To flush or not to flush? Car fluids you should actually replace

Hey there, time traveller!
This article was published 20/02/2015 (4201 days ago), so information in it may no longer be current.

As the average Canadian vehicle owner operates his or her daily driver for a substantial amount of time and distance past a manufacturer’s warranty coverage, being able to obtain a low price guarantee on some of the most expensive-to-repair components can be an attractive offer. Here’s a look at some of the most common “recommended” services.

Transmission flush service: Servicing an automatic transmission can be done in two ways: removing the drain pan and replacing the fluid and filter, or power flushing the fluid with specialized circulation equipment and replacing the filter.

Automakers only recommend the first method even though it only removes about half of the fluid. A great deal of the transmission’s fluid will remain in the torque converter, and oil cooler and lines during a simple drain and refill process. A power flush will circulate all of the oil fluid out before pumping in new. The flush system will also remove more solid and metallic debris, thus extending the life of the clutch plate and moving components. It also prevents oil cooler or line blockage. Carmakers recommend an auto transmission fluid change between 50,000 and 100,000 km on average.

Engine cooling system service: As many of today’s vehicles are using long-life or five- to 10-year coolant, its replacement interval has been substantially extended from what it was when ordinary green antifreeze was common. As with transmission fluid replacement, there are two main methods of replacement. Power flushing an engine’s cooling system will remove more of the old fluid and debris as well as introduce a water-pump lubricant into the system. Long-life coolant service intervals are usually between 100,000 and 150,000 km for most makers. Those still using the old-style green coolant should replace it around the 70,000 km mark. Individual manufacturer intervals may differ.

Brake fluid replacement: This fluid seldom has a recommended replacement interval with carmakers. The main concern that brake fluid replacement addresses is the reduction of the water content in the fluid. With age, water is introduced into brake lines and hoses via condensation on the steel portions of the lines and the cast metal parts of the wheel brake units. This accelerates corrosion leading to fluid leaks. One hidden benefit of this process is that every bleeder screw on the system must be opened to complete it, therefore reducing the risk of them seizing with age, which could lead to the replacement of a caliper or two down the road.

Power steering fluid service: This is another fluid that carmakers consider “lifetime” with no replacement recommendation. Power steering systems are rather simple in design, with only engine bay heat and sub-zero winter temperatures to provide any extreme operating conditions. Flush treatment suppliers claim to reduce the risk of steering gear seals, pump and hose failures. Opting for a treatment supplier that provides a system warranty with purchase can help alleviate the often expensive and common repair costs of steering fluid leaks.

Fuel injection/intake service: There’s a multitude of opinions both pro and con on this service, only matched by the number of different treatment suppliers. Carmakers never recommend injector service or fuel system purges in their maintenance schedules. But many vehicles have been prone to carbon buildup on engine valves and varnish coatings on throttle plates. The two main reasons are poor fuel quality and low speed vehicle operation and stop/start driving on short trips.

Repair shops can accurately predict the demand for this service based on fuel price increases. As the cost of fuel goes up, the weight of the driver’s gas foot gets considerably lighter. When high-efficiency engines — designed to run at higher revolutions per minute — are subjected to poky driving and/or poor quality fuel, deposits will occur. A good fuel-system cleaning treatment, when properly applied, can reduce these buildups.

Whether or not you say yes or no to your service consultant’s flush recommendations depends on several things. Here are some questions to ask yourself to help you decide:

Are you planning on keeping the vehicle long enough to warrant some additional warranty coverage that certain treatment suppliers offer? Is this coverage worthwhile or cost effective? Do you have faith in your service provider’s experience and opinion? Are you a preventive-maintenance or drive-it-until-it-drops type of vehicle owner? Do you believe the improved design, engineering, and construction of today’s vehicles make them less reliant on routine maintenance in our often extreme climates and road conditions?

–Postmedia Network Inc. 2015