I need a viscous coupling for a project that I'm working on. I've read that most cars have some inside, and I am thinking of going to the junkyard and scrapping one off a car. I am not by any means a car expert, so I have no idea where to look for the part. the wikipedia page has a section about their use in cars, but I still cant deduce where in a car they would be located. Can someone please tell me how I would go about removing one of these from a car in a scrapyard? Thanks.

  • What kind of size viscous coupling do you need, and what kind of application are you intending? It matters a lot. A fan viscous coupling may not meet your expectations in size and angular resistance, as it won't really engage at ambient temperatures. You may craft one yourself for it to suit your needs. I recently described [here]engineering.stackexchange.com/questions/18991/…) how to do that. – Bart Jan 22 '18 at 12:28

They are located on the radiator fans where the van is driven off the engine. So typically older vehicles or conventional transaxle RWD cars and trucks.

Typical vehicles which have a viscous coupling fan would be: Landrovers pre 2005 Heavy duty trucks such as Scania, Daf, Volvo etc RWD Ford transits and a lot of conventional 4x4s or large engined RWD vehicles

Another type of viscous coupling would be a torque convertor located between the engine and a automatic gearbox. This is used instead of a clutch in a manual gearbox. These can still be found in modern automatics but a lot now have conventional clutches which are computer controlled.

Vehicles which I know have a torque converter are: Landrover automatics pre 2005 BMW automatics pre 2012 (post 12 may do but I'm not sure) and most automatics pre 2000 will be very likely to have a torque convertor

  • Volvo 4wd had viscous couplings to drive rear axle - common point of failure if people did not keep all 4 tyres the same... – Solar Mike Jan 21 '18 at 19:52
  • A torque converter is filled with transmission fluid that is tied into the rest of the transmission. It is far to complex to keep it fed with oil and keep it from leaking. A fan clutch is the best bet. – vini_i Jan 22 '18 at 9:07

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