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Flushing Out the Myths: When to Flush Your Cars Fluids and When to Pass

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Flushing Out the Myths: When to Flush Your Cars Fluids and When to Pass

Busting the Myth of Mandatory Fluid Flushes

As a self-proclaimed car enthusiast, I’ve heard my fair share of automotive myths and misconceptions over the years. But one that really grinds my gears is the notion that you have to flush your car’s fluids every X number of miles or years. Seriously, where do these ideas even come from?

If I had a dollar for every time someone told me I needed to flush my transmission, power steering, or coolant, I’d be rolling in the dough by now. Don’t get me wrong, fluid flushes can be important maintenance tasks – but they’re certainly not one-size-fits-all. In fact, performing unnecessary flushes can actually do more harm than good in some cases.

When Flushing Makes Sense (And When It Doesn’t)

Now, I know what you’re probably thinking – “But doesn’t my owner’s manual say to flush the fluids every 30,000 miles or 3 years?” Well, yes and no. While those recommendations often appear in manuals, they’re really just general guidelines. The reality is that your individual driving conditions, fluid condition, and vehicle make/model should all factor into when (or if) a flush is truly warranted.

Let’s take a closer look at some common automotive fluids and when you might want to consider a flush:

Transmission Fluid

Ah, the ol’ transmission fluid flush. This is probably one of the most debated maintenance tasks out there. Some shops will tell you to flush it every 30,000 miles, while others say it’s fine to go 100,000 miles or more.

Here’s the thing – modern transmissions are designed to go the distance without needing frequent fluid changes. If your transmission is shifting smoothly and there are no signs of trouble (like slipping, grinding, or leaks), you can probably skip the flush and just change the fluid per the manufacturer’s recommendations.

However, if you tow heavy loads, do a lot of stop-and-go city driving, or simply want peace of mind, a transmission flush every 50,000-75,000 miles isn’t a bad idea. Just be sure to use the exact fluid type specified for your vehicle.

Engine Oil

This one’s a no-brainer – you should be changing your engine oil and filter on schedule, period. Most automakers recommend an oil change every 5,000-10,000 miles, depending on your driving conditions and oil type.

But what about flushing the oil system? Well, unless you’ve seriously neglected oil changes over the years, an oil flush is usually unnecessary. The act of changing the oil and filter is generally sufficient to keep things clean and running smoothly.

That said, if you’ve gone way too long between changes or notice a substantial sludge buildup, an oil flush might be worth considering. Just be sure to use a high-quality flush product and follow the instructions carefully.


Coolant is another fluid that often gets the “mandatory flush” treatment, but the reality is a bit more nuanced. Most automakers recommend flushing and replacing the coolant every 30,000-60,000 miles, depending on the type of coolant used.

The key thing to remember is that not all coolants are created equal. Traditional green or yellow coolants typically need to be flushed more often than the newer, longer-lasting “extended life” coolants. These can often go 100,000 miles or more before needing a full flush.

As with transmission fluid, the condition of your coolant is the real deciding factor. If it’s looking dirty, contaminated, or past its service life, a flush is probably a good idea. But if it’s still in good shape, you can likely just top it off as needed.

Power Steering Fluid

Power steering fluid is another one that gets flushed maybe a bit too frequently. Unless your steering is feeling noticeably heavy or you’ve noticed any leaks, a power steering flush is usually unnecessary.

Most automakers recommend changing the power steering fluid every 60,000-100,000 miles, depending on the vehicle. And even then, a simple fluid change (without a full flush) is often sufficient to keep things running smoothly.

The only time I’d really consider a power steering flush is if you’ve had a major repair done, like a rack and pinion replacement. Otherwise, just keep an eye on the fluid level and condition, and change it per the manufacturer’s interval.

The Bottom Line on Automotive Fluid Flushes

At the end of the day, the key is to not get too caught up in the “mandatory flush” myth. While regular fluid changes are important, a full-blown flush isn’t always necessary – and in some cases, can even do more harm than good.

Instead, focus on keeping a close eye on your vehicle’s vital fluids. Check them regularly, look for any signs of contamination or degradation, and follow the maintenance schedule outlined in your owner’s manual. If something seems off, that’s when you should consider a flush.

But don’t feel like you have to flush every fluid every X number of miles. Trust your senses, do your research, and work with a reputable mechanic who can give you honest advice. Your wallet (and your car) will thank you.

So the next time some self-proclaimed “auto expert” tells you that you have to flush your transmission, coolant, or power steering, feel free to give them a friendly eye roll. Because when it comes to automotive maintenance, one size definitely does not fit all.

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