Broken motor mount?
Thread Starter
Instructor
Joined: May 2005
Posts: 184
Likes: 13
Broken motor mount?
My car is a 74 with a 396 big block. When at normal idle the motor seems to be rocking back and forth (left to right) quite a bit more than I've noticed before. The car seems to be running fine on the road. I installed heavy duty motor mounts when the car was built and it only has been driven about 2,000 easy miles since then. I find it hard to believe one has broken, but you never know.
Earlier this week I did find that the number 4 spark plug was defective and I thought that was causing the problem, but I replaced all the plugs so I must have something else going on here. I also ordered new plug wires just in case and I'm waiting for them to arrive.
So my question is, how do I check for a broken motor mount? Any suggestions on what would indicate a broken mount? Any suggestions would be appreciated.
Earlier this week I did find that the number 4 spark plug was defective and I thought that was causing the problem, but I replaced all the plugs so I must have something else going on here. I also ordered new plug wires just in case and I'm waiting for them to arrive.
So my question is, how do I check for a broken motor mount? Any suggestions on what would indicate a broken mount? Any suggestions would be appreciated.
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 787
From: Lebanon Township New Jersey
Only the drivers side mount ever normally breaks. If you have an automatic trans, start the engine, step on the brakes, put trans in D, step on the gas a little and see if the engine lifts up on the drivers side. With a manual you need 3 feet or a helper to work the throttle, unless your ebrake is real good.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
Careful. A broken LH motor mount can possibly allow the engine to move far enough to send the fan into the radiator shroud and pull the inlet tube off the radiator.
Don't ask me how I know, I don't want to talk about it.
The motor mounts that interlock are the safest kind. When the rubber breaks, the engine can only move a little bit.
Don't ask me how I know, I don't want to talk about it.
The motor mounts that interlock are the safest kind. When the rubber breaks, the engine can only move a little bit.
