Decaying rubber has whistle effect

ERJ staff report (TP)

Massachusetts − A few weeks ago, I started having performance issues with my 2003 Mercury Sable. After a couple of days, I popped the hood and started looking for the usual suspects. About that time, my wife wandered by and asked what that funny sound was, reported David Nason for Design News.

She was right; there was a definite hissing sound. I put on a pair of gloves and started feeling around. Then, the vacuum from a rubber elbow grabbed the edge of my glove, and, wrapping my finger around the hidden elbow, I changed the sound.

This is the PVC elbow that comes off the intake to the PVC valve. It was cracked on the outside, but more interestingly, it looked like it was chewed up on the inside. I speculated that the oil fumes from the crankcase must have affected it. One trip to the auto parts store and a quick swap was all it took to fix the problem.

That night I remembered how my son's 2002 Ford has had a whistle for a few months, and we even went so far as pulling the intake manifold looking for the leak, but we didn't find it. On a whim, I grabbed a pair of gloves, and using one as a rubber piece, I felt near the similar elbow on his car. Sure enough, the glove was drawn to it and the whistle ceased. Again, one trip to the auto parts store solved the problem.

I have had a 1985 Dodge van since it was new and a similar hose on it is still the original. There is no sign of decay or being chewed up by the presence of oil. Yet, the molded Ford elbow is stocked at two different auto parts store and clearly shows signs of decay. I don't know whether to blame the manufacturer for not specifying the correct rubber for the elbow, or if it's an environmental issue that forced a material change, but this elbow is definitely a part to watch.

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