Q: What should be done if engine mounts are broken or deteriorated in 4.6L V8 engine on Cadillac DeVille?
A: Engine mounts seldom require attention, but broken or deteriorated mounts should be replaced immediately to prevent damage or wear on driveline components. The 4.6L VB engine features four main engine/transaxle mounts, along with a torque strut for 1999 models or a front and passenger side engine mount plus two transaxle/subframe mounts for 2000 and later models. To check the mounts, raise the engine slightly to relieve weight, then inspect for cracks, hardened rubber, or separation from metal plates, and check for movement between the mount plates and the engine or frame. If movement is noted, lower the engine and tighten the mount fasteners, and consider applying rubber preservative to slow deterioration. For replacement, disconnect the negative battery cable, raise the vehicle securely on jackstands, and remove the cooling fans and torque struts if equipped. Install an engine support fixture, detach the front mount from the subframe and engine, and remove the front brace bolts from the cylinder head before raising the engine to clear the motor mount stud(s) and removing the front engine mount. Installation follows the reverse procedure with threadlocking compound used on the threads. For the right side mount, repeat the process of removing torque struts, installing an engine support fixture, and detaching the mount from the engine and bracket. The subframe/transaxle mounts vary by year and model, with the left front mount attached to the transaxle near the frame and the rear mount positioned between the transaxle and subframe. After removing the necessary torque struts and using an engine support fixture, detach the mount from the transaxle and subframe/bracket, then raise the engine if needed to remove the front subframe/transaxle mount(s), ensuring secure installation with thread locking compound. The engine torque strut, mounted between the engine and upper radiator support, can be replaced without jacking up the engine by removing the through-bolts and bolts attaching the strut to the radiator support mounts, and may require a prybar for alignment during reinstallation. After installing the torque strut, ensure the engine/transaxle assembly is properly positioned without lifting devices before tightening the bolts securely with thread-locking compound.