I have a '96 Disco (4.0 V8) w/ ~100k miles. At ~78k miles, I began noticing a brief squealing noise on startup (lasts ~30 seconds). The noise only occurs on the 1st startup of the day. The dealer's service center thought it was the drive belt & tensioner pulley and replaced both components @ 82k miles. The noise "reappeared" shortly thereafter and hasn't gotten worse (or better). I read about how the viscous drive unit for the engine cooling fan works in the Land Rover Discovery Work Shop Manual. Could this be the source of the noise? If so, is it just noise or an indication of a future component failure? Engine temperature has remained normal under all driving conditions.