Whine from Mondial t motor

Strange occurrance... in an '89n Mondial t - I have a strange whine sound (almost as a quiet version of an alternator belt slipping when wet squeal) from the engine. It only happens when the motor is at good running temperature, and I have given it some stick. Eg. if I'm on a clear road, going pedal to the metal up to 100 mph, then stopping at the next traffic light, then when it goes down to idle it starts with the whine... Not metallic or anything to suggest anythign scary. To add to the strangeness, if I switch the engine off, then immediately restart it, the whine goes away. If I drive along normally, it does not come back, but if I rip it on then it does come back. Everytime thoug, switching the engine off and back on seems to be the "reset"...

I did take the cam-belt covers off, and the belt looks OK - no balt patrches, all looking normal. The belt service was done in Sept '06, and the car has driven 14K mi since (though 3K miles I did in 72 hours driving to Denmark, Paris and Milan all in one trip in a pan-European race with 2 Porsches and an Aston Martin - all youger than 4 years - and I won by being more disciplined, resting less and driving faster when the other's didn't dare - at night)

It really has me stumped. None of the accessory belts are slipping to my knowledge - alternator works tip-top (voltage & amp measurement), AC works fine, PAS works fine and exactly the same weather or not there is any whine.

Marco

 

Can't help myself to want to respect what the intention was in building these cars - to be used. If they were meant to be kept indoors they'd be sculptures and be of stone. My life is richer for every mile I do in it!