Q: What are the steps involved in checking and replacing powertrain mounts on Nissan Maxima with DOHC engine?
A: There are four engine mounts,front and rear mounts at the center of the vehicle connected to the engine block and lower crossmember, a right side mount attached to the front of the timing cover and frame, and a left side mount connected to the transaxle and frame. To check the mounts, the engine must be raised slightly to relieve weight from them. The vehicle should be raised and securely supported on jackstands, with the engine/transaxle supported from above using a hoist or engine support fixture. The mounts should be inspected for movement; if any is detected, the engine should be lowered and the mount fasteners tightened. Additionally, rubber preservative should be applied to the mounts to slow deterioration. For replacement, disconnect the cable from the negative battery terminal, set the parking brake, block the rear wheels, raise the front of the vehicle, and support it securely on jackstands. Remove the splash shields and, if applicable, disconnect the wiring harness for the electronically controlled engine mount. Position a floor jack under the transaxle case with a wood block in between, then remove the through-bolts from the front and rear mounts, detach the crossmember from the vehicle, and remove the mount-to-engine bracket through-bolts. Installation follows the reverse order, ensuring bolts are tightened to specifications only after the engine weight is back on the mounts. For the right side engine mount, support the engine from above, remove the upper engine mount bracket and through-bolt, raise the engine slightly, and remove the mount. The left side transaxle mount requires positioning a floor jack under the transaxle housing, removing the air cleaner housing and intake duct, and then removing the transaxle-to-mount bolts. Final tightening should be done with the vehicle level and the engine weight on the mounts, using thread-locking compound on the nuts/bolts, ensuring bushings are not twisted or offset. If more than one mount has been replaced, the tightening order should be crossmember bolts, rear engine mount, front engine mount, left-side transaxle mount, and right side engine mount. If the vehicle has an electronic engine mount, the wiring harness should be reconnected, ensuring the distance between the two harness retainers on the mount is 6.69 inches (170 mm) for 2003 and earlier models.