determining HOW LONG is OK can be difficult.
Entering Oil Analysis
The best way to establish realistic oil change intervals is to analyze the oil. Those who have been professionally trained to test oil and have expensive laboratory equipment are probably the most qualified to determine the quality of the used oil in your vehicle.
Such a thorough analysis of your oil, however, can be prohibitively expensive, as a professional oil analysis can often cost as much as a 5 liter oil change.
The result – we don’t
Of course, the result is that most people won’t pay for a “real” oil test – but they might be willing to do a simple oil test on their own, if they knew how to do it. It won’t give you detailed numbers like you would in a lab, but it can give you a pretty good idea of how your oil is holding up, helping you decide whether it’s time to make a change or not.
Below are detailed instructions for one of 6 layman’s oil analysis tests that you can use to determine how well your oil is holding and whether it is ready for a change. This way you can start to set realistic oil change intervals for your vehicle.
Running the test
Using this simple layman oil analysis test can shed light on a wide range of potential oil problems that might require an oil change: excessive particles, build-up of condensation, glycol contamination, fuel dilution, dispersant additive failure, sludge formation and product oxidation. This is probably one of the most useful DIY oil analysis tests you can perform, and it is very straightforward.
While your engine (and oil) is HOT (not HOT), let a drop of oil fall from your dipstick onto a thick, white, NOT shiny business card. Lay the paper or business card flat, but so that all edges of the paper are hanging. As a possible example, if you’re using stiff card stock or a stiff business card (which you really should be), simply place the card on top of a mug or mug of some kind.
You want to wait for the paper or card to completely absorb the oil drop, which may take a while. The list of characteristics below should help you assess the condition of your oil based on the DRY oil stain.
- If your oil is still good for continued use, the dry oil stain will be a uniform color with no particularly dark areas or dark circles. There may be a slightly yellow outer ring.
- If your dispersant additives fail, you will likely see a very dense and quite dark area, normally in the center of the circle. Remember to change your oil quickly, especially if other problems arise during “testing”.
- Glycol (antifreeze) in your oil? Expect to see a very black and somewhat “mushy” area within the oil stain. Change your oil very soon.
- If the circle is really dark and has a very distinct outer ring, your oil is badly oxidized and should be changed immediately.
- If the center of the circle is dark enough and there are outer rings, you can probably have fuel in your oil. This does not necessarily mean that you need to change your oil since it is common to have fuel in your oil, but it could if the level is too high. Only a professional analysis will tell you how high these levels are.