Engine rolling front/back, which motor mount is the culprit?

[nardvark]

I had my wife give the car some gas in Drive (or reverse, for that matter) with her left foot on the brake, and the engine has a good 2 inches of movement, front to back.

My suspicion is that the dogbone mount has gone bad. I can see the dogbone flexing as the engine rotates up away from it, but I can also see the engine connection to the passenger side mount moving significantly. There, it's moving pretty much straight horizontal, while I think the passenger mount is designed mostly to constrain the vertical motion...is that correct?

It could be that both are shot, since one dying is probably putting more stress on the other. I can't see the third mount well enough to tell what's going on there.

Anyone have a good test to isolate which mount has gone bad?

 

[USAFVMI08]

It could be that both are shot, since one dying is probably putting more stress on the other.

This. When I replaced my rear motor mount with an upgraded one, my passenger mount gave out a little less than a year later.

 

[nardvark]

Well, that's a little different. If you put in a stiffer mount at one location, it puts extra stress on the others.

 

[USAFVMI08]

Not exactly. If you have a mount going bad...that one good mount is going to put more stress on the bad mount.

 

[nardvark]

Ah, gotcha, makes sense.