When Others Take Vacations, We Head to the Ends of the Earth: Hot & Cold Vehicle Testing

 

The Ultimate Checklist: Hot Tests, Cold Tests, and the Australasian "Pinch Hitter"

In the vehicle development pipeline, there is a ruthless final verification phase. We take completed prototypes and push them to their absolute limits to ensure they perform exactly as programmed and to flush out any unforeseen design anomalies. The powertrain calibration teams—responsible for engines and transmissions—along with the chassis control teams mastering ABS and ESP, are the ones who most frequently pack their bags for these notorious "extreme environment trials."

In this line of work, climate and geography are everything. Consequently, while the rest of the world is packing for leisurely summer or winter vacations, these engineering teams are heading in the exact opposite direction. We hunt down the most inhospitable terrains on the planet, split strictly into "Hot Tests" during the peak of summer and "Cold Tests" in the dead of winter.

For our powertrain trials, the legendary proving grounds included Death Valley near Las Vegas and the Sierra Nevada mountains in Spain. (In South Korea, Mt. Palgong in Daegu or Mt. Jiri in Namwon were favored summer altitudinal tracks). Conversely, when winter arrived, we packed our thermals for International Falls in the US or the frozen expanses of Sweden.

Occasionally, we would charter flights to Australia for summer testing. Australia acted as our ultimate "pinch hitter." If a test vehicle wasn't fabricated in time for the standard Northern Hemisphere summer, we couldn't afford to wait a whole year. Instead, we would catch a flight to the Southern Hemisphere, chasing the summer that arrived six months later.

45deg (C) Heat, "Zebra Cars," and the Assault on 3,000-Meter Peaks

Summer and winter testing demand entirely different engineering focus areas.

Summer tests are conducted in regions of extreme heat or high altitude. Climbing up to 3,000 meters above sea level, it wasn’t uncommon for colleagues to complain of sudden dizziness. At these high altitudes, we intensely monitor whether vapor locks form within the fuel supply system or if evaporative emissions leak.

More importantly, we observe how intelligently the ECU (Engine Control Unit) compensates for the sudden drop in atmospheric pressure, which drastically reduces the mass of oxygen molecules sucked into the engine chambers.

Because of this, a hot test team never stays in one place. Whether in Death Valley or the Sierra Nevada, we spent every single day driving hundreds of kilometers through barren landscapes. If you have ever spotted a convoy of vehicles on public roads covered in dazzling, zebra-like camouflage patterns or heavy vinyl wraps, you were looking at a vehicle evaluation team. Back then, I was the man behind the wheel of one of those wild machines.

The physical toll of hot testing is difficult to overstate. By noon, the ambient temperature easily skyrockets to 45deg (C), and you must endure this relentless heat all day. To make matters worse, because these test fleet units are aggressively retrofitted prototypes, most of them either don't have air conditioning installed, or the refrigerant has leaked out, turning the cabin into a literal sauna.

After climbing up and down a 3,000-meter peak multiple times in a mobile oven while staring intently at calibration maps on a laptop screen, exhaustion sets in rapidly. Your throat burns, your skin is slick with sweat, and if the laptop—basking under direct, unfiltered sunlight—suddenly overheats and crashes, you find yourself heading back to the lodge in a state of sheer mental numbness.

The Zen of Winter Testing and Korean OEMs' Obsession with First-Crank Startability

In stark contrast, winter testing revolves entirely around "Cold Startability." The absolute core metric here is achieving a clean, decisive engine ignition on the very first crank—even after the vehicle has cold-soaked in -25deg(C) temperatures.

To properly validate this, the vehicle must sit undisturbed for at least eight hours to allow the engine block and fluids to completely stabilize with the freezing ambient air. Consequently, we didn't drive long distances during the day. Our daily routine involved wrapping up field calibrations early in the evening, meticulously parking the fleet in a neat row for the next morning’s cold-start run, and retreating to a warm room to process the day's telemetry data.

What I found fascinating during these global trials was that South Korean automakers (OEMs) exhibited an almost terrifying obsession with this first-crank startability and the absolute, clockwork-like stability of post-start "Idle Refinement."

Even when evaluating premium European brands, I rarely witnessed their engineering teams stress over initial start noise and idle vibrations to the degree the Koreans did. Ultimately, this intense engineering focus is driven by the extreme sensitivity of the end consumers in the Korean market. (Though today, with the dawn of electric vehicles, the automotive world has inherently entered a realm of absolute silence.)

The $5 Casino Buffet in Death Valley vs. Spain’s Sandwich Cruelty

When we traveled to Death Valley or Volkswagen’s Proving Ground in Phoenix, there was one undeniable perk: the abundance of nearby casinos.

I remember evaluating a fleet of VW Lupo vehicles. The team operated as a cohesive unit, comprised of the vehicle evaluation team from VW headquarters, the transmission team, and our engine calibration group. We always had breakfast at a restaurant attached to a nearby casino, and the price was unbelievably cheap—around $5.

When I asked why it was so inexpensive, they explained it was a deliberate hospitality service for patrons who had lost money gambling through the night. The venue featured an elegant live-omelet station where a chef prepared eggs to your liking, and even complimentary ice cream. Thanks to this, we fueled our grueling days with a lavish breakfast for just a five-dollar bill.

Conversely, heading to Europe for hot testing triggered a completely different kind of raw survival story. Organizing an altitudinal trial in the Sierra Nevada mountains near Granada, Spain, was a massive logistical project, starting with airlifting the prototype fleet from Germany.

Typically, we chose a major transportation hub like Frankfurt as our staging ground to assemble a convoy of around ten vehicles, including prototypes and baseline benchmark cars. After checking if the team was physically primed for the massive overland journey and verifying local road and lodging logistics, we would drive the entire fleet thousands of kilometers directly to the destination.

Moving a massive engineering convoy across European borders rarely went smoothly. From minor accidents with local vehicles and getting pulled over by local police for traffic violations, to lost luggage or team members suffering from stomach bugs due to the change in local water, the journey itself was a logistical war even for seasoned veteran engineers.

"Will I Return Home with My Teeth Intact?" Survival Linguistics in Europe

During one of our overland journeys from Germany to Spain, our convoy stopped for the night in a quiet, secluded village in rural France. We walked into a local diner for dinner, but the owner didn't speak a word of English, and not a single engineer in our group spoke French.

We stared intently at the menu, but the only word we could decipher was "Sandwich." Naturally, the entire team ordered sandwiches. However, what arrived at the table was far from the soft, sliced bread we had envisioned. It was a brutally hard, rustic baguette sliced lengthwise with a single, massive sausage tossed rudely in the middle.

As I chewed through that incredibly tough bread until my jaw throbbed, a single thought consumed my mind: “Will I actually make it back to South Korea with my teeth intact?”

Carrying the memory of that painful dinner, we finally arrived at our destination in Spain after a two-day drive from Stuttgart. Here, the probability of encountering English was also virtually zero, and none of us spoke Spanish. A sudden wave of anxiety hit me: What are we going to eat this time?

The moment we checked in, I sprinted to the hotel reception desk. For an hour, I stood there with wide eyes, absorbing an intensive crash course in "Survival Spanish" from the receptionist. I desperately scribbled down vital survival phrases like "Una cerveza, por favor" (A beer, please) and "Gracias" (Thank you), learned how to count, and noted down local dishes that were safe to order. (It was during this frantic session that I first discovered Paella, Spain’s iconic seafood rice dish.) Only after securing this linguistic survival kit could I finally clear my mind and focus on my core mission: vehicle testing.

Yet, once the grueling testing schedules were successfully completed, Spain always offered a magnificent reward to its engineers. While the crimson walls of the Alhambra in Granada, the bustling local markets, and the architecture of Barcelona on the return trip were beautiful, the image most deeply burned into my memory is the fiery passion of Flamenco.

Sitting in a local tavern for post-trial dinners, dancers would suddenly stamp their feet right in front of our table. The sheer, dynamic energy and movement of the Flamenco wiped away every ounce of exhaustion accumulated from a long day of swallowing dust and sweating under a 45deg(C) sun. It was raw, unadulterated passion.

Chasing the absolute operational limits of automobiles by traveling between the extreme poles of the earth, those memories of the Autobahn and Death Valley—drenched in the sweat of dedicated engineers—still burn brightly in a corner of my heart.