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Over the weekend I took my 2000 Toyota 4Runner to a local shop to get the oil changed. While there they told me I needed to flush the coolant, pulling clear water out of the coolant reservoir. They insisted that the water in the coolant could cause problems for my engine. Also insisting that I couldn't flush it myself because it requires special equipment.

Given that I know antifreeze is in the engine and it was last serviced by the dealer I'm a little perplexed as to how water (or a clear liquid anyway) ended up in the overflow.

My guess is that coolant is low, so the overflow was empty. They added water so they could up-sell me into flushing the coolant system.

Is there any other reasonable explanation for how that could have happened?

(for the record I didn't have them flush the coolant)

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3 Answers 3

up vote 2 down vote accepted

Since it's clear the shop was being dishonest, I wouldn't even assume the overflow tank was low. They could have just poured it out or siphoned it off and filled it with water.

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To add to R...'s answer, I don't know about your Toyota, but on my buick there's a wingnut on the radiator, once I unscrewed that all the coolant came out (so drip pan was my 'special equipment'), once it stopped I tightened the wingnut and added properly mixed coolant, been running fine ever since.

If you really want a peak at what it will take, here is the repair manual for your car, and this site is offering a download of it, I don't know how legit the download is, but Haynes manuals are pretty accurate from my use.

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In fairness, you can't do a real flush without a little bit more equipment; up to half of the coolant will remain in the system depending on your vehicle if you just drain it from the bottom of the radiator. The best method of flushing seems to be to disconnect bottom radiator hose at the thermostat and run water from a garden hose or similar backwards through the radiator, coming out at the thermostat housing. –  R.. Apr 30 '13 at 16:01
@R.. I think I've heard that before (along the lines of run water into it until it comes out clear), thanks for the info, I probably need to flush mine and will keep that in mind. –  BigHomie Apr 30 '13 at 16:29

The only special equipment you'll need to flush your own radiator is a bucket. The fact that they claimed it would take special equipment is just one red flag. I'd be skeptical they even changed the oil. Just google how to flush your Toyota's radiator, you'll see it's super easy. And see if you can warn everyone else in your area about that shop.

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I disagree. The power flushers that shops use do a much better job than DIY with a bucket. :-) –  Brian Knoblauch May 1 '13 at 17:45

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