Skip the auto shop - Our mechanics make house calls

Q: What does flushing car fluids mean?

asked by on

What does flushing car fluids mean?

A: Flushing car fluids generally refers to hav...

Flushing car fluids generally refers to having a sealed systems fluid completely replaced usually with the use of a machine that is capable of complete fluid exchange. Systems that are generally flushed in our modern vehicles include the coolant system, brakes system automatic transmission, engine, power steering system, fuel injection system, and sometimes even the AC system.

This process is generally done with the use of a machine designed to remove the original fluid in the system, pass fresh fluid or a cleaner through the system and replenish the proper fluid when finished. Flushing can also be done on fuel system lines in the event of a contaminated fuel system. This helps to remove the old fluid which may have lost its lubrication or other properties and removes scale, dirt, and debris, which can affect proper operation and cause further damage. Flushing the system to remove debris would be similar in concept to clearing a partially clogged drain. Using the pressure to force the dirt and old fluids out of the system and replenishing the vital new fluid will help to ensure proper operation and extend service life. For example, coolant over time becomes acidic and corrosive and turns into an electrolyte. Along with losing the lubrication properties which help to keep seals soft and prevent rust and scale, this chemical change can cause actual engine damage to the cylinder walls, head surface, water pump or radiator. In the case of the transmission, the fluid provides the pressure needed to apply the internal clutches for gear selection and lubricates to protect from dirt and wear. Over time, due mostly to heat, these additives will break down and the fluid will lose its ability to protect the internal parts. Flushing restores the fluid and cleans the system. Think of it like a detox cleanse when starting a diet. The key to any vehicle’s long life and lower cost of overall operation is proper maintenance. Flushing should be a vital part of this process.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I have a problem in my 2004 Peugeot gear

Hi there. With the limited information about your gear box (transmission), I suggest starting with checking the fluid level and color. Make sure that the fluid is full and the color is red and not dark red or black. Then...

Q: Why must your transmition fluid be hot (warm) before yu check it?

The reason the fluid should be checked warm is due to the fluid expands as it heats up and also fluid is distributed throughout transmission. The fluid should be check when the transmission it at its operating temperature to make...

Q: How do you check the brake and clutch fluid?

Keeping an eye on the clutch and brake fluid in your car isn’t hard to do. It is important, though. Both of these systems are hydraulic, and low fluid can lead to low pressure and reduced operation. Here’s how...

Related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.