And aftermarket viscous fan clutches are notoriously poor quality and rarely in spec. I had some success in refilling them, which is pretty simple to do. Over time the oil leaks out and they start acting up.
-D > On Mar 14, 2020, at 10:02 AM, Peter Frederick via Mercedes > <mercedes@okiebenz.com> wrote: > > The fan clutch kicks in around 80C and should keep you at normal operating > temp unless you have the AC on, in which case as long as there is high > temperature on the high pressure side of the compressor the fans will run at > low speed. > > They should NOT be on in normal driving. > > You have a bad fan clutch -- easy to test. With the engine warm enough for > the clutch to be engaged you should hear it roaring and when the engine is > shut of it should stop within a second or two. On startup cold you should > hear it run for a few seconds as the clutch fluid spins out of the plates. > > If it's not pushing quite a bit of air with a warm engine, it's dead and > needs to be replaced. > > Been there a number of times, probably 90% of your trouble is a dead visco > clutch. > > The rest of it is either a bad ground or a bad electric fan motor or two. > Since they both run it's not the last issue, something stuck in them to > prevent rotation. > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
