Flachkühler (pronounced flak-koo-ler)
In
German, (literally "wide cooling device" (radiator)), a name adopted by
Daimler-Benz to describe the W111 Mercedes-Benz coupés and cabriolets built
(1969-1971) with a lower, wider radiator grill than the earlier W111 (and W112)
coupés and cabriolets (1961-1969).
Circa
1860s: The construct was Flach + kühler.
The adjective flach (the singular
flacher, the comparative flacher and the superlative flachsten) (shallow (wide and not deep))
was from the Middle High German vlach,
from the Old High German flah, from the
Proto-Germanic flakaz of uncertain
origin. The construct of the noun Kühler ((1) cooler (anything device
which cools) or (2) radiator (of an ICE (internal combustion engine)) was kühlen + -er. Kühlen was from the Middle High German küelen, from the Old High German kuolōn & chuolen, from the Proto-Germanic kōlōną & kōlēną and
related to kalaną (to be cold). It was cognate with the Hunsrik kiele, the Luxembourgish killen, the Dutch koelen, the Saterland Frisian köile,
the English cool (verb) and the Swedish kyla. The German suffix -er (used to forms agent nouns etc from verbs (suffixed to the verb
stem)) was from the Middle High German -ære
& -er, from the Old High German -āri, from the Proto-West Germanic -ārī, from the Proto-Germanic -ārijaz, from the Latin -ārius.
When used as an adjective, kühler
was a comparative degree of kühl ((1)
cool (of temperature), (2) calm, restrained, passionless and (3) cool, frigid (particularly
of the emotions)), from the Middle High German küele, from the Old High German kuoli,
from the Proto-West Germanic kōl
& kōlī, from the Proto-Germanic kōluz & kōlaz, from the primitive Indo-European gel-. It was cognate with the
Dutch koel and the English cool. Flachkühler
is a noun; the noun plural is Flachkühlers.

1966 Mercedes-Benz 300 SE (W112, 1962-1967) Cabriolet (Hōchkühler).
The
dimensions of the grill used on the Mercedes-Benz W111 coupé & cabriolet
were dictated by the height of the 3.0 litre (183 cubic inch) straight six (M189; 1957-1967) engine used
in the more exclusive W112 (300 SE) versions.
The M189 was one of several de-tuned variants of the M198 used in the
300SL Gullwing & roadster (W198; 1954-1963) which had started life as the M186 in the
big 300 (W186 & W189, “Adenauer” 1950-1963, (the nickname referencing Konrad Adenauer (1876–1967; chancellor of the FRG (Bundesrepublik Deutschland (Federal Republic of Germany; the old West Germany) 1949-1990) 1949-1963) before revealing its competition potential by
gaining victories at the Nürburgring, the Carrera Panamericana in Mexico and,
most famously, the Le Mans 24 Hours endurance classic.
In the sports cars, the long-stroke six had been installed at an angle
of 50o and fitted with a dry sump which permitted a low hood
(bonnet) line but in the W111 & W112 the unit was mounted in a conventional
perpendicular arrangement and used a wet sump, further adding to the height,
thus the relatively tall grill. The
smaller sixes used in the car (2.2 litre (M127); 2.5 (M129) & 2.8 (M130))
were of a more modern, short-stroke design and didn’t demand such a capacious engine
bay but production line rationalization meant maintaining two different sets
of coachwork for what were low volume models was not viable.

1971 Mercedes-Benz 280 SE 3.5 Coupé (Flachkühler).
By
the mid 1960s however, Mercedes-Benz was well aware the gusty, high-revving
sixes with which the brand’s reputation had in the post-war years been re-built
were technologically bankrupt for an attempt to compete in the vital US market
where, for more than a decade, Detroit had been building the world’s finest
engine-transmission combinations. What
was needed was a mass-market V8 and because the big-block 6.3 litre V8 (M100 (1963-1981),
introduced in 1963 in the 600 Grosser (W100)) wasn’t suitable for down-sizing,
two physically smaller V8 ranges were developed, the first of which was
designated M116; released in 1969 and in displacements of 3.5, 3.8 & 4.2
litres, it would serve the line until 1991 (confusingly, there were two
iterations of the 3.8, the bore/stroke relationship altered for markets with
lower speed limits and more onerous emission regulations). The 3.5 came first and in 1969 it debuted in
the W111 coupé & cabriolet, designated 280 SE 3.5. By then,
the old 3.0 litre six had been discontinued so the tall grill, which had come to look rather baroque, was no longer required and shortly after production commenced, the factory took
the opportunity to modernize things with the new, lower & wider grill coming
to be known as the Flachkühler (literally
“flat cooler” and best translated as “flat radiator grill”, the engineers deciding
the earlier design should be referred to as the Hōchkühler (high radiator). Hōch (high, tall; great; immense; grand;
of great importance) was from the Middle High German hōch, from the Old High German hōh,
from the Proto-West Germanic hauh,
from the Proto-Germanic hauhaz, from the
primitive Indo-European kewk-, a
suffixed form of kew-; it may be
compared to the Dutch hoog, the English
high and the Swedish hög.

1955 Chrysler C-300 (top left and dubbed retrospectively the 300A), 1970 Mercedes-Benz 280 SE 3.5 Coupé (Flachkühler, top right), Rover 3.5 Coupé (bottom left) and Rover 3.5 Saloon (bottom right).
Although it's the 280 SE 3.5 Cabriolets which now command the highest price, what they miss is the coupe's lovely roofline, a style the factory reprised for the C215 coupés (1998-2006) but in fairness to Chrysler's stylists, the look was borrowed from them. For a brief, shining moment in 1955-1956, Chrysler offered their elegant “Forward Look”, the flirtation with restraint not lasting long as "irrational exuberance" washed over Detroit's studios but the influence endured longer in Europe, both the Mercedes-Benz W111 & W112 Coupés and the Rover P5 (1958-1967) & P5B (1967-1973) interpreting the shape. The Rover was a tale of two rooflines: the “Establishment” Saloon and the rakish Coupé, the latter the sort of thing described in barristers' slang as a "co-respondent's car" (ie the type driven by the sort of chap inclined to sleep with other men's wives and thus be cited in divorce proceedings while the man with the unfaithful wife would have driven a 3.5 Saloon).

1970 280 SE 3.5 Coupé. The lovely roofline was a highlight and it's a design best left
unadulterated although many haven't been able to resist adding reproductions (usually in anodized
plastic) of the chrome wheel arch trim fitted only to the W112.
Testing
a 280 SE 3.5 Coupé in 1970, the US magazine Road & Track greeted the
revised model with much the same feeling the press would a year later display when
Jaguar’s new V12 made its debut in the Series 3 (1971-1974) E-Type (XKE,
1961-1974), writing of the German car: “The vintage coupe gets a lovely new engine”. The testers came away most impressed with the
new power-train, the sheer quality of the build and the performance, the
ability to achieve 125 mph (200 km/h) and cruise at high speed for hours not of
great relevance in most of the US but anyway something to note of a large and heavy
machine of (by US standards) relatively small displacement. Criticisms were limited mostly to the
air-conditioning (it took European manufacturers decades to match what Detroit
perfected early in the 1960s) and the swing-axle rear suspension (admittedly a
state-of-the-art implementation but still antiquated). In a sigh of the times, the fuel consumption
of 15.8 mpg (18.9 mpg calculated in imperial gallons) was deemed “impressive”
but that needs to be assessed in the context of the performance and what other
cars in the era achieved. What Road
& Track didn’t foresee what was to come for the things as used cars. Noting the hefty premium charged for the
two-door coachwork and that new engine was also available in the four-door 300
SEL 3.5 (W109), the editors commented: “We wouldn’t give you
two cents extra for that hardtop [coupé] body (or the even more expensive convertible
[cabriolet] but
right now you have to take either that or the also expensive air-suspension on
the 4-door sedan to get the V8 engine.
And that is nice.” By
the mid 2020s, all else being equal, the 3.5 coupé sells for 4-5 times what’s
achieved by the sedans, the cabriolet at least ten-fold more valuable but
in 1970, who would have predicted that?

1970 Mercedes-Benz 280 SE 3.5 Cabriolet (Flachkühler, left) and 1968 Mercedes-Benz 280 SE Cabriolet (Hōchkühler, right).
Produced
only between 1969-1971, the two-door 280 SE 3.5s were always expensive and only
3,270 coupés and 1,232 cabriolets were built.
On the US West Coast, in 1970 a 3.5 Cabriolet listed at more than
US$13,500 and that was at a time when a Cadillac De Ville Convertible had a
base price of US$6,068 (although buyers typically would tick a few boxes on the
option list so usually paid around US$7,000; a 1970 Coupe de Ville two-door
hardtop listed at US$5,884). Of course,
the Cadillacs included a 472 cubic inch (7.7 litre) V8 and in terms of “dollars
per pound” they offered a lot more metal for the money but the customer profile
probably not often overlapped. Being
another age, the Mercedes-Benz was available with a four-speed manual gearbox
(an option Cadillac withdrew after 1953) which was rather clunky thing which
few choose but such is the rarity value, they have a following. The whole ecosystem of 280 SE 3.5 coupés and
cabriolets actually became a cult in itself, perfectly restored cabriolets
commanding prices in excess of US$500,000 and some German tuning houses will
charge more for examples modernized with attributes like ABS (anti-lock brakes and literally "anti-bloc-system"), later V8 engines,
transmissions and suspension. Even now,
although in essence the structure dates from the late 1950s and the mechanicals
a decade later, the appeal remains because the things are remarkably usable in
modern conditions and aesthetically, nothing Mercedes-Benz has made since has
anything like the elegance but then, nor have many.

1953 Morgan Plus 4 ("flat radiator", top left), 1955 Morgan Plus 4 (top right), 1969 Morgan Plus 8 (bottom left) and 2024 Morgan Plus 6 (bottom right). Thematically, since 1954 not much has changed although, under the skin, there is much is the modern Morgan that is "most modern".
Strangely,
the idea of the “flat radiator” had been around for a while in the vernacular
of collector car circles but it referred to another aspect of geometry. In 1952, Morgan of Malvern Link,
Worcestershire, was (as it is now sort of still is) an English cottage industry manufacturing pre-war sports
cars with more modern engines and they received advice from Lucas that because MG’s new TF (due for release in 1953) would have its headlamps integrated with the bodywork, production of the housing assemblies was ending. There being no
alternative supplier, Morgan were compelled to follow MG’s lead and restyle things
so the headlamps were faired in.
Concurrent with this, the Morgan factory took the opportunity to do one
of their rare styling changes, abandoning their long-establish upright radiator
grill for one mounted in a cowl that blended into the hood (bonnet). It wasn’t exactly the onset of modernity but
there presumably was some aerodynamic gain and just to assure buyers change wasn’t being made for the sake of change, disc
brakes would have to wait another few years.
The change to the grill was made in 1953 although, because of the way
Morgan operated, some of the older style cars were actually assembled later
than the new. The cars with the traditional
Morgan look which features the upright grill are known among aficionados as the
“flat radiator Morgans”. In a quirk of industry economics, when the 1961 Imperial range was released, Chrysler began manufacturing its own old-style “freestanding”
headlamp nacelles, four of which were mounted on short stalks within deeply scalloped front fenders, a motif recalling (vaguely) the 1930s which the designer dubbed “neo-classical” which may have been a bit of a leap from the term's origin in revivalist architecture. Imperial retained the look for three seasons although the tailfins were pruned for 1962 after in their final year setting the mark for verticality, peaking at their highest point just a fraction of an inch higher than the famous “twin bullet” installations on the 1959 Cadillac.

Impromptu
Flachkühler.
In October 2005, Lindsay Lohan went for a drive in her Mercedes-Benz SL 65 AMG roadster. It didn’t end well, a low-speed unpleasantness with a van resulting in her roadster suffering a Flachkühler. Based on the R230 (2001-2011) platform, the SL 65 AMG was produced between 2004-2012, all versions rated in excess of 600 horsepower, something perhaps not a wise choice for someone with no background handling such machinery though it could have been worse, the factory building 400 (175 for the US market, 225 for the RoW (rest of the world)) of the even more powerful SL 65 Black Series, the third occasion an SL was offered without a soft-top and the second time one had been configured with a permanent fixed-roof. A production number of 350 is sometimes quoted but those maintaining registers insist it was 400. Ms Lohan's SL 65 was later repaired and sold so all's well that ends well.
Rosemarie Nitribitt and Joe the poodle, with 190 SL, going to or coming from work.
The best-known owner of a Mercedes-Benz 190 SL (W121; 1955-1962) was Fraulein Rosemarie Nitribitt (1933-1957) who, by 1957, was Frankfurt’s most illustrious (and reputedly most expensive) prostitute, a profession to which she seems to have been drawn by necessity but at which she proved more than proficient and, as the reports of the time attest, there was nothing furtive in the way she plied her trade. Something of a celebrity in Frankfurt (the republic's financial centre), her black roadster became so associated with her business model that the 190 SL was by some referred to as the “Nitribitt-Mercedes” (and, less charitably, the Hurentaxi (whore's cab)), her car seen frequently, if briefly, parked in the forecourts of the city’s better hotels. The lives of prostitutes, even the more highly priced, can descend to their conclusion along a Hobbesian path and in 1957, aged 24, she was murdered in her smart apartment, strangled with a silk stocking, the body not found for several days. Given Fraulein Nitribitt operated at the upper end of the market, her clients tended variously to be rich, famous & powerful and that attracted the raft of inevitable conspiracy theories there had been a cover-up to protect their interests, a rather botched police investigation encouraging such rumors. The murder remains unsolved.
Frankfurt police officers examining Helga Matura's 220 SE cabriolet (Hōchkühler). Note the jackboots.
In a coincidence of circumstances and geography, a decade later, Fraulein Helga Sofie Matura (1933-1966) was another high-end prostitute murdered in Frankfurt, the weapon this time a stiletto (the stylish shoe rather than the slender blade). Never subject to the same rumors the Nitribtt case attracted, it too remains unsolved. In another coincidence, Fraulein Matura’s car was a convertible Mercedes, a white 220 SE Cabriolet (W111,
Hōchkühler). Despite the connection, the W111 never picked up any prurient nicknames and there was no reputational damage but claims Fraulein Nitribitt's murder contributed to 190 SL sales suffering appear over-stated. The W121's first year of full-production was 1956 with second-season drop-offs in sales not unknown and while at least in Germany, the association with the dead courtesan may have been off-putting for the bourgeoise, without qualitative data, one really can’t say. There was a precipitous decline in 190 SL sales in 1958 but that was the year of the worst US recession of the post-war years (1945-1973) and it was in the US most of the drop was booked; on both sides of the Atlantic, sales anyway quickly recovered.