Without trying to toot my own horn, I know a lot about cars. I understand how most items on a car function and how they fail. I know the difference between a 6 ply tire and a bias-ply tire; I can talk about the pros and cons of direct injection; I can argue in favor or against anti-lock braking systems, etc.
This knowledge frequently causes frustration when I take my vehicle in for basic services like an LOF (lube, oil, and filter), tire rotations, etc. and I’m “pitched” an unnecessary service item. While I know the service being pitched is a giant waste of money, the average consumer probably doesn’t know…and that makes me angry. Service professionals who recommend unnecessary services ought to have more respect for the consumer (and better ethics).
As a general rule, fluid flushes and/or replacements are unnecessary. Here’s a list of maintenance items that involve a fluid flush/replacement and guidance on whether or not to pay for each.
Power Steering Fluid Flush – These are rarely – if ever – necessary. Power steering fluid will become dirty and smelly over time, but it will remain functional for the life of most vehicles. Unless your vehicle manufacturer recommends changing this fluid (and very few of them do), or your power steering system is giving you trouble, there’s simply no reason to bother with a power steering fluid flush.
Brake Fluid Flush – Brake fluid is hydrophillic, which means it sucks up water like a thirsty camel. Brake fluid can even pull water out of the humidity in the air. As brake fluid sucks up moisture, it loses effectiveness. If it absorbs enough water, brake fluid can even “boil over” during normal use.
In light of brake fluid’s sensitivity to water, automakers go to great lengths to ensure your brake system is completely and totally sealed. Therefore, the average vehicle never needs replacement brake fluid. Unless you’re doing a LOT of heavy braking (racing, towing a heavy trailer on a regular basis, etc.), your brake fluid will last as long as the system remains sealed. It’s almost always unnecessary to flush brake fluid.
Coolant Flush – Many vehicles use long-life engine coolant, which has a typical life expectancy of 150k miles. Some still use “conventional” coolant, which only has a 30k mile life expectancy.
To determine if your car needs coolant flushes every 30k miles or every 150k miles, check your vehicle manufacturer’s scheduled maintenance booklet. Follow the interval suggested – no more and no less.
Automatic Transmission Service/Flush – Last but not least, automatic transmission services are often completely unnecessary. Most new vehicles use synthetic transmission fluid that can last the lifetime of the vehicle – meaning that you’ll never, ever, EVER have to change it. Just check your vehicle’s maintenance booklet…if you don’t see a recommended transmission service interval, than your transmission doesn’t need service.
NOTE: Another clue that your transmission doesn’t need service? There’s no transmission fluid dipstick under the hood. Most automatic transmissions with lifetime fluid are “sealed,” meaning there’s no way to change the fluid.
When I’m told by my local shop that my transmission needs flushed, and I reply that the transmission uses a lifetime fluid, the person I’m talking to will often tell me that replacing my transmission fluid “couldn’t hurt.” This is completely and totally incorrect. Replacing the fluid on a transmission that doesn’t require fluid replacement is a delicate procedure. If it’s done incorrectly, damage is likely.
If you take nothing else from this article, remember this: Unnecessary transmission service can cause transmission failure.
Beware “Power” Flushes – For a time, “power” fluid flushes were popular. The thinking was that forcing fluid through your vehicle’s transmission, cooling system, etc. would be more beneficial than simply draining and replacing fluid.
Unfortunately, it took a while for auto service professionals to recognize that “power” flushes often do more harm than good. Power fluid flushes have caused leaks in cooling, steering, and braking systems, and they’ve ruined thousands of automatic transmissions.
If your local shop wants to “power flush” something, find another place to get your service done. Power flushing is unnecessary, and in many cases it can cause a failure.
*NOTE: I realize that some of you might argue that a true enthusiast changes their own oil, rotates their own tires, etc. Maybe so. I’ve learned that it takes me longer (and therefore costs me more money) to do these things myself. I’m also lazy.
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