How Often Should I Change My Car’s Fluids?

The classic oil change rule of thumb was every 3,000 miles.  Some car enthusiasts will insist that you should abide by that rule, even if your new car has an alert system that detects when it is time to get your oil changed.  The truth of the matter is that everyone will have their own opinion as to when is the best time to change your oil, coolant and other important fluids in your vehicle.

Our advice?  Always consult your owner’s manual – you know, that little unopened book taking up space in your glove box – to read the manufacturer’s recommendation.

So, what exact fluids need to be replaced to keep your car running smoothly and how often should they be changed?

Lean on the experts at CNM Auto Repair for the low-down:

Motor Oil

Motor oil is a critical component to keeping your car’s engine running smoothly.  Oil lubricates your engine and helps fight against friction and heat in the car’s motor.  This helps to protect your engine from wear, which could eventually ruin your engine.  Friction and heat will degrade your oil over time; which is why it’s so important to change your oil and filter regularly.  In most vehicles, your oil should be changed every 3,000 or 5,000 miles – depending on the type of oil it takes.  Standard or synthetic blend oil should be replaced every 3,000 miles; full synthetic oil should be changed every 5,000 miles.

Transmission Fluid

Transmission fluid is a liquid that acts as a lubricant for all of the moving parts inside your transmission.  There are unique types of transmission fluid for your vehicle depending if it has an automatic or manual transmission.  It is recommended to have your transmission fluid replaced every 30,000-60,000 miles, depending on the type of vehicle you drive.  You should consult your manufacturer’s recommendation for the exact timing of when to have your vehicle’s transmission fluid changed and entrust the certified mechanics at CNM Auto Repair to do so.


Coolant helps to transfer heat and prevent engine damage caused by freezing or boiling.  Also referred to as antifreeze, coolant keeps your radiator from freezing or overheating in extreme temperatures.  Depending on the manufacturer of your automobile, coolant should be changed every 30,000-60,000 miles.  Reliable mechanics will check your antifreeze/coolant levels and top them off if necessary during routine oil changes.

Brake Fluid

Brake fluid is used to transfer force into pressure, amplifying brake force.  As we all know as drivers, effective brakes are very important!  Be sure to have your brake fluid changed every 2-3 years or 24,000-36,000 miles … whichever comes first for your vehicle.  CNM Auto Repair can help you keep your brakes in working order.

Power Steering

Since the majority of cars today have Power Assisted Steering (PAS), power steering fluid is essential for smooth steering, which allows you to turn the wheels with ease.  Power steering fluid should be replaced every 75,000-100,000 miles.

Differential Fluid 

Just because the differential is at the rear and under your vehicle, it is important to not forget about maintaining its effectiveness.  The differential is designed to compensate for the difference in distance the inner and outer wheels travel when your vehicle makes a turn.  Lubrication location and amounts depends on if your vehicle is rear-wheel or front-wheel drive.  Differential fluid, essentially “gear oil,” needs to be changed every 25,000-30,000 miles.

Transfer Case Fluid (AWD vehicles)

Transfer cases are only found on 4-wheel drive trucks, SUVs and mini vans.  It is found at the rear of these types of vehicles and transfers energy from the engine back to the rear wheels.  4-Wheel and All-Wheel Drive vehicles should have their transfer case fluid replaced every 30,000 miles to keep the small gears and moving parts lubricated and working properly.

Just as blood is essential for humans to live, oil is the lifeline of a vehicle.  It is extremely important to replace your motor oil every 3,000-5,000 miles, depending on your vehicle and driving habits.  But don’t stop at just oil changes – other fluids in your vehicle should be routinely checked and replaced throughout your car’s life.  Rely on your car’s manufacturer guidelines to determine accurate timing/mileage of fluid changes.

Here at CNM Auto Repair in Lancaster, PA, we put our customers’ minds at ease and take care of all of your car service needs.  Schedule an appointment with us today online or by phone: (717) 397-1497.  We look forward to hearing from you soon!