JUST FOR FUN DEPARTMENT: In 1978, the Pontiac division at General Motors received an unusual letter about a great mystery. We’ll assume the letter and what it said was true. Snopes says yes, it was. If not, well, it’s a heck of a good yarn.
The letter:
“You’re going to think I’m crazy, but please hear me out. My family loves ice cream. Every night, the kids take turns picking a flavor, and I drive to the store to get it. Now here’s the weird part: I recently bought one of your new Pontiacs, and I swear—every time I buy vanilla ice cream, the car won’t start.
“If I buy chocolate, strawberry, or anything else—it starts just fine. I know this sounds ridiculous, but something about this car does not like vanilla.”
At first, the customer service team chuckled. But GM had a policy every customer complaint had to be investigated. So they sent an engineer.
To his surprise, the car’s owner turned out to be a perfectly reasonable, well-spoken man. Nothing nutty about him. Together, they drove to the grocery store and picked up vanilla ice cream. Sure enough—when they returned to the car, it wouldn’t start.
The test continued for several evenings. Strawberry? No problem. Chocolate? Smooth as silk. Vanilla? Dead silence.
Now, the engineer wasn’t ready to believe the car had a grudge against vanilla. So he started analyzing everything—time of day, fuel levels, ambient temperature, even parking spots. Eventually, the clue came from the store layout itself.
Vanilla ice cream, being the most popular flavor, was stocked right near the front of the store and the other flavors were at the back of the store. So when the customer bought vanilla, the round trip was much faster—just a couple of minutes in and right back out.
That quick turnaround time turned out to be the key. The engine wasn’t cooling down enough, and vapor lock was forming in the carburetor—air bubbles from evaporated gas were keeping fuel from flowing properly.
Thanks to one persistent customer and his love of vanilla, GM engineers discovered a design flaw they’d missed in testing. What started out sounding like a joke turned into an engineering breakthrough—all because someone took the time to listen.
And yes, the car eventually got fixed. But to this day, it’s known inside GM as “The Vanilla Ice Cream Case.”
MORE ESSAYS BY CHUCK:
- The crook who grew up to be a shoe
- RV awnings are reminiscent of a simpler time in America
- The father who turned his boy into a pickle
- From the archives: Random observations from the road in 1988 America
- How observing pavement helped create a retailing empire
RVT1221
Great story thank you.
Ahh. Vapor lock. Brings back memories. Not at all fond memories, just memories.
Vapor lock was an issue with my 1957 Chev 283 as well. The vapor lock would happen right at the fuel pump located near the exhaust manifold. Often seemed to happen when you were trying to pass another car and when you needed the extra surge of gas. Half-way passed the other car the engine quit, and I’d need to pull back in. Embarrassing and a little dangerous. I had to pour a beer over the fuel pump to get it going again. A terrible waste.
And there you have the difference between automobile manufacturing and rv manufacturing.
I’d never heard of this one before. Great that cars have improved to eliminate this problem. Our family had a ’59 Pontiac station wagon that suffered from vapor lock every now and then.
Reading this makes me thankful that I’m retired and no longer an automatic transmission specialist. Over the years I’ve encountered many of these “mystery” mechanical, or in modern vehicles add in electronic problems, that are sometimes almost impossible to diagnose. As a matter of fact, I have to admit I had a couple issues that me or my buddies in the business could never solve! 🙂
I don’t know. Sounds a little “urban legendy” to me. Grocery stores tend to place the popular items in the back so that you’re forced to walk past the less popular items in hopes that you’ll impulse buy something else on your trip. The idea that there’d be a separate ice cream section for the popular flavors up front in an environment already limited in space seems unlikely.
I thought the same thing!
Well this article brings back an unpleasant memory! I bought a new off the floor 1964 Pontiac Bonneville with a 389 V-8. At the first Mn-ND cold snap & about 3,000 mi. on the odometer – it would not start! This continued to the point of frustration when I called the dealer and told them to come and get it and fix it! As I was waiting in the lounge another customer remarked:,”… wouldn’t start?” “you could sit in the backseat with an ice cream cone in August in that thing and it wouldn’t start!” I never tested that and they never solved the problem either! I just lived with it for another 2 years! AAA was glad to see me go!
In the 70’s a combination of higher normal engine temps related to EGR (exhaust gas recirculation – and other emission control systems) was very common in mid to high temperature climates. We in the industry referred to it as “percolation”. Later, thankfully, modern fuel injection systems replaced the “fuel boiling float bowls” in carburetors. Attempts at programming electric cooling fans to continue running after engine shut down were tried but the best way to avoid percolation on a carbureted engine is to leave the engine idling for short errands. That’s not practical from a “theft standpoint” though!
The phenomena of “hot soak surge” was also common in the era. The hot engine would start and idle but trying to accelerate resulted in bucking and stalling – same cause -“premature fuel vaporization”. Evaporated gas bubbles in the fuel line.
I had a brand new 1978 Pontiac Grand LeMans. Vapor lock was not my problem, the catalytic converter was. I had to have it replaced 3 times. In those days, if they fixed it once, and it had problems, they replaced it free. After the 3rd time, it went on fire, my whole car and the field off to the side of road was burnt to a crisp. Besides shocking and scary, it was heartbreaking. I loved that car.
Thank you, Chuck, for sharing the story, and particularly the demonstration of the value of listening, of taking seriously, rather than dismissing the apparently weird, stupid, strange or “impossible.” Have a great week and safe travels!
Wow! Amazing story, Chuck.