95 Riviera motor vibration

[Franshean]

Hey guys hope you can help me. I just installed another motor in my 1995 Riviera. The motor has a vibration. There is no knocking of any sort just a vibration. Just wondering what it can be. Can it be a manifold leak what do you guys think.

[maxwedge]

From here a vibration is tough to advise on, bad balancer on the crank, motor mounts and on it goes, see if it changes torquing in reverse or dr. check the exhaust for grounding.

[edwinn]

Originally Posted by Franshean

Hey guys hope you can help me. I just installed another motor in my 1995 Riviera. The motor has a vibration. There is no knocking of any sort just a vibration. Just wondering what it can be. Can it be a manifold leak what do you guys think.

I've owned a 1997 Riviera since Feb 1998 and the motor was vibrating badly from the git-go. The dealer installed a new right rear (underneath power steering pump) motor mount and the vibration went way down. There has always been 'some' vibration in cold weather, yet very smooth in hot weather. A year or two ago I broke the same right rear motor mount and the bad roughness came back. My mechanic diagnosed it by applying brake, putting in reverse gear, stepping on accelerator and then cutting throttle. If mount is broken, the motor will rise-up in back, then drop down with a thud when the gas is cut. Have someone do this while you observe under hood. My mechanic guy then replaced the right rear mount aGaiN with a revised GM mount. They are rather expensive so be sure that's the problem. It still vibrates a little in temps below 60°F. Another former Riv owner in this forum also had same vibration in cold weather.

-edwinn