Under The Hood
Under The Hood: Opinions Differ On Changing Fluid
Published: Thursday, May 17, 2012 at 10:11 p.m.
Last Modified: Thursday, May 17, 2012 at 10:11 p.m.
Q: I'm due for an automatic transmission fluid change for an '04 Accord V6 with 126,218 miles on it. The owner's manual recommends draining and filling the ATF Z1 four times, driving and moving the car through all gears between each drain and fill. I've contacted three mechanics, who all gave different information. Which procedure is correct, and why?
A: Opening the drain plug of your automatic transmission allows only about 40 percent (3.1 quart) of the fluid to escape. The remaining fluid is trapped in the torque converter and a multitude of internal places and passages. This makes a great case for draining/refilling several times (and running the transmission through its paces between) in order to turn the tide on the old fluid. The more times one repeats the process, the smaller the percentage of old fluid remains.
Honda has come out with a new ATF DW-1 fluid that offers improved cold transmission performance and improved fuel economy, compared to the original ATF-Z which has been discontinued.
Q: How can you tell when your battery terminals need cleaning? I've had or seen a few cars that had horribly dirty-looking terminals but there seemed to be no problems caused by it. And then there was the time my car wouldn't start and the clean-looking terminals turned out to be what caused it.
A: A corroded battery terminal can lead to starting problems, odd computer glitches, and even radio static. A simple voltage drop test will tell you the real story about terminal performance. You'll need a basic multimeter (Sears Craftsman ? 82139 is a favorite at about $30) and a helper.
With the meter set to volts DC, press/hold the red lead tip against the battery positive post and the black lead to the cable clamp (only a half inch or so apart). Watch closely as your helper cranks the starter — keep hands and leads clear of moving parts! A reading of .2 volts or less indicates an acceptably small amount of voltage drop across the connection during the most severe service the terminal connection will ever see. If the engine starts too quickly to see the reading clearly, press the data hold button.
Next, check the negative terminal in the same way, this time black lead to post and red to clamp. This quick test unfortunately can't be performed on side terminal batteries as the cable end obscures access to the battery terminal.
A reading above .2 volts indicates terminal cleaning is needed.
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