DO NOT TAKE TO DEALER unless you have money to burn.
I have 98 catera with everyone of the bs problems associated. I can help. the leak is probably due to heater control valve breaking off the bracket mount its connected too....the heater control valve has three stems that branch off and off this is a tee connector hose piece. the tee connector has curely-q like bend to it that if not positioned high enough, will rest of the coolant inlet pipe and might even rest up on the manifold heat sheilds.. either case both of these get hotter that hell, hot enough to melt rubber hoses...............you can get access to the back of the engine where the heater valve and hoses-here's how.
1)take off the cowl and the air grille(where the cabin air fillter goes)
2)remove the windshield wiper motors, control bars, and wipers
3)remove the air resenator, intake plenum, intake manifold, throttle body.
on the throttle body removal, if you simply disconnect the two silve fuel lines feed from the bracket, and throttle body coolant lines, one right side pointing forwards, one left side pointing port side, you'll keep the throttle body connected to the intake manifold and is much easier to put back later.
4) it is easier to go ahead and take the fuel rail/injector tree out, toremove the inj tree-don't be afraid to put some umpffff behind it-cause those guys are inthere tight. plus you can go ahead and get some carb cleaner and cleaner the gunk on the injectors themselves.
5) make sure you mask off the openings exposed, its just safer
6)remove the coolant inlet pipe just to make sure the oring isn't trashed
These are the basis, if you have any questions, the damn service manuals are not very helpful, the same bullshit is on alldata for 25.00 don't waste the money. Ihave manuals for 98 if you need diagrams or get stuck, I'll help get ya out.
the repairs are not rocket science, but more time consuming and lack of information from Cadillac only pisses off the problem. Oh yeah by the way if you have bad valve covers, my mistake cylinder head covers, don't bother getting the damn things from dealer at 58.00 per side and 1.75 per oring(16 total) get the gasket maker from autozone, OEM gasket maker about 15.00$ per can, get 2 cans-orings take a bit to make.........same shit gm uses on the transmission casing and the oil pan-upper.