Originally posted by afi292+May 3 2004, 10:04 AM--><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (afi292 @ May 3 2004, 10:04 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-Racer X@May 2 2004, 11:25 PM
This debate rears it's head from time to time here. Here's the skinny.
PVC (Poly Vinyl Chlorate) decomposes into several chemicals when incinerated, most notably HCl vapor. HCl, as in Hydrocloric Acid. But a vapor. Now, no one knows the exact temperature at which this decomposition happens, since the documented tolerances tend to vary from source to source. DuPont (the defendant) says one thing, the plaintiffs say another. I tend to agree with the plaintiffs based on my own experimentation with PVC, but we'll save that discussion for another day.
Bottom line is this, and again, this is based on my own personal experience with PVC in a vehicular application:
Depending on the type and grade of PVC (yup, there are different types), there is a small chance that extremely high underhood temperatures can cause PVC not to incinerate, but to outgas small amounts of HCl vapor. Again, different PVC sources outgassed at different temperatures. Some as low as 130F, some didn't outgas at temps as high as 300F, which would never happen under your hood, unless your car caught fire. In which case I hope to hell you're watching said fire from a safe distance.
In the instances where the outgassing occurred, the amount of vapor wasn't significant enough to cause combustion chambers to melt or anything. In fact, it was just barely measurable. However, prolonged exposure to these vapors could very well cause permanent damage to your engine. How long would it take? No idea. All I know is that the vapor can be produced under certain condiitions, and isn't exactly a noble gas.
IMHO, to be safe, I'd use ABS plastic to avoid any issues, since it doesn't outgas any caustic vapors when heated or incinerated.