The thermostat is usually 87C, they'll normally run right around 80C on the gauge, maybe a little higher. Haven't had big thermostat probs on 104 engines like yours. Possibly there is a build up of leaves and other "krahp" between the A/C condensor and the radiator. Also I believe on this particular model, there are 2 fans in front of the radiator, the one on the drivers side has the motor, and the one on the passenger side is driven off of the drivers side via a thin rubber belt. We've had some problems with the belt coming off. Just raise the hood with the engine off, spin the hub on the drivers side fan, and the passengers side should rotate also. If the passengers side does not rotate, this may be part of the problem.