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http://en.wikipedia.org/wiki/List_of_GM_engines#DieselThe history of Diesel engines at General Motors has not been positive. In the face of the 1970s 'gas crisis', GM turned to Diesel power for economic benefit, directing the Oldsmobile division to develop a V6 and two V8 engines, to be shared with all divisions.
These Diesel engines were designed to fit into the engine bays of gasoline powered automobiles, but despite popular belief, they were not "converted" gasoline engines. Oldsmobile's diesel engines, the 5.7 L LF9 and 4.3 L LF7 V8s and 4.3 L LT6/LT7/LS2 V6, were notoriously unreliable, particularly in the earliest versions, though reliability had improved by the early 1980s with the advent of the DX block, along with better fuel filtering and water separators. Many of the reliability issues these engines developed were a combination of faults not just related to design. Many of these engines suffered major malfunctions from poor quality fuel, mechanics not properly trained in diesel repair, and even improper owner service and maintenance. Although over one million were sold between 1978 and 1985, the failure rate of GM's engines ruined the reputation of Diesel engines not just built by GM, but overall in the United States market. Eventually, a class action lawsuit resulted in an arbitration system under the supervision of the Federal Trade Commission where consumers could claim 80% of the original cost of the engine in the event of a failure.
The Oldsmobile 5.7 liter engines experienced a wide gamut of malfunctions. One of the common failures was with crankshaft bearings. This was frequently attributed to owners and maintainers running the engines on SG rated oil (intended for gasoline engines), versus CD oil (intended for Diesel engines). This prompted GM to introduce the DX block, which had larger oil passages and a higher volume oil pump, so that the engines could tolerate low-grade oils. These engines also suffered from blown head gaskets, warped heads, bad injector pumps, and bad injectors. The beginnings of these problems can be attributed to poor quality diesel fuel that may have contained water or other contaminants. These materials would damage the inside of the injector pump, and then eventually clog injectors. If water was injected into the engine, it could cause a "hydrolock" which would blow head gaskets and bend valves because water cannot be compressed. This was the reason GM equipped later cars with water detectors and double filtration systems on their vehicles.
When a hapless owner took the vehicle in for repair, the mechanic would resurface the head, making it thinner, install a new head gasket, and then reuse the old, stretched-out fasteners. It would not be but a few thousand miles, and the vehicle was in the shop again for head gasket failure or a warped head. The frustrated owner would frequently just get the shop to convert the engine to gasoline after a few repeated failures like this. As a side note, these diesel engine blocks were frequently sought by hot-rodders to build high-performance gasoline engines because of their extra heavy duty components which would withstand extreme horsepower.
In the 1980s and 1990s GM produced the 6.2 L and 6.5 liter V8 Diesels for use in light trucks and in the HMMWV.
Today, GM uses Diesel engines from Isuzu Duramax (for trucks) but offers no domestic Diesel passenger cars. General Motors' Opel division is one of the leading proponents of Diesel cars in Europe, however. In the 1970s, Opel developed the first Opel Diesel engine ever. This 2.1-litre engine made some records in a car specially built for this purpose, the Opel Rekord D (2100 ccm, 60 hp). Later versions were used in the Rekord E and the Ascona B. Vehicles using these engines could be identified by a little "hill" in their hoods. Without this "hill" in the hood, the space for the engine would have been too small. Kadett D, E and Ascona B and C models also used an Opel engine (1600 ccm, 54 hp). Later Isuzu engines were installed, namely for the Corsa A (1500 ccm, 50 hp and 1500, turbo, 67 hp) as well as for the Kadett E and Vectra A (Vectra A TD: 82 hp).
Opel today uses common rail direct injection engines designed and produced by Fiat S.p.A and Isuzu. Ownership of both designs was acquired by GM in 2005, and a new GM Powertrain division in Turin, Italy (home of Fiat) was founded to manage these assets. The Fiat Diesel engine has 1900 ccm, but before this cooperation, Opel had already developed two own engines, namely 2-litre Diesels with 82 and 100 hp; which were installed mostly in the Vectra B. GM Daewoo recently licensed two common rail designs from VM Motori.
Many of the failures and complaints GM endured have shaped the design of Diesel engines today to be quite reliable and good performing engines. Today's Diesels have excellent fuel filtration systems to minimize failures of injection systems. Many manufacturers require owners to use specific types of oils in their diesel engines, and the use of these oils must be proven for warranty claims (Volkswagen TDI). Drivers also complained of the lack of power, unpleasant noise, and the dirty, smelly exhaust from early GM diesels. Today's diesels with common-rail injection tackle all these shortcomings. They are extremely efficient, yet provide significantly more power than older diesels, and they do so with significantly less pollution and noise. Today's dealer mechanics have also undergone the proper training to service the engines properly.
