Collectors are often sorted into distinct categories: curators, preservationists, drivers, and restorers. John Groendyke was all these things and more.

It was natural that John’s passion and care would extend to his world-class car collection, which spanned the height of pre-war engineering and design. His name was a familiar sight at the Amelia Island Concours d’Elegance, Pebble Beach Concours d’Elegance, and Concours of America over several decades. Every car he showed was authentic, with no expense spared to ensure it was as correct as possible.

But his commitment to authenticity and correctness did not mean his cars were kept for display alone. He drove them, believing they were not simply static works of art to admire but vehicles to be used. Groendyke would regularly take his 1930s Cadillac V-16s up to 70 mph on the highways around Enid, Oklahoma—a terrifying thought for many collectors, but these were still cars to him and should perform as such.

But his commitment to authenticity and correctness did not mean his cars were kept for display alone. He drove them, believing they were not simply static works of art to admire but vehicles to be used. Groendyke would regularly take his 1930s Cadillac V-16s up to 70 mph on the highways around Enid, Oklahoma—a terrifying thought for many collectors, but these were still cars to him and should perform as such.

His longtime collection manager and friend, Dustin Whitney, recalled that Groendyke never showed much interest in using a car transporter when they became popular. All the cars needed to move under their own power; after all, they weren’t going to push them.

“He had an extraordinary eye for great cars, particularly the finest pre-war American automobiles, and his standards were incredibly high. If a car wasn’t already among the best, he made sure it became one of the best,” said Gord Duff, president of RM Sotheby’s.

RM Sotheby’s will offer 13 automobiles from The Groendyke Collection at its Arizona auction on 28–29 January 2027. The selection is led by a 1935 Mercedes-Benz 500/540 K Cabriolet A and also includes five Cadillac V-16s, among them two Pebble Beach Concours d’Elegance class-winners.

“John was more than a longtime client. He was a dear friend and someone who had been part of the RM Sotheby’s family for more than 30 years. But what I’ll remember most is his kindness, his enthusiasm, and the genuine joy he found in collecting. He was always looking for that next special car, and it was a privilege to share that passion with him over the years. There will never be another John Groendyke, and we’re honored to bring these remarkable automobiles to the next generation of collectors,” added Duff.

Groendyke was a fixture at the Pebble Beach Concours d’Elegance, attending with an automobile for approximately 30 years. His restorations earned numerous awards at Pebble Beach, Amelia Island, and the Concours of America.

He also had a particular enthusiasm for building collections within his collection. Over the years, he assembled complete groups of Chrysler letter-series cars and 1950s Cadillacs, as well as an extraordinary collection of more than 25 Cadillac V-16s representing many of the marque’s most desirable 1930s body styles.

His collection typically numbered between 30 and 50 automobiles at any given time, but it was constantly evolving, with new acquisitions, occasional trades, and even the return of cars he had previously owned.

The Cadillac V-16 Models

Leading this group is a 1936 Cadillac V-16 Convertible Coupe by Fleetwood, restored by Steve Babinsky’s Automotive Restorations and awarded first in class at the 2019 Pebble Beach Concours d’Elegance.

Equally compelling is the 1930 Cadillac V-16 All-Weather Convertible Sedan by Murphy, featuring a one-off body created in period by the Pasadena coachbuilder. Purchased by Charles S. Howard Jr., the Cadillac later resided in the Mozart and Andrews collections before joining The Groendyke Collection. It has appeared at the Pebble Beach Concours d’Elegance multiple times, earning a first-in-class award.

The 1933 Cadillac V-16 Convertible Coupe by Fleetwood adds both rarity and a connection to motion-picture history. The 117th of 126 Cadillac V-16s built for 1933, it is believed to be one of only two surviving examples of its body style. Its original owner, inventor Theodore W. Case, developed Movietone, a system that synchronized sound with motion pictures. Sold new through Lewis E. Springer’s Cadillac dealership in Auburn, New York, the car has also been shown at Pebble Beach.

Also featured is a 1930 Cadillac V-16 Roadster by Fleetwood, formerly of the Frank and Milli Ricciardelli Collection. Presented with an attractive older restoration and a charming color combination, it joins the other featured Cadillacs in being recognized as a Full Classic by the Classic Car Club of America.