After six month of testing I measured the VC once again on the test rig and got the following result.<\/p>\n You can clearly see the increase in viscosity and hump-temperature. Therefore I recommend a lower hump-temperature \u2013 because it\u2019s steadly increasing. The process decelerates over time, but after 100 to 150.000km the VC will look like that:<\/p>\n The viscosity of that aged silicon oil in the VC would be like 60.000AK. Such a VC wouldn\u2019t damage the transmission, but parking without power-steering can be quite hard.<\/p>\n WHAT CAN BE DONE?<\/strong><\/p>\n The process of oxidation can be avoided by replacing the oxgen from the air with Co2. W.Peschke researched this phenomena in his dissertation and provides some evidence about that:<\/p>\n And also the german silicon-oil manufacturer \u201cWacker\u201d writes about a higher temperature-resistance of the silicone-oil in a Co2-atmosphere.<\/p>\n With the help of a vaccum pump I was able to degas the silicon oil and replace the oxgen with Co2. Also interesting is the amout of dissolved air in the silicon-oil. Here<\/a> you can see a short clip of degassing silicon oil.<\/p>\n The degassing takes quite a long time (48h) \u2013 unfortunately otherwise gas-bubbles will make problems with the filling.<\/p>\n Continous test runs have already shown the non-existing aging of the Co2 Viscous-couplings. But in addition I also made an on- and off-road test over 10.000km.<\/p>\n And here you can see the before and after diagram:<\/p>\n As you can see, there\u2019s practically no aging of the silicon oil. Although unequal worn tires were used for the test-setup. In the future I will \u00a0sell the improved Co2- Viscous Couplings only.<\/p>\n UPDATE 2020:<\/strong><\/p>\n A Syncro driver from mountainous Vorarlberg (Austria) subjected our Co2-Visco to a long-term test from 2016 to 2020. Back in summer of 2016 we were contacted after the Syncro driver had to complain about a defective VC (from a competitor) after only 10tkm.<\/p>\n With the intention only to take the role of an appraiser, the Syncro driver had lost faith in the principle of the viscous coupling and was thinking of converting the Syncro with a decoupler. We were able to convince him to try it once again with our improved Co2-VC.<\/p>\n![\"Aging](\"https:\/\/vw-kern.at\/blog\/wp-content\/uploads\/2016\/06\/BILD1.jpg\")
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