What is de-carbonization?

Dear Car Talk

Dear Car Talk | May 01, 1992

Dear Tom and Ray:

In a previous column, you referred to "de-carbonizing" an engine. What is "de-carbonization?"

RAY: 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.

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