From the airport all the way to Havana on a cool winter day, you don't just smell the diesel smoke, you taste it.

Just ahead of President Obama's historic visit to Havana this week, I visited the city on a trip with our friends from Car Talk to get a sense of how ordinary Cubans — those without the political horsepower to drive new Peugeots from dealerships set up for the elite by the Cuban government — have managed to piece a transportation network together. Like everything about Cuba, our impression was out of date and often completely wrong.

A significant percentage of the cars here in Cuba are old and American. Prior to the revolution that ousted Batista and put Fidel Castro in power, America shipped cars to Cuba by the boatload. Cuba predated Las Vegas as a haven for Americans with money to spend — and organized crime syndicates that were eager to stuff it in a suitcase. Neither party was interested in landing at the airport in Havana and driving around in some European microcar, so American cars flooded here like it was a 50th (or 51st after 1955 when Alaska joined the union) state.

There are Fords, Chevrolets and Plymouths here, but by far, the car that seems to be best represented here is the 1950 to 1953 Buick. In 2016, you'll see one at every stoplight.

Diesel for decades

A classic American car emits diesel exhaust as it cruises down a Cuban streetCuba pumps as much carbon into the atmosphere as Mexico does, but Mexico has 10 times the island's population. (Photo: Craig Fitzgerald)

We tend to think that those cars are still driving around with six enormous pistons rattling around in their cylinder bores with worn out rings, pouring a blue cloud of oil-laced emissions through the exhaust.

But, it turns out, that's completely wrong. The exhaust isn't blue; it's black, and it comes out in a thick column every time an enthusiastic driver squeezes the accelerator under his foot. Drivers aren't "rolling coal" as some kind of a symbol of dominance over the Prius in the next lane. They're doing it because it's the way diesel engines work here. It's exactly the way they worked in the United States, too, when we drove around in diesel-powered Oldsmobiles in the 1970s.

For decades, Cubans with access to old American cars did whatever they could to keep the original V-8 and inline six-cylinder engines running. But, in a bid to help Cubans overcome the crushing reality of elevated gas prices in the mid-2000s, the Cuban government went on a buying spree, purchasing thousands of used, late-model diesel engines from Japan and Korea. Cubans with the funds to do so purchased the engines from the government and retrofitted their American land yachts to run on diesel.

Every year, Cuba's cars and trucks contribute to the island nation's 3.4 metric tons of carbon in the atmosphere. That's about what Mexico churns out, but with more than 10 times Cuba's population.

What makes Cuba unique is the reliance on older cars as daily transportation. Here in the United States, old cars are generally a hobby. Most people aren't driving their 1959 Oldsmobile Dynamic 88 to work. They emit 1950s-era hydrocarbons into the atmosphere, but if drivers put 5,000 miles a year on them, it's a lot. In other Central and South American nations, drivers might be driving older cars and trucks from the 1970s and 1980s, but they're smaller, lighter and more fuel-efficient.

Making do by mixing and matching

Our driver Edel gave us the rundown on the two taxis he and his partner Nidalys carted us around in for two days. His car, a 1956 Ford Fairlane, had a four-cylinder diesel engine from Hyundai. I asked him how old the engine was. "When you're Cuban and the government sells you a new engine, you don't ask how many miles are on it," he laughs. "You're just thankful to have it."

The engine mates up to a manual, five-speed Hyundai gearbox through an ingenious mechanism that allows the transmission to shift via the Eisenhower-era Ford's three-speed shifter, mounted on the steering column.

So far, so good, but the drivetrain was designed with gear ratio of 3.27, which kept the RPMs low on American highways. The high-compression Ford V-8 originally in Edel's Fairlane had ample torque to allow the engine to power the car up long hills without issue.

Here's the rub. The Hyundai diesel doesn't have that kind of torque. That means that when Edel has to climb a long hill, he has to downshift and plant his foot to the floor, releasing a column of black diesel smoke out the exhaust pipe. This isn't the fancy "clean diesel" we get in the United States. This is the dirty, sooty old diesel fuel that's literally about four grades below what people in the Northeast run through their furnaces.

One of the longest hills we ascend is at the exit of the tunnel near the Rio Almendares in Havana. About 500 feet from the mouth of that tunnel, the lingering diesel smoke from thousands of cars and trucks is so thick it obscures your vision and makes your lungs burn. For an American used to clean cars subjected to rigorous emissions inspections and vented tunnels with filtered exhaust fans, it's choking. For Cubans, it's business as usual.

No fast lane for change

Classic car convertible in CubaCubans try to keep their cars in the best shape possible, but the U.S. trade embargo has made obtaining parts for old cars difficult. (Photo: Craig Fitzgerald)

When I asked Edel what he'd do if new cars were suddenly available, he told me he'd move on to a modern car, but that's not going to happen overnight. Those government-run Peugeot dealerships are few and far between now, and sell cars that might cost $30,000 elsewhere, for the stratospheric price tag of $240,000.

But the continuing trade embargo means that Edel can't just pick up a Summit Racing catalog and order a 4.10 ring and pinion set that would maximize the torque available from his four-cylinder Hyundai the way we can. He can't buy a turbocharger. He can't even buy a rear brake wheel cylinder with the correct 19mm bore, so he has to rely on whatever he can find. When you're scrambling to find brake parts, you're not focused on your carbon emissions.

Cuba gets that there's an environmental crisis going on in the world. Our hotel has decals on every bathroom mirror just like in the United States, urging guests to conserve water by not requesting new towels every day. But the country is hamstrung by an embargo that keeps small, insignificant parts out of the hands of Cubans who could then concentrate on the cloud of diesel smoke at the end of that tunnel near the Almendares.

The baggage claim at the Havana airport is littered with gigantic shrink-wrapped packages containing televisions, DVD players and full sets of tires, as Cubans are slowly allowed to bring items back from the United States. For now, Edel hopes a friend can bring a ring and pinion set home after a trip to America, but it might be years until he gets it. Until he can pick up the phone and order that ring and pinion set from a supplier in the U.S. and have it delivered to his front door by UPS, he and other Cubans are going to be suffering the effects of the country's diesel emissions.

For more on Cuba's cars and the people who keep them running, drop by the BestRide website. Craig Fitzgerald is an editor for BestRide.com and blogs regularly for Car Talk.