Ask if the manifold gasket has been changed recently. IF it has, you would be good to go. If not, negotiate the cost of possible repair out of the price. If it works out and you buy the car, have the manifold gasket changed right away. My sister has a 1995 hardtop with the 3.4 with 84K on it and no leak yet. Not to say it won't leak eventually.....
And what belt are you referring to? I have not heard of that issue
John