Tech tip: Fluids glossary and applications

Let us start with coolant. Coolant (formerly known as anti-freeze) does a number of things for your vehicle. It absorbs the heat generated by the engine during operation and then travels out to the radiator so it can pass the heat to the atmosphere. Then (courtesy of the water pump) returns to the engine to do the same again. In most vehicles it also passes through the heater core so you can keep warm in the winter. There are more functions of coolant most do not think about. Coolant will also lubricate the water pump. It also contains anti-rusting agents that will help eliminate rust formation inside the engine. Keeping your coolant in good working condition is important. In as little as two weeks an engine with either weak or no coolant and just water can and will form rust and will take a toll on the internal parts of the cooling system. It will also cause the soft plugs (some call them freeze plugs) to rust through and begin to leak your water to the outside of the block. No coolant or water means the engine will overheat. Keep the coolant in good condition. It is much less expensive than repairs.

Power steering fluid. It not only makes the power steering work, but it lubes the internal parts of the power steering pump and either the steering rack and pinion or steering gear, depending on what vehicle you drive. Most do not think much about power steering fluid until it leaks out of the system and you cannot steer well. It needs to be exchanged like any other fluid on the car. The fluid on many turns out to be the same fluid that is inside the automatic transmission. With that in mind you should know that it will need to be changed just like automatic transmission fluid. Not as often. If your power steering fluid is automatic transmission fluid and it is no longer red like it was when it was fresh, then that is a good indication that it should be replaced. The lubricating quality is low at that point. If your power steering pump fails internally, it is a good practice to flush all of the old fluid out of the system. It could contain metal particles that can damage the other parts including a new pump.

Coolant has nothing to do with air conditioning. These are two entirely different fluids and functions. Refrigerant is meant to cool off the inside of your vehicle for your comfort. It is not difficult to confuse these two fluids for non-automotive people. Refrigerant is different now than it was 20 years ago. R12 was used extensively in automotive applications. There was some limited use in home refrigerators too. Basically any gas that is compressed and then passes through an orifice so that the pressure suddenly drops will become much cooler as it changes from high pressure liquid to low pressure gas. R12 refrigerant was quite good at that. It has been dropped from use for a newer refrigerant called R134a. That is not really it’s name but that is the normal designation everyone uses. Like who is going to call it (R12) Dichlorodifluoromethane? Don’t think R12 is much easier? Likewise so is R134 over 1,1,1,2-Tetrafluoroethane. R12 was dropped because of the environmental issues associated with it. It was actually used in the 2^nd world war as a poisonous gas weapon. Burning it produces what is known as mustard gas. Very poisonous to breathe. Ok, enough science lessons. Each type of refrigerant has different characteristics. The air conditioning systems had to undergo some changes for them to work well. Older air conditioners in autos could be converted to the newer R134 refrigerant with some modifications. It requires some valve or port changes and uses different lube types. For some reason when an old system is upgraded to use R134, it is called retro-fitting. I always thought retro meant to go back to something. Well that is not going back. Not my call. If it was me I would call it upgrading or updating. On your older vehicles that use either refrigerant, you can switch on the a/c during the winter while using defrost or defog on the windshield and it will defog quicker. All of the newer vehicles automatically do that.

Brake fluid. Using the correct brake fluid might not seem important but it is. Always be sure to use the correct brake fluid for your car. Generally on the lid of the reservoir it will tell you which one to use. Do not mix brake fluids. If it were an emergency where you had to mix them, be sure to have the system flushed out as quickly as you can. Otherwise the rubber parts inside the system could be fatally damaged and the brakes would fail. Flushing brake system every two years is a good practice. The biggest enemy of brake fluid is water or moisture. It will naturally absorb water vapor and that will break it down. The brake system reservoir has to be vented to the outside so moisture can get in there.

As a review, fluid changes are less expensive than repairs. The cooling system, the power steering system, the automatic trans, the manual trans, the brake system and differentials, all will benefit from fluid exchanges at proper intervals. Check your owner’s manual for that interval or your technician can give you that information.