Tensioner Installation I Tensioner Adjustment
Cambelt Tensioners
TENSIONERS Since 1993, in the North American market, this tensioner has been standard equipment on Alfa Romeo 164 V6, and has been retro-fitted to many earlier 164's and other models with V6. It fits 12-valve 3.0L and 2.5L V6's. The "old-style" tensioners are permanently fed with engine oil and are renowned for worsening oil leaks after relatively little engine use. Alfa North America changed to a "new-style" tensioner which is not dependant on an oil supply for its function: it is "thermo-mechanical" rather than "hydraulic" in function. It maintains correct tension on the cambelt by means of a temperature-sensitive spring-loaded bearing. When fitting the mechanical tensioner the oil supply is sealed off and there are no oil seals to leak. No servicing is required. Replace the mechanical tensioner with a new unit after 30,000 - 35,000 mi (50,000 - 55,000 kms). ALFA ROMEO (ARDONA) PARTS: AVAILABLE FROM: TOOLS/SUPPLIES YOU REQUIRE: CAUTIONS!: Also, the engine must not rotate in reverse at any time with this tensioner installed. With an automatic transmission such as in the 164 this is not a problem but the engine can rotate in reverse in a manual transmission vehicle (for example) if it rolls backwards on a hill. Extreme care should be taken when driving not to allow any reverse motion of a manual gearbox vehicle while in a forward gear. WE DO NOT RECOMMEND RETRO-FITTING THIS UNIT TO A MECHANICAL TRANSMISSION CAR, ONLY TO AUTOMATICS. 
INFORMATION
Heat sensitive 'mechanical' cambelt de-tensioner with integrated bearing (part number 60588421). Plug 8mm (part number 60897507). Adaptor stud 10mm/8mm (part number 60897506).
International Auto Parts
Centerline Alfa
Alfa Parts
A high quality oil-sealing threadlocker (Alfa recommends Würth 'blue', part number 8932423 but we use other reputable brands), 8X1.25mm (metric) thread tap, metric hex drivers or Allen keys, 1/4" & 17/64" drills, 3/8 square socket driver.
The thermo-mechanical tensioner requires very careful installation and adjustment. This and any work involving engine timing has to be carried out meticulously. If you are not confident of your abilities, seek professional assistance. Never over-torque the unit during adjustment but do not install it under the recommended pressure on the cambelt. Loss of cambelt tension appears to be a danger to the tensioner's fragile external control spring and if it fails you may do considerable damage to your engine.