RepairPal Certified shops can diagnose and repair your 1998 Cadillac Catera. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
The engine oil cooler in under the intake manifold on your Catera engine. Autozone has online repair manuals available at the following link: athttp://bit.ly/online_repair_manuals
Good luck!