On 27 Feb 2020 14:51:23 GMT, Tim+ wrote:

snip

The last car that I had that definitely had a viscous coupled fan was a
Volvo 240 which always gave a distinctive “roar” on start up from cold
until the coupling started slipping.

Whilst that makes sense on a PC fan to blow the dust out g, I don't
remember it happening on the viscous coupled fan on my 2L Sierra
Estate?

On cold start it may have idled round from the drag in the system but
you could very easily hold it when starting and you could only just
feel it trying to turn?

Once the heat starts blowing though from the rad however, it really
firms up and does it thing.

It sounds like the Volvo one worked differently?

Cheers, T i m