John Nielsen: Hi! I'm John Nielsen with AAA's Approved Auto Repair. In maintaining the fluids in our vehicles engine is important to protecting our investment in the long run.

Now fluid that we need to consider is the engine coolant, and there has been a number of changes in recent years. There are three major types of engine coolant available today, is organic, inorganic and hybrid organic. Now those terms are important, but most people refer to the type anti-freezing their car based on the color. There is the old-fashioned green, then there is yellow and red and a number of other colors in the marketplace today. It's really important to know the color, because if you need to top off your anti-freeze, you want to make sure that you're using the same type.

So if your car comes with a green anti-freeze, you want to make sure that that's what you filling it or partially filling it with. If you mix the anti-freezes you run the risk of causing damage to your engine in a relatively short period of time.

So now that we have an understanding of the basic types of coolant used in engines today, it's important to understand how to check it and when to service and maintain it. Let's consider for a moment how to check the coolant level in our engine.

Gone are the days when we'd actually check it directly in the radiator; today we're actually going to look at the coolant reservoir. The coolant reservoir is usually in the front of the engine compartment and it's going to have marks in there that tell you the minimum and maximum, in which case you want to make sure that the coolant level when the engine is cooled is between those two lines.

Now it's important to note that with these coolant reservoirs that many of them are pressurized just like the old radiators were and we cannot remove the cap when the engine is hot. It's always a great idea to look in your owner's manual to understand where to check it and if it's a pressurized system you want to make sure that you top off any fluids, check any fluids only when the engine is cool.

The final consideration is going to be engine coolant change intervals, like we've said a number of times, this is something that we want to look in the owner's manual and get the manufacturer's recommendation. It can vary anywhere from two years to five years in length. When given a range I would err on the short side, I usually change my engine coolant about every 2-3 years depending on the type of the engine, the type of driving that I do.

So engine coolant is really an important fluid to consider in maintaining the overall life of your engine. These tips are going to help you make the best choices and protect your investment for the long run.