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" Hot Clutch WoesQ: I have a 1995 Celica ST Liftback with 245,000 miles on it. It has been having transmission problems (or at least I think it&amp;#039;s the transmission) for about the last year. After long interstate drives (say 45 miles) at 75 mph, the clutch pedal becomes very &amp;quot;spongy.&amp;quot; It engages near the bottom of the throw, close to the floor, but most of the time I can still shift gears. Once I exit the highway and drive at normal speeds (say 35-50 mph), the clutch pedal operation returns to normal after a short period of time. The symptoms seem to be limited to the heat of the summer and were not noticeable over the past winter. There was one instance on the interstate where the clutch pedal was unresponsive and would not engage when pushed to the floor, making me unable to shift gears. I had to pull off the road, shut the engine off, and let it cool. After about 15 minutes, I restarted the engine and there was just enough of the clutch pedal to shift gears. I then got back on the interstate, reduced my speed, and normal clutch operation returned. A local garage misdiagnosed the problem last year and replaced the clutch, so I have a new clutch but the problem still persists. Any ideas? A: Sounds like the slave cylinder is overheating and boiling the hydraulic fluid. I&amp;#039;d start by flushing and bleeding the clutch hydraulic system. But I wonder why it&amp;#039;s overheating. It could be a throwout bearing that&amp;#039;s spinning and getting hot, because the slave cylinder is misadjusted. Or, the exhaust system is routed right nearby and radiating heat onto the slave or the hydraulic line. At 245,000 miles, you were due for a clutch, even if it was still working. Too bad they didn&amp;#039;t catch the real problem. Overfilling Engine Oil Q: I bought a 2007 Toyota Prius a couple of months ago. Because of its technology, I started looking for information about it on the Internet. To my dismay I discovered that dealers seem to have a tendency to add more motor oil to it, in routine service, than Toyota specifies. According to what I have read, the engine is supposed to hold 3.9 quarts. However, according to Prius users, 3.5 quarts will bring it up to the full line, and the dealers are actually putting in 4.0 quarts, raising the level anywhere from 1/8&amp;quot; to 1/4&amp;quot; over the full mark. Is this a real problem for the Prius if it is overfilled by the indicated amounts? A: A slight overfill isn&amp;#039;t that big a deal. Any more than about a half-quart stands the chance of frothing, oil pumped into the engine through the PCV system, and leaky seals. Canister Oil FiltersQ: I have mostly seen cars with spin-on type oil filters. Currently, I have a 2005 Chevy Cobalt with the 2.2 liter engine, and it has an oil canister/cartridge setup attached with two long bolts. Could you explain the pros and cons of this system, versus a spin-on filter? A: There&amp;#039;s an industry trend to canister- or cartridge-style filters, because the spin-on type are too hard to dispose of properly. They have to be crushed or cut open to remove as much oil as possible. Canister cartridges just need to be drained. It really makes no difference to your engine. A side benefit of the canister is the ability to remove the filter canister without having to struggle with a stuck spin-on filter. Gas Savers: Too Good to be True?Q: I recently watched a news clip about the Aqua Tune Hydrogen modification to a car engine, and was impressed with the results. The clip also mentioned that Popular Mechanics has reviewed some of these &amp;quot;mileage-increasing&amp;quot; techno gizmos, and I wonder whether you can direct me to your reviews on your website, since I can&amp;#039;t seem to find anything about this. By the way, they also claim that your installation was &amp;quot;bound to fail&amp;quot; (of course) and I&amp;#039;m wondering if you have received any positive feedback regarding this system? A: For a review of my tests, click here. You can also find these by searching our website for &amp;quot;Fuel Saver.&amp;quot; &amp;quot;Bound to fail&amp;quot; as a result of following their instructions? Whatever. I haven&amp;#039;t heard from many readers who have installed the Aqua Tune system, good, bad or otherwise. Any time gas prices spike, this whole field of gadgets comes up again. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/cars/how-to/a1822/4218788/>