Dear Tom and Ray:
In a previous column, you referred to "de-carbonizing" an engine. What is "de-carbonization?" - EleanorRAY: De-carbonization is what happens when you leave the cap off the ginger-ale bottle over night, Eleanor.
TOM: Actually Eleanor, it's a very good question. If your engine ran perfectly - we mean politically, socially and environmentally - then it would produce nothing but carbon dioxide and water.
RAY: But cars don't run perfectly. And one of the by-products of the incomplete combustion is carbon - otherwise known as soot. And in the engine, this soot can build up and eventually keep the valves from closing all the way. It's kind of like having your foot stuck in your mouth when you're trying to close it all the way. My brother knows all about that.
TOM: So de-carbonization is simply the process of getting rid of that carbon. Back in the old days, mechanics would actually take engines apart to clean out the carbon. But unless it's an extreme case, there are easier ways to do it now.
RAY: First of all, just driving the car at highway speed on a somewhat regular basis should keep the carbon from building up in the first place. But if it does build up, try one of the fuel additives. We've had pretty good luck with Chevron's Techron and B & G Industries' 44K.
Dear Tom and Ray:
You two dispense a lot of hot air. What is your opinion about using nitrogen instead of air in the tires of personal vehicles? - Bob
TOM: Well, Bob, I can tell you're a card-carrying member of the Nitrogen Users Technical Society (NUTS). And we want you to know we support you in your efforts to promote the increased use of nitrogen.
RAY: In fact, we've been encouraging all of our readers to wear small tanks of nitrogen on their belt loops. I mean, you never know when it could come in handy. You might suddenly find yourself in an oxygen-rich environment, and if you have your personal nitrogen, you'll be prepared to take action and dilute it.
TOM: Actually, Bob, if you really want to get technical, there are a couple of advantages to nitrogen. First of all, bottled nitrogen contains no moisture at all (unlike the air that comes from the gas station's compressor). Second, pure nitrogen, by definition, contains no oxygen (air is roughly 80 percent nitrogen and 20 percent oxygen). While the moisture and oxygen in air will eventually contribute to the rusting of the inside of the wheels, pure nitrogen will not.
RAY: If you had a truck and you had 18 tires and wheels at $500 a pop, then using nitrogen might be worth it. But we really can't recommend that you go through the trouble for a passenger car. I mean, when's the last time you heard someone say "I had to take my car to the crusher because the inside of the wheel rims rusted away"?
TOM: Right. In the grand scheme of things, using pure nitrogen in your tires hardly seems worth the effort or the expense - unless, of course, you can steal it from the place where you work!
The Magliozzi brothers' radio show "Car Talk" can be heard each Saturday at 10 a.m. on KUER FM 90.1 If you have a question about cars, write to Click and Clack Talk Cars c/o King Features Syndicate, 235 E. 45th St., New York, NY 10017.