Causation…how a sweet tooth made a car company more lean

melting vanilla ice cream

This week’s Lighter Side article is a well-known tale about customer service and how logical thinking can explain the relationship of things which may seem totally unrelated.

The story goes that a complaint was received by the Pontiac Division of General Motors. The customer described how every night after dinner the family would decide what kind of ice cream to have for dessert.  He would then drive in his new car to the ice cream shop to buy the chosen flavour. Every time he bought the vanilla flavour and started back home, the car wouldn’t start. If he bought any other flavour, the car started up completely fine. After many such instances, he concluded, of course, that the car was allergic to vanilla ice cream.

Melting the ice cream conundrum

After several complaints to the car company, the Pontiac President decided to send an engineer to check it out. For a statistically significant number of nights, the engineer joined the man on his drive to the ice cream shop. Sure enough, when they bought vanilla ice cream the car wouldn’t start, but for any other flavour the car was fine.

Being a logical man, the engineer refused to believe that this man’s car was allergic to vanilla ice cream. He continued his visits and jotted down all sorts of data: time of day, type of fuel used, time to drive back and forth, etc.

He observed that the man took less time to buy vanilla than any other flavour. Why? Because of the layout of the shop. The proprietor had set up a separate counter near the door to serve only those customers ordering vanilla, as it was the most popular flavour.  All the other flavours were served at a larger counter near the back. Also, since the store owner was understaffed, customers wanting flavours other than the vanilla flavour had to wait for longer times. Those buying vanilla were in and out in a minute or two.

So it turned out that time, not the car, was the problem!  Now, the question for the engineer was why the car wouldn’t start when it took less time.

And the reason why is…

The answer he came up with was: “VAPOUR LOCK”. Due to ambient warm temperatures and humidity, a vapour lock formed in the new car’s carburettor when the engine was turned off. This vapour lock had enough time to dissipate if the man ordered any flavour other than vanilla. But if he ordered vanilla, he was in and out of the shop so fast that the vapour lock hadn’t had time to clear, and thus the car wouldn’t start. This phenomenon of vapour lock happens under a combination of new car, thin oil, tight engine fits and low torque starters. However, after sufficient use, say, 1000 miles, this problem disappears.

Now, if you have a sweet tooth, this is definitely an experiment you should try!

More Lighter Side articles from Pamela Hellig.

Pamela Hellig