Mercedes-Benz replaced the Typ 290 in 1937 when it revealed the new Typ 320 lineup, which offered a better power-to-weight ratio and extensive bodywork choice.
Like the 290, the 320 was available with two wheelbases and a few shapes, or just as a bare chassis. Apart from the sedan and two-door convertible, the carmaker offered a four-door convertible with removable side windows.

Thanks to its long wheelbase of 3.3 m (130”), the Tourenwagen featured a long engine compartment with a pair of spare wheels mounted on its sides. The headlights were enclosed in more spherical housings, attached directly to the front fenders on cast legs. When the driver completely opened it, the car resembled the torpedo-style vehicles from the ’20s, with the removable roof folded behind the cabin. Its shorter rear fenders cleared the path for the back door, easing up the ingress and egress for the back-seat passengers. For the same reason, the carmaker installed a set of side steps between the front and rear fenders.

Mercedes-Benz placed two leather-clad benches in the car for up to five occupants. The front one was wide enough for three adults, but the floor-mounted gear stick prevented a third middle passenger. A significant improvement for the car was adding a coolant-temperature gauge. The carmaker mounted it on the instrument panel next to the speedometer and tachometer.

The 1938 model of the W142 Typ 320 was the last evolution over the model 290.
It featured improvements for comfort and high-speed efficiency.

The Typ 320 featured a 3.2-liter engine in the beginning, in February 1937 when it was shown at the International Automobile and Motorcycle Exhibition in Berlin. With it, the brand closed a gap in the market between medium-sized vehicles and vehicles of the largest format. The four-door version with streamlined bodywork was suspected to be designed by Spohn, one of the most prolific aerodynamically-shaped bodywork builders in the era.

The initial 3.2-liter engine featured 12 counter-weights for the crankshaft, to reduce engine vibrations. The solution worked and the engine ran smoothly. The former updraught carburetor was replaced by two downdraught carburetors. The previously used 4-speed transmission with overdrive function (it was, actually a three-speed gearbox), was replaced by a fully synchronized 4-speed gearbox supplied by ZF company. The fourth gear had a 1:1 gear ratio, which made the engine ran 26% lower than the previous version, at the same speed. That made the Typ 32 W142 IV faster and with a better fuel-efficiency. In late 1938, due to the shortage of high-octane fuel, the engine displacement was increased to 3.4-liter, in order to keep the same 78 hp.

The chassis featured an independent front suspension with a transverse leaf spring. At the top, the wheel was attached to a suspension arm that rested on a helical spring on the inside. The rear dual-joint swing axle had two helical springs on each side, one behind the other. Dual-action hydraulic lever-type dampers were installed on both front and rear axles.

In 1937, the aging Mercedes-Benz 290 was replaced by the newer 320.
At last, the customers could have more power for the luxury German brand and a wider choice of bodyworks.

Like its predecessor, the 320 was offered with two wheelbases and it was available in more shapes. For those who wanted to go for a custom coach-builders, Mercedes-Benz offered the car as a chassis. The Cabriolet B was one of the best convertible versions built in-house by the German car-maker.

With a long wheelbase of 3.3 m (130”), the Cabriolet B featured a long hood with side-mounted spare wheels and long arched fenders. The headlights were mounted between the fenders and the engine compartment, not requiring a bar anymore as it was for the 290 model. In the back, there was a locking trunk.

Inside, the car featured two seats in the front and a bench in the rear The instrument panel featured a coolant temperature gauge. All three dials were installed in the middle of the dashboard. A big, four-spoke, steering wheel increased the luxurious look of the car.

Before 1938, the engine was an inline-six with a 3.2-liter displacement. Due to the expected shortage of fuel quality, in 1938 the engine was increased up to 3.4-liter, but without decreasing the power. The gearbox was a 4-speed manual and a separate lever for a high-gear, needed for the highway cruising, with a 1: 0.73 ratio.

The Typ D was launched as an extension of the Cabriolet B, with a four-door configuration and maximized passenger capacity of up to four.
The B-pillar, which was missing on the B-model, was reintroduced on this sporty-four seater. Style elements were carried on from its siblings, such as body shell design complete with the signature split-windshield. While trunk volume was not quite the vehicle’s strength, it provided enough room for luggage for two. Unlike some of its stablemates, the D-model was available with a choice of two petrol units displacing 3.2 L and 3.4 L respectively.

The typ 320 N Kombinationswagen was the the N Coupe’s “softer” brother.
Softer because of its actual soft-top and not because of a marshmallow interior and chocolate dashboard frosting although, it such was the case, it would have probably been a favorite among sweets-lovers. The car follows the same design pattern as its hard-top stable mate as well as internal parts, including the popular 6-straight petrol unit. The split-windshield was kept while spare-wheel mounts were moved to the rear end, contributing to the car’s fresher, leaner look.

The 320 N Kombinations-Coupe is the transformer-car of the 30’s with a 2-mode drive as either a coupe or a cabriolet.
Design was taken a step further with the vehicle having received a more streamlined body complete with corrugated sidelines and flawlessly interlinked door sills and front/rear fenders. Only the front end with double-row side vents and wheel design was carried over form the regular models. While the car can easily pass as a coupe, it actually sports a carefully camouflaged removable hard-top for open-top driving enthusiasts. Although the vehicle was visually revamped, it was powered by the same 6-straight 78 hp petrol engine.

The typ 320 Limousine may e described as a chubby car.
Elegant nonetheless but chubby. For reasons rather concerning safety than styling, the car’s lines were thickened, especially around the cabin, contributing to this four-seater’s overall sturdy appearance. The front end saw a slight decrease in size and the addition of multiple gill-like side vents while the roof received a large manually-operated sliding panoramic roof that predated the ulterior birth of the Targa sunroof type. More elegant than the saloon, the car’s interior was also updated to cater for possible owners’ demands.