Critical appraisal
British motoring journals viewed the 604 favorably upon its initial launch in the UK market,[31][17][73][74] though Motor dissented, viewing the car as generally being a "middle of the road" product.[75] Later commentary noted that its "excellence [was] widely acknowledged".[10] Throughout its career it was rated above all for its ride quality which Car magazine described as being superior to the 1980 Mercedes S-Class W-126 and the equal of Jaguar.[76] Motor magazine viewed the car's ride as being the equal of Jaguars and large Citroëns.[23] As a classic car, the 604 has acquired the lasting image of being "forgotten" and for being less successful than Peugeot hoped,[77] but it is also noted for its "outstanding" ride and accurate, communicative steering.[25]
In August 1975 Car magazine presented an initial review of the 604 and described it as "such a carefully conceived and thoroughly developed car that one can´t help be utterly impressed".[78] Criticisms concerned the weak airflow from certain vents, the slight lack of lumbar and lateral support from the front seats, brake fade, and the lack of central locking. Car praised the refinement of the suspension and the smoothness of the engine which was "an exceptionally flexible unit that has the ability to rev to dizzy heights without uttering the slightest complaint at either extremity".[78] The article concluded that "the Jaguar XJ6, the BMW 525/528, the Fiat 130, Mercedes 280E and Volvo 264 GL are going to have to close ranks against a formidable new intruder".[17]
In November 1975 Car magazine tested the 604 against the BMW 528 and Jaguar XJ 3.4. The test concluded the 604 was faster at cornering than the BMW 528 and was quieter and more comfortable.[79] Car viewed the 604's roadholding the equal of the Jaguar in the dry and superior in wet conditions and, as a limousine, was more successful than the Jaguar. Car concluded that "the Jaguar is still a brilliant car, but in some respects Peugeot have managed to better it. And that takes some doing".[80]
The UK's Motor weekly tested the 604 SL with four-speed manual transmission.[81] The article described the car's styling as both "subtle" and "discreet" with "superb ride, sumptuous and comfortable interior, vary spacious in the back" but the car was let down by its "lack of refinement".[75] The performance was called "lively" but "lacked power below 2,500 rpm", though from 2,500 it "pulled lustily and smoothly up to 6,000 rpm".[81] Detail criticism was focused on the ergonomics (awkward window switch placement, poor driver's seat adjustment, "fussy" speedometer markings), mediocre fuel consumption, and some minor assembly faults. The luggage capacity was described as average (12.6 cubic ft/357 litres). Comparatively, the more expensive Jaguar XJ6 3.4 was rated more highly for its ride and noise suppression while the BMW 520i was judged to be more sporting though overpriced. Motor described the Peugeot as being somewhere between the two.[82]
The Peugeot 604 went on sale in the US market in April, 1977.[83] The US magazine Motor Trend described the rack-and-pinion steering as being "of surpassing excellence and must be experienced to be appreciated" in a review of the 604 SL.[83] Turning to the suspension, Motor Trend wrote that "springing is soft with a great deal of wheel travel. Movement is damped in jounce and particularly rebound in the manner that only the French, and perhaps BMW, seem to be able to achieve".[83] Despite the comfortable ride, the handling remained secure. The car "leans a bit but clings like a limpet in both fast and slow curves".[84] Braking was described as "excellent", having a decelerating g-force of 0.875.[85] The only weak area was performance, the 604 "not coming up the standards of excellence set by ride, handling and stopping ability". The review added that "acceleration and speed are adequate to keep from being overrun by other traffic but by no means can performance be considered brilliant".[85] This was countered by the car's ability to maintain high average speeds on account of its capacity to cope with "twisting, poorly surfaced roads".
In November 1977 the UK's respected Car magazine ranked the 604 first in its Giant Test of the Peugeot, BMW 728 and Mercedes 280E.[86] Autocar's long-term test in 1977 of the 604 SL concluded it was very refined, let down mainly by the design of the front seats and minor mechanical defects.[87] In the following year, Car compared the fuel-injected 604 Ti with the Lancia Gamma and Rover 2600 and declared the Peugeot the best car out of the trio: "So strong is its appeal [...]that even the problems some of our team have with the driving position can´t turn us away from it, enhanced as it now is by the extra silkiness that the fuel injection brought, and the greater quietness when cruising that the five-speed transmission allows".[88]
In 1980, What Car? tested the 604 Ti against the newly introduced Vauxhall Royale, the Ford Granada 2.8 Ghia 'S', and Renault 30 TX. Whilst the Peugeot received commendation for its ride ("outstandingly good"[89]), "superb" headlamp performance, the comfort of the rear passenger compartment and the generously sized boot, it lost out to the Royale which was viewed as a more rounded overall design. The Peugeot's driving position, and in particular the design of the seat-runners and cushion, were singled out for particular criticism. Of the four cars, the Peugeot 604 Ti had the highest top speed (119 mph), best 0-60 performance (9.7 seconds) and best fuel consumption figures. It was also the lowest priced of the four cars (9,258 GBP versus the 10,018 GBP for the Ford, 9,771 GBP for the Vauxhall and 9,430 GBP for the Renault).[90] Autocar magazine carried out a long-term, 36,000-mile, test of the Peugeot 604D turbo.[91] The review concluded saying "This was one car we would dearly have loved to have kept in the family. It offers a rare combination of luxury, big car motoring at a very modest cost. And if this were not enough, the standards of ride and handling are difficult to match at any price".[92] The model was chosen by the magazine for testing because it "was the most advanced diesel engined car on the European market" when it was taken onto the magazine's fleet.[93]
In April 1983, Car magazine tested the 604 against the newly launched Volvo 760 and Ford Granada 2.8 Ghia X.[95] The reviewers rated the Peugeot's interior space, headlight effectiveness and ride quality as the best of the trio but the "dated and messy interior" counted against it.[96] Its performance and economy were also lagging behind the competitors. However, the authors still noted that, in their view, the 604 was "the best-riding car on sale today".[96]
Classic & Sportscar carried out a dual test of the Peugeot 604 SL four-speed manual with the Lancia Gamma Berlina (though did not rank them). The reviewer described the 604 as being "suave and smooth, always on its way to that ambassador's reception with a glovebox of Ferrero-Rocher." Criticism of the car focused on the "injection moulded dashboard [being] far from pretty" and the "slightly awkward 4-speed gearbox".[25] The tri-choke Solex carburettor arrangement also received a critical commentary, being responsible for leaving the driver "with an impression of a mid-range flat spot" though the car still "surges forward with brisk authority and a smooth lusty hum....".[25]