XUD engine | |
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Overview | |
Manufacturer | PSA |
Production | 1982–2001 |
Combustion chamber | |
Configuration | inline-four |
The PSA XUD is a Diesel engine designed and built by PSA - Peugeot and Citroën. It is an Indirect Injection (IDI) engine, that uses a version of the Ricardo Consulting Engineers Ricardo Comet V prechamber cylinder head design. The engine comes in 1,769 cc 1.8 N/A, 1.8 Turbo, 1,905 cc 1.9 N/A, 1.9 Turbo, 2.1 12 valve N/A and Turbo and was the predecessor to the HDI range of engines. Early HDi Engines were a PSA design, later 16 valve engines were jointly developed with Ford.
The XUD was available with either SOHC 8-valve or 12-valve heads. It was mainly applied transversally in front wheel drive vehicles, tilted by 30°. However, some applications in non-PSA vehicles had the engine installed longitudinally, with rear-wheel drive. The XUD is built in Citroën's plant in Trémery, near Metz.
Displacement ranges between 1,769 and 2,138 cc, and all XU diesel engines have a stroke of either 88 mm (3.5 in) or 92 mm (3.6 in). The former was shared with the XU9. Bore sizes range from 80 mm (3.1 in) to 86 mm (3.4 in), some of which are shared with other XU engines.
Upon its release the engine was noted as one of the best diesel engines (for cars and light vans) in the world with its high power output and refinement it made all other diesel engines seem agricultural. It was also particularly light, with a ready-to-run XUD9 weighing 157 kg (346 lb), 15% less than a comparable diesel of the previous generation. However, if the cooling system is neglected or improperly bled after filling - needing a raised filling level because the expansion tank is not the highest point in the system - the engine has a tendency to blow its head gasket. A simple solution is to use a plastic soft drink bottle with the bottom removed, fitted with a rubber O ring seal on the flange at the cap end for filling. Because radiators (typical life 100,000 miles), generally have only just sufficient cooling capacity when new, in order to help get the engine to operating temperature quickly, silting causes significant problems. Coolant changes to maintain corrosion inhibitors (and stop silting) are critical on this engine. Nonetheless due to the high volume of cars manufactured with this engine spare parts are plentiful and well priced.